Major contributors (alphabetic order):
Mailing list for comments: info-gnuplot@dartmouth.edu
Mailing list for bug reports: bug-gnuplot@dartmouth.edu
GNUPLOT is a command-driven interactive function plotting program.
For help on any topic, type help followed by the name of the topic.
The new GNUPLOT user should begin by reading the introduction topic (type help introduction) and about the plot command (type help plot). Additional help can be obtained from the USENET newsgroup comp.graphics.gnuplot.
copyright
introduction
cd
clear
command line-editing
comment
environment
exit
expressions
fit
help
if
load
call
pause
plot
print
pwd
quit
replot
reread
reset
save
set-show
shell
splot
start-up
substitution
update
user-defined
bugs
list of demos
Copyright (C) 1986 - 1993 Thomas Williams, Colin Kelley
Permission to use, copy, and distribute this software and its documentation for any purpose with or without fee is hereby granted, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation.
Permission to modify the software is granted, but not the right to distribute the modified code. Modifications are to be distributed as patches to released version.
This software is provided "as is" without express or implied warranty.
AUTHORS
Original Software:
Thomas Williams, Colin Kelley.
Gnuplot 2.0 additions:
Russell Lang, Dave Kotz, John Campbell.
Gnuplot 3.0 additions:
Gershon Elber and many others.
There is a mailing list for gnuplot users. Note, however, that the
newsgroup
comp.graphics.gnuplot
is identical to the mailing list (they
both carry the same set of messages). We prefer that you read the
messages through that newsgroup, to subscribing to the mailing list.
(If you can read that newsgroup, and are already on the mailing list,
please send a message info-gnuplot-request@dartmouth.edu, asking to be
removed from the mailing list.)
The address for mailing to list members is
info-gnuplot@dartmouth.edu
and for mailing administrative requests is
info-gnuplot-request@dartmouth.edu
The mailing list for bug reports is
bug-gnuplot@dartmouth.edu
The list of those interested in beta-test versions is
info-gnuplot-beta@dartmouth.edu
GNUPLOT is a command-driven interactive function plotting program. It is case sensitive (commands and function names written in lowercase are not the same as those written in CAPS). All command names may be abbreviated, as long as the abbreviation is not ambiguous. Any number of commands may appear on a line, separated by semicolons (;). Strings are indicated with quotes. They may be either single or double quotation marks, e.g.,
load "filename"
cd 'dir'
Any command-line arguments are assumed to be names of files containing GNUPLOT commands, with the exception of standard X11 arguments, which are processed first. Each file is loaded with the load command, in the order specified. GNUPLOT exits after the last file is processed. When no load files are named, gnuplot enters into an interactive mode.
Commands may extend over several input lines, by ending each line but the last with a backslash (\). The backslash must be the LAST character on each line. The effect is as if the backslash and newline were not there. That is, no white space is implied, nor is a comment terminated. Therefore, commenting out a continued line comments out the entire command (see comment).
In this documentation, curly braces ({}) denote optional arguments to many commands, and a vertical bar (|) separates mutually exclusive choices. GNUPLOT keywords or help topics are indicated by backquotes or boldface (where available). Angle brackets (<>) are used to mark replaceable tokens.
For help on any topic, type help followed by the name of the topic.
The new GNUPLOT user should begin by reading about the plot command (type help plot). Simple Plots Demo
The cd command changes the working directory.
Syntax:
cd "<directory-name>"
The directory name must be enclosed in quotes.
Examples:
cd 'subdir'
cd ".."
The clear command erases the current screen or output device as specified by set output. This usually generates a formfeed on hardcopy devices. Use set terminal to set the device type.
The Unix, Atari, VMS, MS-DOS and OS/2 versions of GNUPLOT support command line-editing. Also, a history mechanism allows previous commands to be edited, and re-executed. After the command line has been edited, a newline or carriage return will enter the entire line regardless of where the cursor is positioned.
The editing commands are as follows:
Line-editing:
^B moves back a single character. ^F moves forward a single character. ^A moves to the beginning of the line. ^E moves to the end of the line. ^H and DEL delete the previous character. ^D deletes the current character. ^K deletes from current position to the end of line. ^L,^R redraws line in case it gets trashed. ^U deletes the entire line. ^W deletes the last word.
History:
^P moves back through history. ^N moves forward through history.
On the IBM PC the use of a TSR program such as DOSEDIT or CED may be desired for line editing. For such a case GNUPLOT may be compiled with no line editing capability (default makefile setup). Set READLINE in the makefile and add readline.obj to the link file if GNUPLOT line editing is to be used for the IBM PC. The following arrow keys may be used on the IBM PC and Atari versions if readline is used:
Left Arrow - same as ^B. Right Arrow - same as ^F. Ctl Left Arrow - same as ^A. Ctl Right Arrow - same as ^E. Up Arrow - same as ^P. Down Arrow - same as ^N.
The Atari version of readline defines some additional key aliases:
Undo - same as ^L. Home - same as ^A. Ctrl Home - same as ^E. ESC - same as ^U. Help - help' plus return. Ctrl Help - help '.
(The readline function in gnuplot is not the same as the readline used in GNU BASH and GNU EMACS. It is somewhat compatible however.)
Comments are supported as follows: a # may appear in most places in a line and GNUPLOT will ignore the rest of the line. It will not have this effect inside quotes, inside numbers (including complex numbers), inside command substitutions, etc. In short, it works anywhere it makes sense to work.
A number of shell environment variables are understood by GNUPLOT. None of these are required, but may be useful.
If GNUTERM is defined, it is used as the name of the terminal type to be used. This overrides any terminal type sensed by GNUPLOT on start up, but is itself overridden by the .gnuplot (or equivalent) start-up file (see start-up), and of course by later explicit changes.
On Unix, AmigaDOS, AtariTOS, MS-DOS and OS/2, GNUHELP may be defined to be the pathname of the HELP file (gnuplot.gih).
On VMS, the symbol GNUPLOT$HELP should be defined as the name of the help library for GNUPLOT.
On Unix, HOME is used as the name of a directory to search for a .gnuplot file if none is found in the current directory. On AmigaDOS, AtariTOS, MS-DOS and OS/2, GNUPLOT is used. On VMS, SYS$LOGIN: is used. See help start-up.
On Unix, PAGER is used as an output filter for help messages.
On Unix, AtariTOS and AmigaDOS, SHELL is used for the shell command. On MS-DOS and OS/2, COMSPEC is used for the shell command.
On AmigaDOS, GNUFONT is used for the screen font. For example: "setenv GNUFONT sapphire/14".
On MS-DOS, if the BGI interface is used, the variable BGI is used to point to the full path of the BGI drivers directory. Furthermore SVGA is used to name the Super VGA BGI driver in 800x600 res., and its mode of operation as 'Name.Mode'. E.g., if the Super VGA driver is C:\TC\BGI\SVGADRV.BGI and mode 3 is used for 800x600 res., then: 'set BGI=C:\TC\BGI' and 'set SVGA=SVGADRV.3'.
The commands exit and quit and the END-OF-FILE character will exit GNUPLOT. All these commands will clear the output device (as the clear command does) before exiting.
In general, any mathematical expression accepted by C, FORTRAN, Pascal, or BASIC is valid. The precedence of these operators is determined by the specifications of the C programming language. White space (spaces and tabs) is ignored inside expressions.
Complex constants may be expressed as the {<real>,<imag>}, where <real> and <imag> must be numerical constants. For example, {3,2} represents 3 + 2i; {0,1} represents i itself. The curly braces are explicitly required here.
The functions in GNUPLOT are the same as the corresponding functions in the Unix math library, except that all functions accept integer, real, and complex arguments, unless otherwise noted. The sgn function is also supported, as in BASIC.
abs
acos
arg
asin
atan
besj0
besj1
besy0
besy1
ceil
cos
cosh
erf
erfc
exp
floor
gamma
ibeta
inverf
igamma
imag
invnorm
int
lgamma
log
log10
norm
rand
real
sgn
sin
sinh
sqrt
tan
tanh
The abs function returns the absolute value of its argument. The returned value is of the same type as the argument.
For complex arguments, abs(x) is defined as the length of x in the complex plane [i.e., sqrt(real(x)**2 + imag(x)**2) ].
The acos function returns the arc cosine (inverse cosine) of its argument. acos returns its argument in radians.
The arg function returns the phase of a complex number, in radians.
The asin function returns the arc sin (inverse sin) of its argument. asin returns its argument in radians.
The atan function returns the arc tangent (inverse tangent) of its argument. atan returns its argument in radians.
The besj0 function returns the j0th Bessel function of its argument. besj0 expects its argument to be in radians.
The besj1 function returns the j1st Bessel function of its argument. besj1 expects its argument to be in radians.
The besy0 function returns the y0th Bessel function of its argument. besy0 expects its argument to be in radians.
The besy1 function returns the y1st Bessel function of its argument. besy1 expects its argument to be in radians.
The ceil function returns the smallest integer that is not less than its argument. For complex numbers, ceil returns the smallest integer not less than the real part of its argument.
The cos function returns the cosine of its argument. cos expects its argument to be in radians.
The cosh function returns the hyperbolic cosine of its argument. cosh expects its argument to be in radians.
The erf function returns the error function of the real part of its argument. If the argument is a complex value, the imaginary component is ignored.
The erfc function returns 1.0 - the error function of the real part of its argument. If the argument is a complex value, the imaginary component is ignored.
The exp function returns the exponential function of its argument (e raised to the power of its argument).
The floor function returns the largest integer not greater than its argument. For complex numbers, floor returns the largest integer not greater than the real part of its argument.
The gamma function returns the gamma function of the real part of its argument. For integer n, gamma(n+1) = n! . If the argument is a complex value, the imaginary component is ignored.
The ibeta function returns the incomplete beta function of the real parts of its arguments. p, q > 0 and x in [0:1] If the arguments are complex, the imaginary components are ignored.
The inverf function returns the inverse error function of the real part of its argument.
The igamma function returns the incomplete gamma function of the real parts of its arguments. a > 0 and x >= 0 If the arguments are complex, the imaginary components are ignored.
The imag function returns the imaginary part of its argument as a real number.
The invnorm function returns the inverse normal distribution function of the real part of its argument.
The int function returns the integer part of its argument, truncated toward zero.
The lgamma function returns the natural logarithm of the gamma function of the real part of its argument. If the argument is a complex value, the imaginary component is ignored.
The log function returns the natural logarithm (base e) of its argument.
The log10 function returns the logarithm (base 10) of its argument.
The norm function returns the normal distribution function (or Gaussian) of the real part of its argument.
The rand function returns a pseudo random number in the interval [0:1] using the real part of its argument as a seed. If seed < 0 the sequence is (re)initialized. If the argument is a complex value, the imaginary component is ignored.
The real function returns the real part of its argument.
The sgn function returns 1 if its argument is positive, -1 if its argument is negative, and 0 if its argument is 0. If the argument is a complex value, the imaginary component is ignored.
The sin function returns the sine of its argument. sin expects its argument to be in radians.
The sinh function returns the hyperbolic sine of its argument. sinh expects its argument to be in radians.
The sqrt function returns the square root of its argument.
The tan function returns the tangent of its argument. tan expects its argument to be in radians.
The tanh function returns the hyperbolic tangent of its argument. tanh expects its argument to be in radians. Use of functions and complex variables for airfoils
The operators in GNUPLOT are the same as the corresponding operators in the C programming language, except that all operators accept integer, real, and complex arguments, unless otherwise noted. The ** operator (exponentiation) is supported, as in FORTRAN.
Parentheses may be used to change order of evaluation.
The following is a list of all the binary operators and their usages:
Symbol Example Explanation ** a**b exponentiation * a*b multiplication / a/b division % a%b * modulo + a+b addition - a-b subtraction == a==b equality != a!=b inequality & a&b * bitwise AND ^ a^b * bitwise exclusive OR | a|b * bitwise inclusive OR && a&&b * logical AND || a||b * logical OR ?: a?b:c * ternary operation
(*) Starred explanations indicate that the operator requires integer arguments.
Logical AND (&&) and OR (||) short-circuit the way they do in C. That is, the second && operand is not evaluated if the first is false; the second || operand is not evaluated if the first is true.
The ternary operator evaluates its first argument (a). If it is true (non-zero) the second argument (b) is evaluated and returned, otherwise the third argument (c) is evaluated and returned.
The following is a list of all the unary operators and their usages:
Symbol Example Explanation - -a unary minus ~ ~a * one's complement ! !a * logical negation ! a! * factorial
(*) Starred explanations indicate that the operator requires an integer argument.
The factorial operator returns a real number to allow a greater range.
This implementation incorporates the capabiblity of nonlinear least squares fit by using the Marquardt-Levenberg-Algorithm. It may fit every user-defined function to any set of data pairs (x,y). x, y and the function's return type MUST be real! Any variable occuring in the function body may serve as fit parameter (fitting functions without adjustable parameters make no sense). The syntax is:
fit <function> <datafile> {using x:y{:dy}} <parameter file> or
fit <function> <datafile> {using x:y{:dy}} via <var1>, <var2>, ...
<function> is a previously user-defined function of the form: f(x) <datafile> is treated as in the plot-command. The default column for x is 1, for y is 2. They may be changed by the using x:y mechanism. The optional dy specifies a column containing individual uncertainties for each y-value. These will then be used as weights during the fit. If they aren't given all uncertainties are assumed equally distributed. The start parameters may be specified in a (load-) file wherein each line is of the form:
varname = value
(comments, separated by '#' and blank lines are also possible). The form
varname = value # FIXED
means that the variable is treated as a fixed parameter that is initialized but will not be adjusted. It is not necessary (but sometimes useful for clarity) to specify them at all. The keyword '# FIXED' has to appear in exactly this form. The other possibility of specifying start values is that the current value of a variable during the GNUPLOT session shall serve as start parameter. In this case the syntax including the via keyword may be used where only the adjustable variables' names must be given.
After each iteration step a detailed info is given about the fit's state both on the screen and on a logfile "fit.log". This file will never be erased but always appended so that the fit's history isn't lost. After each iteration step the fit may be interrupted by pressing ctrl-C (any key BUT ctrl-C under MSDOS). Then you have the possibility of stopping (and accepting the current parameter values) or continuing the fit or of executing a gnuplot command specified by an environment variable FIT_SCRIPT. E.g. a plot command or LOADing some file may be useful.
Special GNUPLOT variables:
FIT_INDEX: This variable always contains the current data point number
during execution starting with 1. You may use it in your fit
function to implement multiple-branch-fits.
FIT_SKIP: You may specify a positive integer to always skip i data points
during fitting. This increases execution speed by the
price of less exact results.
FIT_LIMIT: may be specified to change the default epsilon limit (1e-5).
When the sum of squared residuals changes between 2 iteration
steps by less than a factor of this number, the fit is
considered as 'converged'.
Environment variables:
FIT_LOG changes the logfile's path from './fit.log' (write permission
is necessary).
FIT_SCRIPT specifies a command to be executed after an user interrupt
Examples: f(x) = a*x**2 + b*x + c fit f(x) 'measured.dat' 'start.par' fit f(x) 'measured.dat' using 3:7 'start.par' fit f(x) './data/trash.dat' using 1:2:3 via a, b, c
SEE ALSO: update
The help command displays on-line help. To specify information on a particular topic use the syntax:
help {<topic>}
If <topic> is not specified, a short message is printed about GNUPLOT. After help for the requested topic is given, help for a subtopic may be requested by typing its name, extending the help request. After that subtopic has been printed, the request may be extended again, or simply pressing return goes back one level to the previous topic. Eventually, the GNUPLOT command line will return.
The if command allows commands to be executed conditionally.
Syntax:
if (<condition>) <command-line>
The <condition> will be evaluated, if it is true (non-zero), then the command(s) of the <command-line> will be executed. If the <condition> is false (equals zero), then the entire <command-line> is ignored. Note that use of ';' to allow multiple commands on the same line will NOT end the conditionalized commands.
Examples:
pi=3
if (pi!=acos(-1)) pause 0 "?Fixing pi!";pi=acos(-1);show variables
will display:
?Fixing pi!
Variables:
pi = 3.14159
or
if (1==2) pause 0 "Never see this";pause 0 "Or this either"
will not display anything.
The load command executes each line of the specified input file as if it had been typed in interactively. Files created by the save command can later be loaded. Any text file containing valid commands can be created and then executed by the load command. Files being loaded may themselves contain load (or call) commands. See comment for information about comments in commands.
The load command must be the last command on the line.
Syntax:
load "<input-file>"
The name of the input file must be enclosed in quotes.
Examples:
load 'work.gnu'
load "func.dat"
The load command is performed implicitly on any file names given as arguments to GNUPLOT. These are loaded in the order specified, and then GNUPLOT exits.
The call command is identical to the load command with one exception: you can have up to 10 additional parameters to the command (delimited according to the standard parser rules) which can be substituted into the lines read from the file. As each line is read from the called input-file it is scanned for the sequence $ (dollar-sign) followed by a digit (0-9). If found, the sequence is replaced by the corresponding parameter from the call command line. If the parameter was specified as a string in the call line, it is substituted without its enclosing quotes. $ followed by any character other than a digit will be that character. (E.g. use $$ to get a single $.) Providing more than 10 parameters on the call command line will cause an error. A parameter that was not provided, substitutes as nothing. Files being called may themselves contain call or load commands.
The call command must be the last command on the line.
Syntax:
call "<input-file>" <parameter-0> <parm-1> ... <parm-9>
The name of the input file must be enclosed in quotes.
Examples:
if the file 'calltest.gp' contains the line:
pause 0 "p0=$0 p1=$1 p2=$2 p3=$3 p4=$4 p5=$5 p6=$6 p7=x$7x"
entering the command:
call 'calltest.gp' "abcd" 1.2 + "'quoted'" -- "$2"
will display:
p0=abcd p1=1.2 p2=+ p3='quoted' p4=- p5=- p6=$2 p7=xx
pause
The pause command displays any text associated with the command and
then waits a specified amount of time or until the carriage return is
pressed. pause is especially useful in conjunction with load files.
Syntax:
pause <time> {"<string>"}
<time> may be any integer constant or expression. Choosing -1 will
wait until a carriage return is hit, zero (0) won't pause at all, and
a positive integer will wait the specified number of seconds.
Note: Since pause is not part of the plot it may interact with
different device drivers differently (depending upon how text and
graphics are mixed).
Examples:
pause -1 # Wait until a carriage return is hit
pause 3 # Wait three seconds
pause -1 "Hit return to continue"
pause 10 "Isn't this pretty? It's a cubic-spline."
plot
plot and splot are the primary commands of the program. They plot
functions and data in many, many ways. plot is used to plot 2-d
functions and data, while splot plots 3-d surfaces and data.
Syntax:
plot {ranges} {<function> | {"<datafile>" {using ...}}}
{title} {style} {, <function> {title} {style}...}
splot {ranges} {<function> | {"<datafile>" {index i} {using ...}}}
{title} {style} {, <function> {title} {style}...}
where either a <function> or the name of a data file enclosed in quotes is
supplied. A function is a mathematical expression, or a pair (plot) or
triple (splot) of mathematical expressions in the case of parametric
functions. User-defined functions and variables may also be defined here.
plot and splot commands can be as simple as
plot sin(x)
and
splot x * y
or as complex as (!)
plot [t=1:10] [-pi:pi*2] tan(t), "data.1" using 2:3 with lines,
t**2 with points
data-file
errorbars
parametric
ranges
index
style
title
data-file
Discrete data contained in a file can be displayed by specifying the
name of the data file (enclosed in quotes) on the plot or splot
command line. Data files should contain one data point per line.
Lines beginning with # (or ! on VMS) will be treated as comments
and ignored. For plots, each data point represents an (x,y)
pair. For splots, each point is an (x,y,z) triple. For plots with
error bars (see plot errorbars), each data point is either
(x,y,ydelta), (x,y,ylow,yhigh), (x,y,xdelta), (x,y,xlow,xhigh), or
(x,y,xlow,xhigh,ylow,yhigh). In all cases, the numbers on each
line of a data file must be separated by blank space. This blank
space divides each line into columns.
For plots the x value may be omitted, and for splots the x
and y values may be omitted. In either case the omitted values are
assigned the current coordinate number. Coordinate numbers start at 0
and are incremented for each data point read.
To specify other formats, see plot datafile using.
In the plot command, blank lines in the data file cause a break in
the plot. There will be no line drawn between the preceding and
following points if the plot style is lines or linespoints (see
plot style). This does not change the plot style, as would plotting
the data as separate curves.
This example compares the data in the file population.dat to a
theoretical curve:
pop(x) = 103*exp((1965-x)/10)
plot [1960:1990] 'population.dat', pop(x)
The file population.dat might contain:
# Gnu population in Antarctica since 1965
1965 103
1970 55
1975 34
1980 24
1985 10
When a data file is plotted, samples and isosamples are ignored.
Curves plotted using the plot command are automatically extended to
hold the entire curve. Similarly grid data plotted using the splot
command is automatically extended, using the assumption that isolines
are separated by blank lines (a line with only a CR/LF in it).
Implicitly, there are two types of 3-d datafiles. If all the isolines
are of the same length, the data is assumed to be a grid data, i.e.,
the data has a grid topology. Cross isolines in the other parametric
direction (the ith cross isoline passes through the ith point of all the
provided isolines) will also be drawn for grid data. (Note contouring
is available for grid data only.) If all the isolines are not of the
same length, no cross isolines will be drawn and contouring that data
is impossible.
For splot, data files may contain more than one mesh and by default
all meshes are plotted. Meshes are separated from each other, in the
file, by double blank lines. To control and splot a single mesh from
a multi mesh file, use the index modifier. See splot index for more.
For splot if 3-d datafile and using format (see splot datafile using)
specify only z (height field), a non parametric mode must be specified.
If, on the other hand, x, y, and z are all specified, a parametric
mode should be selected (see set parametric) since data is defining a
parametric surface.
A simple example of plotting a 3-d data file is
set parametric
splot 'glass.dat'
or
set noparametric
splot 'datafile.dat'
where the file datafile.dat might contain:
# The valley of the Gnu.
10
10
10
10
5
10
10
1
10
10
0
10
Note datafile.dat defines a 4 by 3 grid ( 4 rows of 3 points each ).
Rows are separated by blank lines.
On some computer systems with a popen function (UNIX), the datafile
can be piped through a shell command by starting the file name
with a '<'. For example:
pop(x) = 103*exp(-x/10)
plot "< awk '{print $1-1965, $2}' population.dat", pop(x)
would plot the same information as the first population example
but with years since 1965 as the x axis. If you want to execute
this example, you have to delete all comments from the data file
above or substitute the following command for the first part of the
command above (the part up to the comma):
plot "< awk '$0 !~ /^#/ {print $1-1965, $2}' population.dat"
It is also possible to apply a single function to the "y" value only,
e.g.
plot 'population.dat' thru p(x)
For more information about 3-d plotting, see splot.
Simple Plot Demos ,
Non-parametric splot demos , and
Parametric splot demos.
using
The format of data within a file can be selected with the using
option. An explicit scanf string can be used, or simpler column
choices can be made.
Syntax:
plot "datafile" { using { <ycol> |
<xcol>:<ycol> |
<xcol>:<ycol>:<ydelta> |
<xcol>:<ycol>:<xdelta> |
<xcol>:<ycol>:<boxwidth> |
<xcol>:<ycol>:<ylow>:<yhigh> |
<xcol>:<ycol>:<xlow>:<xhigh> |
<xcol>:<ycol>:<xdelta>:<ydelta> |
<xcol>:<ycol>:<ydelta>:<boxwidth> |
<xcol>:<ycol>:<ylow>:<yhigh>:<boxwidth> |
<xcol>:<ycol>:<xlow>:<xhigh>:<ylow>:<yhigh>}
{"<scanf string>"} } ...
and
splot "datafile" { using { <xcol>:<ycol>:<zcol> | <zcol> }
{"<scanf string>"} } ...
<xcol>, <ycol>, and <zcol> explicitly select the columns to plot from
a space or tab separated multicolumn data file. If only <ycol> is
selected for plot, <xcol> defaults to 1. If only <zcol> is selected
for splot, then only that column is read from the file. An <xcol> of
0 forces <ycol> to be plotted versus its coordinate number. <xcol>,
<ycol>, and <zcol> can be entered as constants or expressions.
If x, y and/or z is time data (dates-times), the columns occupied by
the time (any character, spaces included, is allowed in format string)
counts for one column. The "scanf-string" will not work with timeseries.
See also set timefmt.
Time Data Demo
If yerrorbars (see also plot errorbars) are used for plots,
ydelta (for example, a +/- error) should be provided as the third
column, or ylow and yhigh as third and fourth columns.
If xerrorbars (see also plot errorbars) are used for plots,
xdelta (for example, a +/- error) should be provided as the third
column, or xlow and xhigh as third and fourth columns.
If xyerrorbars or boxxyerrorbars (see also plot errorbars) are used for
plots, xlow and xhigh may be provided as third and fourth columns and
ylow and yhigh may be provided as fifth and sixth columns. It is also
possible to have xdelta and ydelta in the third and fourth columns,
respectively.
If boxes are used for plots, the third column is used to
specify the width of the box. If boxerrorbars are used, the fourth column (if
"ydelta" is third col), or the fifth column (if "ylow" and "yhigh" are
third and fourth cols) may be used for the box width. See boxerrorbars or
set style for more details.
Note that boxerrorbars is only used for data
with errors in y. Each box starts at the x axis (boxxyerrorbars has different
behavior).
Errorbar demos.
Scanf strings override any <xcol>:<ycol>(:<zcol>) choices, except for
ordering of input, e.g.,
plot "datafile" using 2:1 "%lf%*lf%lf"
causes the first column to be y and the third column to be x.
If the scanf string is omitted, the default is generated based on the
<xcol>:<ycol>(:<zcol>) choices. If the using option is omitted, "%lf%lf"
is used for plot ("%lf%lf%lf%lf" for errorbars plots) and "%lf%lf%lf" is
used for splot.
Examples:
plot "MyData" using "%*lf%lf%*20[^\n]%lf" with lines
Data are read from the file "MyData" using the format
"%*lf%lf%*20[^\n]%lf". The meaning of this format is: "%*lf" ignore the
first number, "%lf" then read in the second and assign to x,
"%*20[^\n]" then ignore 20 non-newline characters, "%lf" then read in
the y value.
n=3;
plot "MyData", "MyData" using n
causes GNUPLOT to plot the second and third columns of MyData versus
the first column. The command 'n=4; replot' would then plot the second
and fourth columns of MyData versus the first column.
splot "glass.dat" using 1
causes GNUPLOT to plot the first coordinate of the points of glass.dat
as the z coordinate while ignoring the other two coordinates.
Note: GNUPLOT first reads a line of the data file into a buffer and
then does a
sscanf(input_buffer, scanf_string, &x, &y{, &z});
where 'x', 'y', and 'z' are of type 'float'. Any scanf string that
specifies two (three for splot, three to six for errorbars) float
numbers may be used.
Using Demos.
errorbars
Error bars are supported for 2-d data file plots by reading one to
four additional columns specifying ydelta or ylow and yhigh for
yerrorbars or xdelta or xlow and xhigh for xerrorbars or xdelta, ydelta
or xlow, xhigh, ylow, yhigh for xyerrorbars or boxxyerrorbars.
No support exists for any error bars for splots.
In the default situation, GNUPLOT expects to see three or six
numbers on each line of the data file, either (x, y, ydelta),
(x, y, ylow, yhigh), (x, y, xdelta), (x, y, xlow, xhigh),
(x, y, xdelta, ydelta), or (x, y, xlow, xhigh, ylow, yhigh). The
x coordinate must be specified. The order of the numbers must be
exactly as given above. Data files in this format can easily be
plotted with error bars:
plot "data.dat" with errorbars (or yerrorbars)
plot "data.dat" with xerrorbars
plot "data.dat" with xyerrorbars
plot "data.dat" with yerrorbars
The y-error bar is a vertical line plotted from (x, ylow) to (x,
yhigh). If ydelta is specified instead of ylow and yhigh,
ylow=y-ydelta and yhigh=y+ydelta are derived. If there
are only two numbers on the line, yhigh and ylow are both set to
y. The x-error bar is a horizontal line computed in the same fashion.
To get lines plotted between the data points, plot the data file
twice, once with errorbars and once with lines.
If autoscaling is on, the x and/or y range will be adjusted to fit the
error bars.
The using option may be used to specify how columns of the data file
are to be assigned to x, y, ydelta, ylow and yhigh, xdelta, xlow and xhigh.
The x column must
be provided and both the x and y columns must appear before the
errorbar columns. If three column numbers are given, they are x, y,
and ydelta or xdelta. If four columns are given, they are x, y, ylow,
and yhigh or x, y, xlow, and xhigh or x, y, xdelta, ydelta.
Examples:
plot "data.dat" using 1:2:3:4 with errorbars (or yerrorbars)
plot "data.dat" using 3:2:6 with xerrorbars
plot "data.dat" using 3:4:8:7 with xyerrorbars
The first example reads, x, y, ylow, and yhigh, from columns 1, 2, 3,
and 4. This is equivalent to the default. The second example reads x
from the third column, y from second and xdelta from the sixth column.
The third example reads x from the third column, y from the fourth,
xdelta from the eighth, and ydelta from seventh columns.
Errorbar demos.
See also plot using and plot style.
parametric
When in parametric mode (set parametric) mathematical expressions must
be given in pairs for plot and in triplets for splot:
plot sin(t),t**2
or
splot cos(u)*cos(v),cos(u)*sin(v),sin(u)
Data files are plotted as before, except any preceding parametric
function must be fully specified before a data file is given as a
plot. In other words, the x parametric function (sin(t) above) and
the y parametric function (t**2 above) must not be interrupted with
any modifiers or data functions; doing so will generate a syntax error
stating that the parametric function is not fully specified.
Ranges take on a different meaning when in parametric mode. The first
range on the plot command is the trange, the next is the xrange,
and the last is the yrange. For splot the order is urange,
vrange, xrange, yrange, and finally zrange. The following
plot command shows setting the trange to [-pi:pi], the xrange to
[-1.3:1.3] and the yrange to [-1:1] for the duration of the plot:
plot [-pi:pi] [-1.3:1.3] [-1:1] sin(t),t**2
Other modifiers, such as with and title, may be specified only
after the parametric function has been completed:
plot sin(t),t**2 title 'Parametric example' with linespoints
ranges
The optional range specifies the region of the plot that will be
displayed.
Ranges may be provided on the plot and splot command line and
affect only that plot, or in the set xrange, set yrange, etc.,
commands, to change the default ranges for future plots.
Syntax:
[{<dummy-var> =} {<xmin> : <xmax>}] { [{<ymin> : <ymax>}] }
where <dummy-var> is the independent variable (the defaults are x and
y, but this may be changed with set dummy) and the min and max
terms can be constant expressions. If only one value is provided
(as in: set yrange [0:]) the range in the opposite direction is
unaffected (or still autoscaled). To set a range back to autoscale
give a star as the value (set yrange [*:] turns autoscaling in
the ymin direction on).
Both the min and max terms are optional. The ':' is also optional
if neither a min nor a max term is specified. This allows '[ ]' to
be used as a null range specification.
Specifying a range in the plot command line turns autoscaling for
that axis off for that plot. Using one of the set range commands
turns autoscaling off for that axis for future plots, unless changed
later. (See set autoscale).
With time data, provide the ranges in the samme manner as in the datafile
within quotes (uses the timefmt string to read the value).
Examples:
This uses the current ranges:
plot cos(x)
This sets the x range only:
plot [-10:30] sin(pi*x)/(pi*x)
This is the same, but uses t as the dummy-variable:
plot [t = -10 :30] sin(pi*t)/(pi*t)
This sets both the x and y ranges:
plot [-pi:pi] [-3:3] tan(x), 1/x
This sets only the y range, and turns off autoscaling on both axes:
plot [ ] [-2:sin(5)*-8] sin(x)**besj0(x)
This sets xmax and ymin only:
plot [:200] [-pi:] exp(sin(x))
This sets the x, y, and z ranges:
splot [0:3] [1:4] [-1:1] x*y
Timeseries (timefmt="%d/%m/%y %H:%M"):
set xrange ["1/6/93 12:00":"5/6/93 12:00"]
index
Splotting of multi mesh data files can be controlled via the index modifier.
A data file can contain more than one mesh, and in that case all meshes
in the file will be splotted by default. Meshes are separated from each
other, in the data file, by double blank lines. To splot a single mesh in
a multi mesh file use the index modifier which specify which mesh to splot.
First mesh is mesh 0.
Example:
splot "data1" index 2 with points
will splot the third mesh in file data1 with points.
splot with indices demo.
style
Plots may be displayed in one of thirteen styles: lines, points,
linespoints, impulses, dots, {x,y,xy}errorbars, steps, fsteps,
boxes, boxerrorbars, or boxxyerrorbars. The lines style
connects adjacent points with lines.
The points style displays a small symbol at each point.
The linespoints style does both lines and points.
The impulses style displays a vertical line from the x axis
(or from the grid base for splot) to each point. The dots style
plots a tiny dot at each point; this is useful for
scatter plots with many points.
The errorbars (or yerrorbars) and xerrorbars styles are only relevant to
2-d data file plotting. It
is treated like points for splots and function plots. For data
plots, errorbars is like points, except that a vertical or
horizontal error bar is also drawn: for each point (x,y), a line is
drawn from (x,ylow) to (x,yhigh) or (xlow,y) to (xhigh,y). A tic mark is
placed at the ends of the error bar. The (ylow, yhigh) or (xlow,xhigh)
values are read from the data file's columns, as specified with the using
option to plot. See plot errorbars for more information.
The boxes style is only relevant to 2-d plotting. Another style
called boxerrorbars is also available and is only relevant to 2-d
data file plotting. This style is a combination of the boxes and
errorbars styles. The boxes style draws a box centred about
the given x coordinate from the yaxis to the given y coordinate.
The width of the box is obtained in one of three ways. First, if a
data file has a fifth column, this will be used to set the width of
the box. Columns 3 and 4 (for boxerrorbars) are necessary but
ignored in this instance. Secondly, if a width has been set using
the set boxwidth command, this will be used. Otherwise the width
of each box will be calculated automatically so that it touches the
adjacent boxes.
The boxes style is only relevant to 2-d plotting. It draws
a box centred about the given x coordinate from the yaxis to the given
y coordinate. The width of the box is obtained in one of three
ways. If a data file has a third column, this will be used to set
the width of the box. Otherwise, if a width has been set using the
set boxwidth command, this will be used. Otherwise the width of each
box will be calculated automatically so that it touches the adjacent
boxes. Another style called boxerrorbars is also available and is
only relevant to 2-d data file plotting. This style is a combination
of the boxes and errorbars styles. The boxwidth will come from the fourth
column if the y errors are in the form of "ydelta" and the boxwidth was not
previously set equal to -2.0 (set boxwidth -2.0) or from the fifth
column if the y errors are in the form of "ylow yhigh". The boxwidth = -2.0 is
for the special case of 4-column data and the y errors are in the form of
"ylow yhigh". The boxwidth will be calculated automatically so that each box
touches the adjacent boxes. The width will also be automatically calculated
if 3-column data is used. The boxxyerrorbars
style is like the xyerrorbars option except that a box with width
(xhigh-xlow) and height (yhigh-ylow) is drawn instead of a cross of that size.
For 2-d data with more than two columns, gnuplot will be picky about the
allowed plot styles. For three columns only xerrorbars, boxes,
errorbars (or yerrorbars), and boxerrorbars are allowed. If another plot
style is used,
the style will be changed to yerrorbars. The boxerrorbars style will
calculate the boxwidth automatically. For four columns only xerrorbars,
xyerrorbars, boxxyerrorbars, boxerrorbars, and errorbars (or
yerrorbars) are allowed. An illegal plot style will be changed to
yerrorbars. Five column data allows only the boxerrorbars style. An
illegal style will be changed to boxerrorbars before plotting. Six and
seven column data only allows the xyerrorbars and boxxyerrorbars styles.
Illegal styles will be changed to xyerrorbars before plotting. Use the
using option for plot to setup the correct number of columns for the
style you want.
The steps and fsteps styles is only relevant to 2-d plotting.
The steps style connects consecutive points with two line segments:
the first from (x1,y1) to (x2,y1) and the second from (x2,y1) to (x2,y2).
The fsteps: (x1,y1) to (x1,y2) and (x1,y2) to (x2,y2).
Steps Demo.
Default styles are chosen with the set function style and
set data style commands.
By default, each function and data file will use a different
line type and point type, up to the maximum number of available
types. All terminal drivers support at least six different point
types, and re-use them, in order, if more than six are required.
The LaTeX driver supplies an additional six point types (all variants
of a circle), and thus will only repeat after twelve curves are
plotted with points.
If desired, the style and (optionally) the line type and point type
used for a curve can be specified.
Syntax:
with <style> {<linetype> {<pointtype>}}
where <style> is either lines, points, linespoints, impulses,
dots, steps, fstepsm {x,y,xy}errorbars, boxes, boxerrorbars,
or boxxyerrorbars. The <linetype> and <pointtype> are
positive integer constants or expressions and specify the line type
and point type to be used for the plot. Line type 1 is the first line
type used by default, line type 2 is the second line type used by
default, etc.
Examples:
This plots sin(x) with impulses:
plot sin(x) with impulses
This plots x*y with points, x**2 + y**2 default:
splot x*y w points, x**2 + y**2
This plots tan(x) with the default function style, "data.1" with lines:
plot [ ] [-2:5] tan(x), "data.1" with l
This plots "leastsq.dat" with impulses:
plot 'leastsq.dat' w i
This plots the data file 'population' with boxes:
plot "population" with boxes
This plots "exper.dat" with errorbars and lines connecting the points:
plot 'exper.dat' w lines, 'exper.dat' w errorbars
Here 'exper.dat' should have three or four data columns.
This plots x**2 + y**2 and x**2 - y**2 with the same line type:
splot x**2 + y**2 with line 1, x**2 - y**2 with line 1
This plots sin(x) and cos(x) with linespoints, using the
same line type but different point types:
plot sin(x) with linesp 1 3, cos(x) with linesp 1 4
This plots file "data" with points style 3:
plot "data" with points 1 3
Note that the line style must be specified when specifying the point
style, even when it is irrelevant. Here the line style is 1 and the
point style is 3, and the line style is irrelevant.
See set style to change the default styles.
title
A title of each plot appears in the key. By default the title is
the function or file name as it appears on the plot command line.
The title can be changed by using the title option. This option
should precede any with option.
Syntax:
title "<title>"
where <title> is the new title of the plot and must be enclosed in
quotes. The quotes will not be shown in the key. Special characters
may be given as backslash and their octal value (\345), \t is
anderstood.
Examples:
This plots y=x with the title 'x':
plot x
This plots the "glass.dat" file with the title 'surface of revolution':
splot "glass.dat" title 'surface of revolution'
This plots x squared with title "x^2" and "data.1" with title
'measured data':
plot x**2 title "x^2", "data.1" t 'measured data'
The title can be omitted from the key with the "notitle" option for
plot and splot. This can be useful when some curves
are plotted solely for decoration; for example, if one wanted a
circular border for a polar plot, he could say:
Example:
set polar
plot my_function(x), 1 notitle
This would generate a key entry for "my_function" but not for "1".
See the poldat.dem example.
print
The print command prints the value of <expression> to the screen.
Syntax:
print <expression>
See expressions.
pwd
The pwd command prints the name of the working directory to the screen.
Syntax:
pwd
quit
The exit and quit commands and END-OF-FILE character will exit
GNUPLOT. All these commands will clear the output device (as the
clear command does) before exiting.
replot
The replot command without arguments repeats the last plot or splot
command. This can be useful for viewing a plot with different set
options, or when generating the same plot for several devices.
Arguments specified after a replot command will be added onto the last
plot (splot) command (with an implied ',' separator) before it is
repeated. replot accepts the same arguments as the plot (splot)
commands except that ranges cannot be specified.
See command line-editing for ways to edit the last plot
(splot) command.
reread
The reread command causes the current gnuplot command file, as specified
by a load command or on the command line, to be reset to its starting
point before further commands are read from it. This essentially implements
an endless loop of the commands from the beginning of the command file to
the reread command. The reread command has no effect if input from
standard input.
Reread Animation
reset
The reset command causes all options that can be set with the
set-command to take on their default values. The only exceptions are
that the terminal set with set term and the output file set with
set output are left unchanged. This command is useful e.g. to restore
the default settings at the end of a command file, or to return to a
defined state after lots of settings have been changed within a command
file. Please refer to the set command to see the default values that
the respective options take.
save
The save command saves user-defined functions, variables, set
options or all three plus the last plot (splot) command to the
specified file.
Syntax:
save {<option>} "<filename>"
where <option> is functions, variables or set. If no option is
used, GNUPLOT saves functions, variables, set options and the last plot
(splot) command.
saved files are written in text format and may be read by the load
command.
The filename must be enclosed in quotes.
Examples:
save "work.gnu"
save functions 'func.dat'
save var 'var.dat'
save set "options.dat"
set-show
The set command sets LOTS of options.
The show command shows their settings. show all shows all the
settings.
angles
arrow
autoscale
border
boxwidth
clabel
clip
cntrparam
contour
data style
dgrid3d
dummy
format
function style
functions
grid
hidden3d
isosamples
key
keytitle
label
logscale
mapping
offsets
output
parametric
pointsize
polar
rrange
samples
size
style
surface
terminal
tics
time
timefmt
title
trange
urange
variables
view
vrange
xdata
xlabel
xmargin
xrange
xtics
mxtics
mytics
xdtics
xmtics
xzeroaxis
ydata
ylabel
yrange
ytics
ydtics
ymtics
yzeroaxis
zdata
zero
zeroaxis
zlabel
zrange
ztics
zdtics
zmtics
angles
By default, GNUPLOT assumes the independent variable in polar plots
is in units of radians. If set angles degrees is specified before
set polar then the default range is [0:360] and the independent
variable has units of degrees. This is particularly useful for
plots of data files. The angle setting also hold for the 3-d
mapping as set via the set mapping command.
Syntax:
set angles { degrees | radians }
show angles
arrow
Arbitrary arrows can be placed on a plot using the set arrow
command.
Syntax:
set arrow {<tag>} {from <sx>,<sy>{,<sz>}}
{to <ex>,<ey>{,<ez>}} {{no}head}
set noarrow {<tag>}
show arrow
Unspecified coordinates default to 0. The x, y, and z values are in
the graph's coordinate system. The z coordinate is only used in
splot commands. <tag> is an integer that identifies the arrow. If no
tag is given, the lowest unused tag value is assigned automatically.
The tag can be used to delete or change a specific arrow. To change
any attribute of an existing arrow, use the set arrow command with
the appropriate tag, and specify the parts of the arrow to be
changed. Specifying nohead requests the arrow be drawn without a head
(yielding a line segment). By default, arrows have heads.
Arrows outside the plotted boundaries are permitted but may cause
device errors.
Examples:
To set an arrow pointing from the origin to (1,2), use:
set arrow to 1,2
To set an arrow from (-10,4,2) to (-5,5,3), and tag the arrow number
3, use:
set arrow 3 from -10,4,2 to -5,5,3
To change the preceding arrow begin at 1,1,1, without an arrow head,
use:
set arrow 3 from 1,1,1 nohead
To delete arrow number 2 use:
set noarrow 2
To delete all arrows use:
set noarrow
To show all arrows (in tag order) use:
show arrow
autoscale
Auto scaling may be set individually on the x, y or z axis
or globally on all axes. The default is to autoscale all axes.
When autoscaling, the plot range is automatically computed and the
dependent axis (y for a plot and z for splot) is scaled to
include the range of the function or data being plotted.
If autoscaling of the dependent axis (y or z) is not set, the
current y or z range is used.
See set yrange or set zrange.
Autoscaling the independent variables (x for plot and x,y for
splot) is a request to set the domain to match any data file being
plotted. If there are no data files then autoscaling an independent
variable has no effect. In other words, in the absence of a data
file, functions alone do not affect the x range (or the y range if
plotting z = f(x,y)).
See set xrange, or set yrange.
The behavior of autoscaling remains consistent in parametric mode,
however, there are more dependent variables and hence more control
over x, y, and z plot scales. In parametric mode, the independent or
dummy variable is t for plots and u,v for splots. Autoscale in
parametric mode, then, controls all ranges (t, u, v, x, y, and z) and
allows x, y, and z to be fully autoscaled.
See set parametric.
Syntax:
set autoscale <axes>
set noautoscale <axes>
show autoscale
where <axes> is either x, y, z or xy. If <axes> is not given
then all axes are assumed.
Examples:
This sets autoscaling of the y axis. x axis autoscaling is not
affected.
set autoscale y
This sets autoscaling of the x and y axes.
set autoscale xy
This sets autoscaling of the x, y and z axes.
set autoscale
This disables autoscaling of the x, y and z axes.
set noautoscale
This disables autoscaling of the z axis only.
set noautoscale z
parametric mode
When in parametric mode (set parametric) the xrange is as
fully scalable as the yrange. In other words, in parametric
mode the x axis can be automatically scaled to fit the range
of the parametric function that is being plotted. Of course,
the y axis can also be automatically scaled just as in the
non-parametric case. If autoscaling on the x axis is not set,
the current x range is used.
When there is a mix of data files and functions, the xrange of
the functions is selected as that of the data files if autoscale
is true for x. While this keeps the behavior compatible with
non-parametric plotting, it may not be retained in the future.
The problem is that, in parametric mode, the x and y ranges are
not as distinguishable as in the non-parametric mode and this
behavior may not be the most useful.
For completeness a last command set autoscale t is accepted.
However, the effect of this "scaling" is very minor. When
GNUPLOT determines that the t range would be empty it makes a
small adjustment if autoscaling is true. Otherwise, GNUPLOT
gives an error. Such behavior may, in fact, not be very useful
and the command set autoscale t is certainly questionable.
splot extends the above idea similarly. If autoscaling is set then
x, y, and z ranges are computed and each axis scaled to fit the
resulting data.
border
The set border and set noborder commands controls the display of
the plot borders for the plot commands. The borders
are encoded in a four bit integer:
SOUTH 0th bit
WEST 1st bit
NORTH 2nd bit
EAST 3rd bit
To facilitate two y-scales, the tic marks and labels will only be
written to the EAST and NORTH borders if the opposite border is off.
Syntax:
set border (turns on all borders)
set border 3 (only SOUTHWEST borders)
set border 12 (only NORTHEAST borders with tics on top and right)
set noborder
show border
e.g
Borders Demo.
boxwidth
The set boxwidth command is used to set the default width of
boxes in the boxes and boxerrorbars styles.
If a data file is plotted without the width being specified in the
third to fifth columns, or a function is plotted, the width of each box is
set by the set boxwidth command. If a width is given after the
set boxwidth command then this is used as the width. Otherwise
the width of each box will be calculated automatically so that
it touches the adjacent boxes. Four-column data may have the width be
calculated automatically if the width is first set to -2.0. Otherwise, the
fourth column will be interpreted as the box width. See boxerrorbars or
set style for more details.
Syntax:
set boxwidth {<width>}
show boxwidth
To set the box width to automatic use the command
set boxwidth
set boxwidth -2 (4-col data)
clabel
GNUPLOT will vary the linetype used for each contour level
when clabel is set. When this option on (the default), a
legend labels each linestyle with the z level it represents.
Syntax:
set clabel
set noclabel
show clabel
clip
GNUPLOT can clip data points and lines that are near the boundaries
of a plot.
Syntax:
set clip <clip-type>
set noclip <clip-type>
show clip
Three clip types are supported by GNUPLOT: points, one, and two.
One, two, or all three clip types may be active for a single plot.
The points clip type forces GNUPLOT to clip (actually, not plot at
all) data points that fall within but too close to the boundaries
(this is so the large symbols used for points will not extend outside
the boundary lines). Without clipping points near the boundaries may
look bad; try adjusting the x and y ranges.
Setting the one clip type causes GNUPLOT to plot the line segments
which have only one of the two endpoints within the plotting region.
Only the in-range portion of the line is drawn. The alternative is to
not draw any portion of the line segment.
Some lines may have both endpoints out of range, but pass through the
plotting area. Setting the two clip-type allows the visible portion
of these lines to be drawn.
In no case is a line drawn outside the plotting area.
The defaults are noclip points, clip one, and noclip two.
To check the state of all forms of clipping, use
show clip
For backward compatibility with older versions, the following forms
are also permitted.
set clip
set noclip
set clip is synonymous with set clip points. set noclip turns
off all three types of clipping.
cntrparam
Sets the different parameters for the contouring plot (see also contour).
Syntax:
set cntrparam { { linear | cubicspline | bspline } |
points <n> |
order <n> |
levels { [ auto ] <n> |
discrete <z1>,<z2>, ... |
incremental {<start>, <incr>{, <end>} } }
Examples:
set cntrparam bspline
set cntrparam points 7
set cntrparam order 10
set cntrparam levels auto 5 # 5 automatic levels
set cntrparam levels discrete .1,1/exp(1),.9 # 3 discrete at .1,.37,.9
set cntrparam levels incremental 0,.1,.4
# 5 incremental levels at 0, .1, .2, .3 and .4
set cntrparam levels 10
# sets n = 10 retaining current setting of auto, discr. and
# increment's start and increment value, while changing end
set cntrparam levels incremental 100,50
# set start = 100 and increment = 50, retaining n levels
This command controls the way contours are plotted. <n> should be an
integral constant expression and <z1>, <z2> any constant expressions.
The parameters are:
linear, cubicspline, bspline - Controls type of approximation or
interpolation. If linear, then the contours are drawn piecewise
linear, as extracted from the surface directly. If cubicspline, then
piecewise linear contours are interpolated to form a somewhat smoother
contours, but which may undulate. The third option is the uniform
bspline, which only approximates the piecewise linear data but is
guaranteed to be smoother.
points - Eventually all drawings are done with piecewise linear
strokes. This number controls the number of points used to
approximate a curve. Relevant for cubicspline and bspline modes
only.
order - Order of the bspline approximation to be used. The bigger this
order is, the smoother the resulting contour. (Of course, higher order
bspline curves will move further away from the original piecewise linear
data.) This option is relevant for bspline mode only. Allowed values are
integers in the range from 2 (linear) to 10.
levels - Number of contour levels, 'n'. Selection of the levels is
controlled by 'auto' (default), 'discrete', and 'incremental'. For 'auto',
if the surface is bounded by zmin and zmax then contours will be
generated from zmin+dz to zmax-dz in steps of size dz, where
dz = (zmax - zmin) / (levels + 1). For 'discrete', contours will be
generated at z = z1, z2 ... as specified. The number of discrete levels
is limited to MAX_DISCRETE_LEVELS, defined in plot.h to be 30. If
'incremental', contours are generated at <n> values of z beginning at
<start> and increasing by <increment>.
Contours Demo and
contours with User Defined Levels.
contour
Enable contour drawing for surfaces. This option is available for splot
only.
Syntax:
set contour { base | surface | both }
set nocontour
If no option is provided to set contour, the default is base.
The three options specify where to draw the contours: base draws
the contours on the grid base where the x/ytics are placed, surface
draws the contours on the surfaces themselves, and both draws the
contours on both the base and the surface.
See also set cntrparam for the parameters that affect the drawing of
contours.
Contours Demo and
contours with User Defined Levels.
data style
The set data style command changes the default plotting style
for data plots.
Syntax:
set data style
show data style
set data style <style-choice>
In the first case, set data style returns the possible style
choices: lines, points, linespoints, dots, steps,
impulses, {x,y,xy}errorbars, boxes, boxerrorbars or
boxxyerrorbars. show data style shows the current default plotting
style for data. set data style dots would actually change the default
plotting style. See also plot.
dgrid3d
Enables and sets the different parameters for non grid to grid data mapping.
Syntax:
set dgrid3d {,{<row_size>}{,{<col_size>}{,<norm>}}}
set nodgrid3d
Examples:
set dgrid3d 10,10,2
set dgrid3d ,,4
The first selects a grid of size 10 by 10 to be constructed and the use
of L2 norm in the distance computation. The second only modifies the norm
to be used to L4.
By default this option is disabled. When enabled, 3d data read from a file
is always treaded as a scattered data set. A grid with dimensions derived
from a bounding box of the scattered data and size as specified by the
row/col_size above is created for plotting and contouring. The grid is
equally spaced in x and y while the z value is computed as a weighted
average of the scattered points distance to the grid points. The closer
the scatter points to a grid point are the more effect they have on that
grid point. The third, norm, parameter controls the "meaning" of the
distance, by specifying the distance norm. This distance computation
is optimized for powers of 2 norms, specifically 1, 2, 4, 8, and 16, but
any nonnegative integer can be used.
This dgrid3d option is a simple low pass filter that converts scattered data
to a grid data set. More sophisticated approaches to this problem exists and
should be used as a preprocess to and outside gnuplot if this simple solution
is found inadequate.
Dgrid3d Demo.
dummy
By default, GNUPLOT assumes that the independent variable for the
plot command is x, and the independent variables for the splot
command are x and y. They are called the dummy variables because it
is just a notation to indicate the independent variables.
The set dummy command changes these default dummy variable names.
For example, it may be more convenient to call the dummy variable t
when plotting time functions:
set dummy t
plot sin(t), cos(t)
Syntax:
set dummy <dummy-var>{,<dummy-var>}
show dummy
Examples:
set dummy u,v
set dummy ,s
to set both dummy variables to u and v or set only the second
variable to s.
The set parametric command also changes the dummy variables (to t
for plot and u,v for splots).
format
The format of the tic-mark labels can be set with the set format
command. The default format for both axes is "%g", but other formats
such as "%.2f" or "%3.0fm" are often desirable. Anything accepted by
printf when given a double precision number, and then accepted by the
terminal, will work. In particular, the formats f, e, and g will work,
and the d, o, x, c, s, and u formats will not work. If data type for the
axis is date/time, the format string must contain valid codes for the
strftime function (do: man strftime). It's recommended to stick to the
conversion codes accepted by the set timefmt command. If the format
string looks like a floating point format, then gnuplot tries to construct
a reasonable format.
Syntax:
set format {<axes>} {"<format-string>"}
show format
where <axes> is either x, y, z, xy, or nothing (which is the
same as xy). The length of the string representing a ticmark (after
formatting with printf) is restricted to 100 characters. If the
format string is omitted, the format will be returned to the default
"%g". For LaTeX users, the format "$%g$" is often desirable. If the
empty string "" is used, no label will be plotted with each tic,
though the tic mark will still be plotted. To eliminate all tic marks,
use set noxtics or set noytics.
For plot newlines (\n) is accepted in the xaxis format string, and
for splot newlines is allowed for both x- and yaxis format strings.
See also set xtics and set ytics for more control over tic labels.
function style
The set function style command changes the default plotting style
for functions.
Syntax:
set function style
show function style
set function style <style-choice>
In the first case, set function style returns the possible style
choices: lines, points, linespoints, dots, steps,
impulses, {x,y,xy}errorbars, boxes, boxerrorbars, or
boxxyerrorbars.
show function style shows the current default plotting style for
functions. set function style linespoints would actually change
the default plotting style. See also plot.
functions
The show functions command lists all user-defined functions and
their definitions.
Syntax:
show functions
e.g.
Splines as User Defined Functions.
and
Use of functions and complex variables for airfoils
grid
The optional set grid draws a grid at the major tic marks with the axis
linetype. The grid can include the minor tic marks by set grid mxtics
and/or set grid mytics. The default is no grid on the minor tic marks.
Syntax:
set grid {mxtics OR mytics}
set nogrid
show grid
hidden3d
The set hidden3d command enables hidden line removal for explicit
surface plotting (see splot).
Hidden line removal may be used for both explicit functions and for
explicit data. It now works for parametric surfaces as well.
When this flag is set both the surface hidden portion and possibly
its hidden contours (see set contour) as well as the hidden grid will be
removed. Labels and arrows are always visible and are unaffected by this
command.
Each surface has its hidden parts removed with respect to itself and to
other surfaces, if more than one surface is plotted. This mode is
meaningful when surfaces are plotted using line style drawing only.
Syntax:
set hidden3d
set nohidden3d
show hidden3d
e.g.
Hidden Line Removal Demo and
Complex Hidden Line Demo.
isosamples
An isoline is a curve parametrized by one of the surface parameters
while the other surface parameter is fixed. Isolines are a simple
means to display a surface. By fixing the u parameter of surface
s(u,v), the iso-u lines of the form c(v) = s(u0,v) are produced, and
by fixing the v parameter, the iso-v lines of the form c(u) = s(u,v0)
are produced.
The isoline density of surfaces may be changed by the set isosamples
command. By default, sampling is set to 10 isolines per u or v axis.
A higher sampling rate will produce more accurate plots, but will take
longer. This parameter has no effect on data file plotting.
Syntax:
set isosamples <iso_1> {,<iso_2>}
show isosamples
Each surface plot will have <iso_1> iso-u lines and <iso_2> iso-v lines.
If you only specify <iso_1>, <iso_2> will be set to the same value as
<iso_1>.
When a surface plot is being done without the removal of hidden
lines, set samples also has an effect on the number of points being
evaluated. See set samples.
key
The set key enables a key describing curves on a plot. By default
the key is placed in the upper right corner of the plot. The keywords
left, right, top, bottom, outside and below is provided to
place the keys in the other corners inside the plot or to the right
(outside) or below the plot. They may be given alone or combined.
Justification of the key label is controled by Left or Right. The
default is Right.
Syntax:
set key
set key <x>,<y>{,<z>}
set key <keyword> {<keyword> {<justification>}}
set nokey
show key
The coordinates <x>, <y> (and <z> for splots) specify the location
of the key on the plot. The key is drawn as a sequence of lines, with
one plot described on each line. On the right hand side of each line
is a representation that attempts to mimic the way the curve is
plotted. On the left side of each line is the text description,
obtained from the plot command. See plot title to change this
description. The lines are vertically arranged so an imaginary
straight line divides the left- and right-hand sides of the key. It is
the coordinates of this line that are specified with the set key
command. In a plot, only the x and y coordinates are used to specify
the line position. For a splot, x, y and z are all being used as a
3-d location mapped using the same mapping as the plot itself to form
the required 2-d screen position of the imaginary line.
Some or all of the key may be outside of the plot boundary, although
this may interfere with other labels and may cause an error on some
devices. If you use the keywords outside or below, gnuplot makes
space for the keys and the plot becomes smaller. Putting keys outside
to the right, they occupy as few colums as possible, and putting them
below, as many culumns as possible (depending of the length of the
labels). Thus stealing as little space from the plot as possible.
Examples:
This places the key at the default location:
set key
This disables the key:
set nokey
This places a key at coordinates 2,3.5,2
set key 2,3.5,2
Put the keys below the plot
set key below
Place the beys in the bottom left corner and justify the text left:
set key left bottom Left
Put it in the default corner:
set key
keytitle
This command allows a key header to the printed above the keys.
Syntax:
set keytitle "<string>"
label
Arbitrary labels can be placed on the plot using the set label
command. If the z coordinate is given on a plot it is ignored; if
it is missing on a splot it is assumed to be 0. The strings is scanned
for backslash-octal (\nnn) conversion.
Syntax:
set label {<tag>} {"<label_text>"} {at <x>,<y>{,<z>}}
{<justification>}
set nolabel {<tag>}
show label
The text defaults to "", and the position to 0,0,0. The <x>, <y>, and
<z> values are in the graph's coordinate system. The tag is an
integer that is used to identify the label. If no <tag> is given, the
lowest unused tag value is assigned automatically. The tag can be used
to delete or change a specific label. To change any attribute of an
existing label, use the set label command with the appropriate tag,
and specify the parts of the label to be changed.
By default, the text is placed flush left against the point x,y,z.
To adjust the way the label is positioned with respect to the point
x,y,z, add the parameter <justification>, which may be left, right
or center, indicating that the point is to be at the left, right or
center of the text. Labels outside the plotted boundaries are
permitted but may interfere with axes labels or other text.
If one (or more) axis is timeseries, the coordiate should be given as
a quoted time string according to the timefmt-format string. See
set {x,y,z}data and set timefmt.
Examples:
To set a label at (1,2) to "y=x" use:
set label "y=x" at 1,2
To set a label "y=x^2" with the right of the text at (2,3,4), and tag
the label number 3, use:
set label 3 "y=x^2" at 2,3,4 right
To change the preceding label to center justification, use:
set label 3 center
To delete label number 2 use:
set nolabel 2
To delete all labels use:
set nolabel
To show all labels (in tag order) use:
show label
Timeseries (timefmt="%d/%m/%y,%H:%M):
set label "Harvest" at "25/8/93",1
(The EEPIC, Imagen, LaTeX, and TPIC drivers allow \\ in a string to specify
a newline.)
logscale
Log scaling may be set on the x, y, and z axes.
Syntax:
set logscale <axes> <base>
set nologscale <axes>
show logscale
where <axes> may be any combinations of x, y, and z, in any
order, and where <base> is the base of the log scaling. If <base>
is not given, then 10 is assumed. If <axes> is not given then all
three axes are assumed. The command set logscale turns on log
scaling on the specified axes, while set nologscale turns off
log scaling.
Examples:
To enable log scaling in both x and z axes:
set logscale xz
To enable scaling log base 2 of the y axis:
set logscale y 2
To disable z axis log scaling:
set nologscale z
mapping
Syntax:
set mapping { cartesian | spherical | cylindrical }
Data for splots are usually in regular Euclidean space and are
provided in Cartesian coordinates. Such 3-d data require three
coordinates (x, y and z) or one coordinate (only z) in each line in
the data file. In order to be able to use spherical or cylindrical
coordinate systems, use the set mapping command. In both cases two
coordinates are expected in each line of the data. For a spherical
coordinate system, these are theta and phi (in units as specified by
set angles) and the mapping is:
x = cos( theta ) * cos( phi )
y = sin( theta ) * cos( phi )
z = sin( phi )
For a cylindrical coordinate system, the mapping uses two variables,
theta (in units as specified by set angles) and z:
x = cos( theta )
y = sin( theta )
z = z
Again, note that mapping will affect data file splots only.
Mapping Demos.
offsets
The amount of the graph that the plot takes up may be controlled to
some extent with the set offsets command. This command takes four
offset arguments: <left>, <right>, <top> and <bottom>. By default,
each offset is 0. Each offset may be a constant or an expression. Left
and right offsets are given in units of the x axis, while top and
bottom offsets are given in units of the y axis. The plot of sin(x),
displayed with offsets of 0, 0, 2, 2 will take up 1/3 of the
displayed y axis. Offsets are particularly useful with polar
coordinates as a means of compensating for aspect ratio distortion.
Offsets are ignored in splots.
Syntax:
set offsets <left>, <right>, <top>, <bottom>
show offsets
output
By default, plots are displayed to the standard output. The
set output command redirects the display to the specified file
or device.
Syntax:
set output {"<filename>"}
show output
The filename must be enclosed in quotes. If the filename is
omitted, output will be sent to the standard output.
On machines with popen functions (UNIX), output can be piped
through a shell command if the first letter of the filename
is '|'. For instance,
Syntax:
set output "|lpr -Plaser filename"
set output "|lp -dlaser filename"
(On MSDOS machines, set output "prn" will direct the output
to the default printer.)
parametric
The set parametric command changes the meaning of plot (splot)
from normal functions to parametric functions. The command
set noparametric changes the plotting style back to normal,
single-valued expression plotting.
In 2-d plotting, a parametric function is determined by a pair
of parametric functions operating on a parameter. An example
of a 2-d parametric function would be plot sin(t),cos(t) (which
defines a circle).
For 3-d plotting, the surface is described as x=f(u,v), y=g(u,v),
z=h(u,v). Therefore a triplet of functions are required. An example of
3-d parametric function would be cos(u)*cos(v),cos(u)*sin(v),sin(u)
(which defines a sphere). It takes three parametric function
specifications in terms of the parametric dummy arguments to describe
a single graph.
The total set of possible plots is a superset of the simple f(x)
style plots, since the two (three) functions can describe the
x and y (and z) values to be computed separately. In fact,
plots of the type t,f(t) (u,v,f(u,v)) are equivalent to those
produced with f(x) when the x values are computed using the
identity function as the first function.
Note that the order the parametric functions are specified is
xfunction, yfunction (and zfunction) and that each operates over the
common parametric domain.
Also, the set parametric function implies a new range of values.
Whereas the normal f(x) and f(x,y) style plotting assume an xrange
and yrange (and zrange), the parametric mode additionally specifies a
trange, urange, and vrange. These ranges may be set
directly with set trange, set urange and set vrange, or by
specifying the range on the plot or splot commands. Currently
the default range for these parametric variables is [-5:5].
Setting the ranges to something more meaningful is expected.
pointsize
The set pointsize command changes the size of the points used in plots.
Default is pointsize 1.0. Larger pointsizes (>1.0) are usefull for high
resolution in bitmapped graphics.
Please note that the pointsize setting is not supported with all terminal
types.
polar
The set polar command changes the meaning of the plot from
rectangular coordinates to polar coordinates. In polar coordinates,
the dummy variable (x) is an angle. The range of this angle is changed
from whatever it was to [0:2*pi], or, if degree unit has been selected,
to [0:360] (see set angles).
The command set nopolar changes the meaning of the plot back to the
default rectangular coordinate system. The range of x is changed from
whatever it was to [-10:10].
The set polar command is not supported for splots. See the
set mapping command for similar functionality for splots.
While in polar coordinates the meaning of an expression in x is really
r = f(x), where x is an angle of rotation. The xrange controls the
domain (the angle) of the function, and the yrange controls the range
(the radius). The plot is plotted in a rectangular box, and the x and
y axes are both in units of the radius. Thus, the yrange controls both
dimensions of the plot output. The tics and units are written along
the axes rather than at the left and bottom. These unit are offset by
<rmin> specified by the rrange (See set rrange). It is not
possible to specify different output dimensions in the x or y
directions. The yrange can be used to shift the plot diagonally to
display only the first or third quadrants.
Syntax:
set polar
set nopolar
show polar
Example:
set polar
plot x*sin(x)
plot [-2*pi:2*pi] [-3:3] x*sin(x)
The first plot uses the default polar angular domain of 0 to 2*pi.
The radius (and the size of the plot) is scaled automatically. The
second plot expands the domain, and restricts the range of the radius
(and the size of the plot) to [-3:3].
Polar demos
Polar Data Plot.
rrange
The set rrange command sets the radial range used to compute x and y
values when in polar mode. If not in polar mode (see set polar) then
this range is not used. Use of this command offsets the polar
singularity to the <rmin> value and shifts the units on the axes tic
marks. For instance, set rrange [-40:40] would set the origin to -40
and would plot values of radial values between -40 to 40. Thus, if
360 degrees of data were plotted, then the plot would extend 80 units
in radially from the origin. To view the entire plot, a
set yrange [-80:80] command would create a square viewport with
a circular plot tangent at the axes. Because xrange is used
specify the angular extent, only a square viewport can be specified
by yrange. For instance, set yrange [0:80] would display the
first quadrant and set yrange [-80:0] would display the third
quadrant. Any square viewport of any size can be specified but it
is constrained to be centered on a 45 degree line.
This range may also be specified on the plot command line when in
polar mode.
Syntax:
set rrange [{<rmin> : <rmax>}]
where <rmin> and <rmax> terms are constants or expressions.
Both the <rmin> and <rmax> terms are optional. Anything omitted will
not be changed, so
set rrange [:10]
changes rmax to 10 without affecting rmin.
samples
The sampling rate of functions may be changed by the set samples
command. By default, sampling is set to 100 points. A higher sampling
rate will produce more accurate plots, but will take longer. This
parameter no longer has any effect on data-file plotting.
Syntax:
set samples <samples_1> {,<samples_2>}
show samples
When a 2-d plot is being done, only the value of <samples_1> is
relevant.
When a surface plot is being done without the removal of hidden
lines, the value of samples specifies the number of samples that are
evaluated per iso line. Each iso-v line will have <sample_1> samples
and each iso-u line will have <sample_2> samples. If you only specify
<samples_1>, <samples_2> will be set to the same value as <samples_1>.
See also set isosamples.
size
The set size command scales the displayed size of the plot. On some
terminals, changing the size of the plot will result in text being
misplaced. Increasing the size of the plot may produce strange
results. Decreasing is safer.
Syntax:
set size {<xscale>,<yscale>}
show size
The <xscale> and <yscale> values are the scaling factors for the size.
The defaults (1,1) are selected if the scaling factors are omitted.
Examples:
To set the size to normal size use:
set size
To make the plot half size use:
set size 0.5,0.5
To make a landscape plot have a 1:1 aspect ratio in polar mode use:
set size 0.721,1.0
To show the size use:
show size
For the LaTeX and Fig terminals the default size (scale factor 1,1)
is 5 inches wide by 3 inches high. The big Fig terminal (bfig) is 7
inches wide by 5 inches high. The postscript default is landscape mode
10 inches wide and 7 inches high.
Note that the size of the plot includes the space used by the labels;
the plotting area itself is smaller.
style
Plots may be displayed in one of thirteen styles: lines, points,
linespoints, impulses, dots, steps, fsteps, {x,y,xy}errorbars,
boxes, boxerrorbars, or boxxyerrorbars.
The lines style connects adjacent points with lines.
The points style displays a small symbol at each point.
The linespoints style does both lines and points.
The impulses style displays a vertical line from the x axis
(or from the grid base for splot) to each point. The dots style
plots a tiny dot at each point; this is useful for
scatter plots with many points.
The errorbars (or yerrorbars), xerrorbars, xyerrorbars styles are only
relevant to 2-d data file plotting. It
is treated like points for splots and function plots. For data
plots, errorbars is like points, except that a vertical or
horizontal error bar is also drawn: for each point (x,y), a line is
drawn from (x,ylow) to (x,yhigh) or (xlow,y) to (xhigh,y). A tic mark is
placed at the ends of the error bar. The (ylow, yhigh) or (xlow,xhigh)
values are read from the data file's columns, as specified with the using
option to plot. See plot errorbars for more information.
The boxes style is only relevant to 2-d plotting. It draws
a box centred about the given x coordinate from the yaxis to the given
y coordinate. The width of the box is obtained in one of three
ways. If a data file has a third column, this will be used to set
the width of the box. Otherwise, if a width has been set using the
set boxwidth command, this will be used. Otherwise the width of each
box will be calculated automatically so that it touches the adjacent
boxes. Another style called boxerrorbars is also available and is
only relevant to 2-d data file plotting. This style is a combination
of the boxes and errorbars styles. The boxwidth will come from the fourth
column if the y errors are in the form of "ydelta" and the boxwidth was not
previously set equal to -2.0 (set boxwidth -2.0) or from the fifth
column if the y errors are in the form of "ylow yhigh". The boxwidth = -2.0 is
for the special case of 4-column data and the y errors are in the form of
"ylow yhigh". The boxwidth will be calculated automatically so that each box
touches the adjacent boxes. The width will also be automatically calculated
if 3-column data is used. The boxxyerrorbars
style is like the xyerrorbars option except that a box with width
(xhigh-xlow) and height (yhigh-ylow) is drawn instead of a cross of that size.
For 2-d data with more than two columns, gnuplot will be picky about the
allowed plot styles. For three columns only xerrorbars, boxes,
errorbars (or yerrorbars), and boxerrorbars are allowed. If another plot
style is used,
the style will be changed to yerrorbars. The boxerrorbars style will
calculate the boxwidth automatically. For four columns only xerrorbars,
xyerrorbars, boxxyerrorbars, boxerrorbars, and errorbars (or
yerrorbars) are allowed. An illegal plot style will be changed to
yerrorbars. Five column data allows only the boxerrorbars style. An
illegal style will be changed to boxerrorbars before plotting. Six and
seven column data only allows the xyerrorbars and boxxyerrorbars styles.
Illegal styles will be changed to xyerrorbars before plotting. Use the
using option for plot to setup the correct number of columns for the
style you want.
The steps and fsteps styles is only relevant to 2-d plotting. The
steps style connects consecutive points with two line segments: the first
from (x1,y1) to (x2,y1) and the second from (x2,y1) to (x2,y2).
The fsteps: (x1,y1) to (x1,y2) and (x1,y2) to (x2,y2).
Default styles are chosen with the set function style and
set data style commands. See plot style for information about
how to override the default plotting style for individual functions.
Syntax:
set function style <style>
set data style <style>
show function style
show data style
where <style> is lines, points, linespoints, impulses,
dots, steps, fsteps, {x,y,xy}errorbars, boxes, boxerrorbars,
or boxxyerrorbars.
surface
set surface controls the display of surfaces. It is useful if
contours are to be displayed by themselves. Whenever set nosurface
is issued, no surface isolines/mesh will be drawn. See also
set contour.
Syntax:
set surface
set nosurface
show surface
terminal
GNUPLOT supports many different graphics devices. Use the
set terminal command to select the type of device for which
GNUPLOT will produce output.
Syntax:
set terminal {<terminal-type>}
show terminal
If <terminal-type> is omitted, GNUPLOT will list the available
terminal types. <terminal-type> may be abbreviated.
Use set output to redirect this output to a file or device.
Several terminals have additional options. For example, see dumb,
iris4d, hpljii or postscript.
aifm
atari ST
dumb
epson
gpic
hpljii
latex
imagen
linux
iris4d
mf
mif
nec-cp6
pbm
pcl5
postscript
enhanced postscript
pslatex
fig
regis
table
uniplex
windows
aifm
Several options may be set in the Adobe Illustrator 3.0 driver.
Syntax:
set terminal aifm {<color>}
{"<fontname>"} {<fontsize>}
Selecting default sets all options to their default values.
<color> is either color or monochrome.
"<fontname>" is the name of a valid PostScript font.
<fontsize> is the size of the font in PostScript points, before
scaling by the set size command.
Defaults are monochrome, "Helvetica", and 14pt.
Also, since AI does not really support multiple pages, multiple
graphs will be output directly on one another. However, each graph
will be grouped individually, making it easy to separate them inside
AI (just pick them up and move them).
Examples:
set term aifm
set term aifm 22
set size 0.7,1.4
set term aifm color "Times-Roman" 14
atari ST
The atari terminal has an option to set the character size and the
screen colors. The driver expects a space separated list the char size
and maximal 16 3 digit hex numbers where each digit represents RED, GREEN
and BLUE (in that order). The range of 0-15 is scaled to whatever color
range the screen actually has. On a normal ST screen, odd and even
intensities are the same.
Examples:
set terminal atari 4 # (use small (6x6) font)
set terminal atari 6 0 # (set monochrome screen to white on black)
set terminal atari 13 0 fff f00 f0 f ff f0f ff0
# (set first eight colors to black, white, green, blue, cyan, \
purple, and yellow and use large font (8x16).)
Additionally, if an environment variable GNUCOLORS exists, its
contents are interpreted as an options string, but an explicit terminal
option takes precedence.
dumb
The dumb terminal driver has an optional size specification.
Syntax:
set terminal dumb {<xsize> <ysize>}
where <xsize> and <ysize> set the size of the dumb terminals. Default
is 79 by 24.
Examples:
set term dumb
set term dumb 79 49 # VGA screen--why would anyone want to do that?
epson
This set of drivers support Epson printers and derivatives. See also
the NEC driver. epson is a generic 9 wire printer with a resolution
of 512x384. starc is a Star Color printer with the same resolution.
epson180 and epson60 are 180 dpi and 60 dpi drivers for newer
24 wire printers. This also includes bubble jet printers. Their
resolutions are 1260x1080 and 480x360, respectively. The tandy60
is identical to the epson60 driver with one additional escape
sequence to start IBM mode. With all of these drivers, a binary
copy is required on a PC to print. Do not use print.
copy file /b lpt1:
gpic
This driver is only known to work the Free Software Foundation
gpic/groff package. Modification for the Document Workbench
pic/troff package would be appreciated. FSF gpic can also
produce TeX output.
A simple graph can be formatted using
groff -p -mpic -Tps file.pic > file.ps.
The output from pic can be pipe-lined into eqn, so it is possible to put
complex functions in a graph with the set label and set {x/y}label commands.
For instance,
set ylab '@space 0 int from 0 to x alpha ( t ) roman d t@'
Will label the y-axis with a nice integral if formatted with the
command:
gpic filename.pic | geqn -d@@ -Tps | groff -m[macro-package] -Tps
> filename.ps
Figures made this way can be scaled to fit into a document. The pic
language is easy to understand, so the graphs can be edited by hand if
need be. All coordinates in the pic-file produced by gnuplot are given
as x+gnuplotx and y+gnuploty. By default x and y are given the value 0
If this line is removed with an editor in a number of files one can
put several graphs i one figure like this (default size is 5.0x3.0 inches)
.PS 8.0
x=0;y=3
copy "figa.pic"
x=5;y=3
copy "figb.pic"
x=0;y=0
copy "figc.pic"
x=5;y=0
copy "figd.pic"
.PE
This will produce an 8 inches wide figure with four graphs in two rows
on top of each other
One can also achieve the same thing by the command
set term pic x y
For example, using
.PS 6.0
copy "trig.pic"
.PE
hpljii
The HP LaserJet II and HP DeskJet drivers have a single option.
Syntax:
set terminal hpljii {<resolution>}
set terminal hpdj {<resolution>}
where <resolution> is the resolution of the output in dots per inch.
It must be 75, 100, 150 or 300. Note: there must be
enough memory available to rasterize at the higher resolutions.
Example:
set terminal hpljii 150
latex
The LaTeX and EMTeX driver allows one to specify a font type and a font
size for the labels around a gnuplot graph.
Options are:
Fonts:
default (Roman 10 point)
courier
roman
at any size you specify. (BEWARE METAFONT will not like odd sizes.)
eg.
gnuplot> set term latex courier 5
Unless your driver is capable of building fonts at any size (e.g. dvips),
stick to the standard 10, 11 and 12 point size.
imagen
The imagen driver is able to draw several plots on each page (in either
portrait or landscape orientation), and fontsize may
also be specified.
Options are:
portrait
landscape (default)
[ x , y ] (where x and y is number of plots in x- and y direction
on the page)
n (where n is fontsize in points)
To plot 6 plots pr page in two columns in portrait orientation:
set term imagen po [2,3]
linux
The Linux driver has only a few options. You can select SVGA or a VGA
screen and force chipsets if the svgalib fails to detect your chipset.
Both arguments are optional. If no chipset is specifed, it is
autodetected (this option should really only be used if it is
autodetected incorrectly). The mode defaults to SVGA; if it is not
available, it automatically drops to VGA.
Syntax:
set terminal linux {chipset} {mode}
Mode can be:
VGA - force 640x480x16 (useful for Tridents)
SVGA - use 1024x768x256 (if available)
S800 - use 800x600x256 (if available)
S816 - use 800x600x16 (512k users, not available)
Currently the following chipsets can be used with svgalib (v0.5):
TVGA8900
ET4000
CIRRUS
OAK (?)
Other chipsets are supported to 640x480x16 as generic VGA.
The current svgalib (0.5) doesn't handle Trident cards very well, if
your screen is not restored properly, you will have to use the VGA
option.
iris4d
The iris4d driver can operate in two modes.
Syntax:
set terminal iris4d {24}
If the hardware supports only 8 bits, use the default
set terminal iris4d. If, however, the hardware supports 24 bits
(8 per red/green/blue), use set terminal iris4d 24.
When using 24-bit mode, the colors can be directly specified via the
file .gnuplot_iris4d that is searched in the current directory and
then in the home directory specified by the HOME environment variable.
This file holds RGB values for the background, border, labels and nine
plotting colors, in that order. For example, here is a file containing
the default colors:
85 85 85 /* Back Ground */
0 0 0 /* Boundary */
170 0 170 /* Labeling */
85 255 255 /* Plot Color 1 */
170 0 0 /* Plot Color 2 */
0 170 0 /* Plot Color 3 */
255 85 255 /* Plot Color 4 */
255 255 85 /* Plot Color 5 */
255 85 85 /* Plot Color 6 */
85 255 85 /* Plot Color 7 */
0 170 170 /* Plot Color 8 */
170 170 0 /* Plot Color 9 */
This file has exactly 12 lines of RGB triples. No empty lines are
allowed and anything after the third number in line is ignored.
mf
The mf terminal driver creates a input file to the MetaFont program.
Thus a figure may be used in the TeX document in the same way as a
character is.
To use the plot in a document the MetaFont program must be run
with the output file from GnuPlot as input. Thus, the user needs a basic
knowledge of the font creating process and inclusion of a new font in a
document. However, if the Metafont program is set up properly at the
local site an unexperienced user could perform the operation without
much trouble.
The text support is based on a MetaFont character set.
Currently the Computer Modern Roman font set is input but the
user are in principal free to chose whatever fonts he/she needs.
The MetaFont source files for the chosen font must be available.
Each character is stored in a separate picture variable in MetaFont. These
variables may be manipulated (rotated, scaled etc.) when characters are
needed. The drawback is the interpretation time in the MetaFont
program. On some machines (i.e. PC) the limited amount of memory available
may also cause problem if too many pictures are stored.
Metafont Instructions
- Set your terminal to metafont:
set terminal mf
- Select an output-file, e.g.:
set output "myfigures.mf"
- Do your plots. Each plot will generate a separate character. Its default
size will be 5*3 inches. You can change the size by saying set size 0.5,0.5
or whatever fraction of the default size you want to have.
- Quit gnuplot.
- Generate a tfm- and gf-file by running metafont on the output of gnuplot.
Since the plot is quite large (5*3 in), you will have to use a version
of metafont that has a value of at least 150000 for memmax. On Unix-systems
these are conventionally installed under the name bigmf. For the following
assume that the command virmf stands for a big version of metafont. For example:
- Invoke metafont:
virmf '&plain'
- Select the output device: At the metafont prompt ('*') type:
\mode:=CanonCX; % or whatever printer you use
- Optionally select a magnification:
mag:=1; % or whatever you wish
- Input the gnuplot-file:
input myfigures.mf
On a typical Unix machine there will usually be a script called mf that
executes virmf '&plain', so you probably can substitute mf for virmf &plain.
This will generate two files: mfput.tfm and mfput.$$$gf (where $$$ indicates
the resolution of your device). The above can be conveniently achieved by
typing everything on the command line, e.g.:
virmf '&plain' '\mode:=CanonCX; mag:=1; input myfigures.mf'
In this case the output files will be named myfigures.tfm and
myfigures.300gf.
- Generate a pk-file from the gf-file using gftopk:
gftopk myfigures.300gf myfigures.300pk
The name of the output-file for gftopk depends on the dvi-driver you use.
Ask your local TeX-administrator about the naming conventions.
Next, either install the tfm- and pk-files in the appropriate directories,
or set your environment-variables properly. Usually this involves setting
TEXFONTS to include the current directory and do the same thing for the
environment-variable that your dvi-driver uses (no standard name here...).
This step is necessary so that TeX will find the font-metric file and your
dvi-driver will find the pk-file.
- To include your plots in your document you have to tell TeX the font:
\font\gnufigs=myfigures
Each plot you made is stored in a single character. The first plot is
character 0, the second is character 1, and so on... After doing the above
step you can use the plots just like any other characters. Therefore, to
place plots 1 and 2 centered in your document, all you have to do is:
\centerline{\gnufigs\char0}
\centerline{\gnufigs\char1}
in plain TeX. For LaTeX you can, of course, use the picture environment
and place the plot according to your wishes using the \makebox and \put
macros.
It saves you a lot of time, once you have generated the
font, since TeX handles the plots as characters and uses minimal time to
place them. Also the documents you make change more often, than the plots
do. Also it saves a lot of TeX-memory. One last advantage of
using the metafont-driver is that the dvi-file really remains device
independent, because no \special-commands are used as in the eepic- and
tpic-drivers.
mif
Several options may be set in the MIF 3.00 driver.
Syntax:
set terminal mif {<pentype>} {<curvetype>} {<help>}
<pentype> selects "colour" of the graphics.
colour plot lines with line types >= 0 in colour (MIF sep. 2-7).
monochrome plot all line types in black (MIF sep. 0).
<curvetype> selects how "curves" are plotted.
polyline plot curves as continuous curves.
vectors plot curves as collections of vectors
<help> print online help on standard error output.
help print a short description of the usage, and the options
? print a short description of the usage
This terminal driver produces Frame Maker MIF format version 3.00. It
plots in MIF Frames with the size 15*10 [cm], and plot primitives with
the same pen will be grouped in the same MIF group. Plot primitives in
a gnuplot plot will be plotted in a MIF Frame, and several MIF Frames
are collected in one large MIF Frame.
Plot primitives with line types >= 0 will as default be drawn in colour.
As default curves are plotted as continuous lines. The MIF font used for
text is "Times".
Examples:
set term mif
set term mif vectors
set term mif help
nec-cp6
One option may be set in the nec-cp6 driver. The resolution of this
driver is 400x320.
Syntax:
set terminal nec-cp6 monochrome
set terminal nec-cp6 color
set terminal nec-cp6 draft
pbm
Several options may be set in the PBMplus driver.
Syntax:
set terminal pbm {<fontsize>} {<colormode>}
where <fontsize> is small, medium, or large and <colormode> is
monochrome, gray or color.
Default size is 640 pixels wide and 480 pixels high.
The output for monochrome is a portable bitmap (one bit per pixel).
The output for gray is a portable graymap (three bits per pixel).
The output for color is a portable pixmap (color, four bits per pixel).
The output of these drivers can be used with Jef Poskanzer's
excellent PBMPLUS package which provides programs to convert
the above PBMPLUS formats to GIF, TIFF, MacPaint, Macintosh PICT,
PCX, X11 bitmap and many others.
Examples:
set term pbm small
set size 2,2
set term pbm color medium
pcl5
Three options may be set in the pcl5 driver. The driver
actually uses HPGL-2 but there is a name conflict among
the terminal devices.
Syntax:
set terminal pcl5 {<mode>} {<font>} {<fontsize>}
where <mode> is landscape, or portrait, <font> is stick,
univers, or cg_times, and fontsize is the size in points.
set terminal pcl5 landscape
postscript
Several options may be set in the PostScript driver.
Syntax:
set terminal postscript {<mode>} {<color>} {<dashed>}
{"<fontname>"} {<fontsize>}
where <mode> is landscape, portrait, eps or default.
Selecting default sets all options to their defaults.
<color> is either color or monochrome.
<dashed> is either solid or dashed.
"<fontname>" is the name of a valid PostScript font.
<fontsize> is the size of the font in PostScript points.
Defaults are landscape, monochrome, dashed, "Helvetica", and 14pt.
Default size of PostScript plot is landscape mode 10 inches wide
and 7 inches high.
To get EPS output, use the eps mode and make only one plot per file.
In eps mode the whole plot is halved in size; the fonts are half the
given size, and the plot is 5 inches wide and 3.5 inches high.
Examples:
set term postscript default # old postscript
set term postscript landscape 22 # old psbig
set term postscript eps 14 # old epsf1
set term postscript eps 22 # old epsf2
set size 0.7,1.4
set term post portrait color "Times-Roman" 14
enhanced postscript
The "Enhanced PostScript" driver has extended capabilities
beyond the regular PostScript driver. Several options may be
set in the Enhanced PostScript driver.
Syntax:
set terminal enhpost {<mode>} {<color>} {<dashed>}
{<duplexing>} {"<fontname>"} {<fontsize>}
where <mode> is landscape, portrait, eps or default.
Selecting default sets all options to their defaults.
<color> is either color or monochrome.
<dashed> is either solid or dashed.
<duplexing> is either simplex or duplex (don't set this if your printer can't do it).
"<fontname>" is the name of a valid PostScript font.
<fontsize> is the size of the font in PostScript points.
Defaults are landscape, monochrome, dashed, 'printer-default-plex',
"Helvetica", and 14pt.
Default size of Enhanced PostScript plot is landscape mode 10 inches wide
and 7 inches high.
To get EPS output, use the eps mode and make only one plot per file.
In eps mode the whole plot is halved in size; the fonts are half the
given size, and the plot is 5 inches wide and 3.5 inches high.
Examples:
set term enhpost landscape 22
set term enhpost eps 14
set term enhpost landscape simplex
set size 0.7,1.4
set term enhpost portrait color "Times-Roman" 14
This "enhanced" driver allows any text to contain the following special
formatting instructions (e.g., use the SET FORMAT command to put them in
for axis scales):
Control Examples Explanation
^ a^x superscript
_ a_x subscript
@ @x or a@^b_c phantom box (occupies no width)
{text} can be used to allow multiple-character text, where only a single
character is expected (e.g., 2^{10}). To change the font and/or size, use
the full form: {/[fontname][=fontsize] text} (For example,
{/Symbol=20 G} is a 20 point GAMMA). (The '/' character MUST be the first
character after the '{'.)
The phantom box is useful for a@^b_c to align superscript and subscript,
and for overwriting an accent on a letter.
It is common sense to put the shorter of the two in the phantom box.
You can access special symbols numerically by specifying
\character-code (in octal), e.g., {/Symbol \245} is infinity.
You can escape control characters using \, e.g., \\, \{, \}, \^, \@
pslatex
There are a few options for the pslatex driver.
Syntax:
set terminal pslatex {<color>} {<rotate>} {auxfile}
<color> is either color or monochrome. if default is specified,
the plot will have rotated text and be in monochrome, all in one file.
<rotate> is either rotate or norotate and determines if the vertical
axis label is rotated.
If auxfile is specified, directs the driver to put the postscript
commands into an auxiliary file instead of directly into the latex file.
This is useful if your plots are large, and dvips cannot handle the
picture. The postscript file name for this option is determined by
replacing the trailing .tex with .ps in the output file name.
Example:
set term pslatex auxfile # put postscript parts in file foo.ps
set output "foo.tex"
fig
The fig terminal device have the option of either color or monochrome
and small or large image. The default is monochrome and small.
To select color, use:
set terminal fig color
To select large, use:
set terminal fig large
The large option is a substitute for the bfig terminal in earlier version,
which is no longer supported.
regis
The regis terminal device has the option of using 4 or 16
colors. The default is 4. For example:
set term regis 16
table
Instead of producing a picture, term type table prints out
the evaluation results in a multicolumn ASCII table of X Y Z values.
For those times when you really want to see the numbers, now you
can see them on the screen or save to a file.
uniplex
The uniplex driver is able to combine several plots in one image.
The option portrait causes the image to be drawn in a window where the
width is about 2/3 of the hight (default is landscape: The image hight is
ca 2/3 of the width). Fontsize may also be spesified (sizes 1-8). Only one
image is allowed pr file. If a 'X' is include in the set output filename,
the 'X' is substituted with a seqentional plot number.
Options are:
portrait
landscape (default)
[ x , y ] (where x and y is number of plots in x- and y direction
of the image)
n (where n is fontsize (1-8))
To plot 6 plots in one image in two columns in portrait orientation:
set term uniplex po [2,3]
windows
Three options may be set in the windows driver.
Syntax:
set terminal windows {<color>} {"<fontname>"} {<fontsize>}
<color> is either color or monochrome.
"<fontname>" is the name of a valid Windows font.
<fontsize> is the size of the font in points.
graph-menu
printing
text-menu
wgnuplot.ini
windows3.0
graph-menu
The gnuplot graph window has the following options on a pop up menu
accessed by pressing the right mouse button or selecting Options
from the system menu:
Bring to Top when checked brings the graph window to
the top after every plot.
Color when checked enables color linestyles.
When unchecked it forces monochrome linestyles.
Copy to Clipboard copies a bitmap and a Metafile picture.
Background... sets the window background color.
Choose Font... selects the font used in the graphics window.
Line Styles... allows customization of the line colors
and styles.
Print... prints the graphics windows using a Windows printer
driver and allows selection of the printer and scaling of the output.
The output produced by Print is not as good as that from gnuplot's
own printer drivers.
Update wgnuplot.ini saves the current window locations, window
sizes, text window font, text window font size, graph window font,
graph window font size, background color and linestyles to the
initialisation file WGNUPLOT.INI.
printing
In order of preference, graphs may be be printed in the
following ways.
1. Use the gnuplot command set terminal to select a printer
and set output to redirect output to a file.
2. Select the Print... command from the gnuplot graph window.
An extra command screendump does this from the text window.
3. If set output "PRN" is used, output will go to a temporary file.
When you exit from gnuplot or when you change the output with another
set output command, a dialog box will appear for you to select
a printer port. If you choose OK, the output will be printed
on the selected port, passing unmodified through the print
manager. It is possible to accidently (or deliberately) send
printer output meant for one printer to an incompatible printer.
text-menu
The gnuplot text window has the following options on a pop up menu
accessed by pressing the right mouse button or selecting Options
from the system menu:
Copy to Clipboard copies marked text to the clipboard.
Paste copies text from the clipboard as if typed by the user.
Choose Font... selects the font used in the text window.
System Colors when selected makes the text window honor the
System Colors set using the Control Panel. When unselected,
text is black or blue on a white background.
Update wgnuplot.ini saves the current text window location, text
window size, text window font and text window font size to the
initialisation file WGNUPLOT.INI.
MENU BAR
If the menu file WGNUPLOT.MNU is found in the same directory as
WGNUPLOT.EXE, then the menu specified in WGNUPLOT.MNU will
be loaded.
Menu commands are:
[Menu] Start a new menu with the name on the following line
[EndMenu] End current menu.
-- Insert a horizontal menu separator
| Insert a vertical menu separator
[Button] Put next macro on a push button instead of a menu.
Macros take two lines with the macro name (menu entry) on the first
line and the macro on the second line. Leading spaces are ignored.
Macros commands are:
[INPUT] Input string with prompt terminated by [EOS] or {ENTER}
[EOS] End Of String terminator. Generates no output.
[OPEN] Get name of file to open from list box, with title of
list box terminated by [EOS], followed by default
filename terminated by [EOS] or {ENTER}
This uses COMMDLG.DLL from Windows 3.1.
[SAVE] Get name of file to save. Similar to [OPEN]
Macros character substitutions are:
{ENTER} Carriage Return '\r'
{TAB} Tab '\011'
{ESC} Escape '\033'
{^A} '\001'
...
{^_} '\031'
Macros are limited to 256 characters after expansion.
wgnuplot.ini
Windows gnuplot will read some of its options from the [WGNUPLOT] section
of WGNUPLOT.INI in the Windows directory.
An example WGNUPLOT.INI file is shown below.
[WGNUPLOT]
TextOrigin=0 0
TextSize=640 150
TextFont=Terminal,9
GraphOrigin=0 150
GraphSize=640 330
GraphFont=Arial,10
GraphColor=1
GraphToTop=1
GraphBackground=255 255 255
Border=0 0 0 0 0
Axis=192 192 192 2 2
Line1=0 0 255 0 0
Line2=0 255 0 0 1
Line3=255 0 0 0 2
Line4=255 0 255 0 3
Line5=0 0 128 0 4
The GraphFont entry specifies the font name and size in points.
The 5 numbers given in the Border, Axis and Line entries are
the Red intensity (0-255), Green intensity, Blue intensity,
Color Linestyle and Mono Linestyle.
Linestyles are 0=SOLID, 1=DASH, 2=DOT, 3=DASHDOT, 4=DASHDOTDOT.
In the example WGNUPLOT.INI file above, Line 2 is a green solid
line in color mode, or a dashed line in monochrome mode.
The default line width is 1 pixel. If Linestyle is negative it
specifies the width of a SOLID line in pixels.
Line1 and any linestyle used with the points style must be
SOLID with unit width.
windows3.0
Windows 3.1 is preferred, but WGNUPLOT will run under Windows 3.0
with the following restrictions:
1. COMMDLG.DLL and SHELL.DLL (available with Windows 3.1 or Borland C++ 3.1)
must be in the windows directory.
2. WGNUPLOT.HLP produced by Borland C++ 3.1 is in Windows 3.1 format.
You need to use the WINHELP.EXE supplied with Borland C++ 3.1.
3. It won't run in real mode due to lack of memory.
4. Truetype fonts are not available in the graph window.
5. Drag-drop does not work.
tics
By default, tics are drawn inwards from the border on all four sides.
The set tics command can be used to change the tics to be
drawn outwards on the left and bottom borders only.
This is useful when doing impulse plots.
Syntax:
set tics {<direction>}
show tics
where <direction> may be in or out. set tics defaults to in.
See also the set xtics, set ytics, and set ztics command for more
control of tic marks and set mxtics, and set mytics for minor tic marks
Using splot, in 3-d plots, one can adjust the relative height of the
vertical (Z) axis using set ticslevel. The numeric argument provided
specifies the location of the bottom of the scale. a zero will put it
on the bottom grid and any positive number somewhere along the z axis.
Syntax:
set ticslevel {<level>}
show tics
where <level> is a non negative numeric argument. For example,
set ticslevel 0.5
sets the tics level to the default value.
See also the set view.
The size of the major tic marks can be adjusted via set ticscale. The
default size is 1.0. Minor tic marks are 0.5*ticscale. Note that it is
possible to have the tic marks pointing outward using a negative size.
Syntax:
set ticscale {<size>}
show tics
time
The optional set time places the time and date of the plot either
at the top or bottom of the left margin. The exact location is
device dependent.
Syntax:
set time {<xoff>}{,<yoff>}
set notime
show time
Specifying constants <xoff> or <yoff> as optional offsets for the time
will move the time <xoff> or <yoff> character screen coordinates. For
example,
set time ,-3
will change only the y offset of the time, moving the title down by
roughly the height of three characters.
timefmt
This command applies to timeseries where data is composed of dates/times.
It has no meaning unless the comand set {x,y,z}data time is given also.
The string argument tells gnuplot how to read timedata from the datafile.
Valid conversion codes are: %d (day of month,1-31), %m (month,1-12),
%y (year,0-99), %Y (year, 4 digits), %j (day of year,1-365), %H (hour,0-24),
%M (minute,0-60), %S (second,0-60). Any character is allowed in the string
(included space), but must match exactly. Backslash-octals (\nnn) is
converted to char, also \t (tab) is understood. If there is no separating
character between the date/time elements, then %d, %m, %y, %H, %M and %S read
2 digits each, %Y read 4 digits and %j reads 3 digits. The columns in the
timedata counts one column in the "using n:n" specification.
See also set {x,y,z}data.
Example:
set timefmt "%d/%m/%Y\t%H:%M"
tells gnuplot to read date and time separated by tab.
Timeseries Demo.
title
The set title command produces a plot title that is centered at the
top of the plot. Using the optional x,y screen offsets, the title
can be placed anywhere on the plot. set title with no parameters
clears the title.
Syntax:
set title {"<title-text>"} {<xoff>}{,<yoff>}
show title
Specifying constants <xoff> or <yoff> as optional offsets for the
title will move the title <xoff> or <yoff> character screen
coordinates. Note these are screen coordinates and not plot
coordinates. For example,
set title ,-1
will change only the y offset of the title, moving the title down by
roughly the height of one character.
Multiline titles is supported by including newlines (\n) in the string.
The string is also scanned for backslash-octal conversion (\nnn), thus
making it possible to include any character in the string.
(The EEPIC, Imagen, Uniplex, LaTeX, and TPIC drivers allow \\ in a string
to specify a newline.)
trange
The set trange command sets the parametric range used to compute
x and y values when in parametric mode. If not in parametric mode
(see set parametric) then this range is not used. This command
does not affect x/y autoscaling or x/y ranges.
This range may also be specified on the plot command line when
in parametric mode.
Syntax:
set trange [{<tmin> : <tmax>}]
where <tmin> and <tmax> terms are constants or expressions or a star
to set autoscale.
Both the <tmin> and <tmax> terms are optional. Anything omitted will
not be changed, so
set trange [:10]
changes tmax to 10 without affecting tmin. See also set urange and
set parametric.
urange
The set urange and set vrange commands sets the parametric ranges used
to compute x, y, and z values when in splot parametric mode. If not in
parametric mode (see set parametric) then these ranges are not used. This
command does not affect x/y autoscaling or x/y ranges.
This range may also be specified on the splot command line when
in parametric mode. See plot for more information
Syntax:
set urange [{<umin> : <umax>}]
where <umin> and <umax> terms are constants or expressions or a star to
set autoscale.
Both the <umin> and <umax> terms are optional. Anything omitted will
not be changed, so
set urange [:10]
changes umax to 10 without affecting umin. See also set trange.
variables
The show variables command lists all user-defined variables and
their values.
Syntax:
show variables
view
The set view command sets the view point for splots. This
command controls the way the 3-d coordinates of the plot are mapped
into the 2-d screen space. This command provides controls to both
rotation and scaling of the plotted data but supports orthographic
projections only.
Syntax:
set view <rot_x> {,{<rot_z>}{,{<scale>}{,<scale_z>}}}
show view
where <rot_x> and <rot_z> control the rotation angles (in degrees)
along a virtual 3-d coordinate system aligned with the screen such
that the screen horizontal axis is x, screen vertical axis is y, and
the axis perpendicular to the screen is z. <rot_x> is bounded to the
[0:180] range with a default of 60 degrees, while <rot_z> is bounded
to the [0:360] range with a default of 30 degrees. <scale> controls
the scaling of the entire splot, while <scale_z> scales the z axis
only. Both scales default to 1.0.
Examples:
set view 60, 30, 1, 1
set view ,,0.5
The first sets all the four default values. The second changes
only scale, to 0.5.
See also set ticslevel.
vrange
The set vrange command is similar to the set urange command.
Please see set urange.
xdata
This command sets the datatype on the xaxis to date/time. See set timefmt
to tell gnuplot how to read the data. The date/time is converted to seconds
from start of the century. There is currently only one timefmt, which implies
that all the date/time columns must confirm to this format. Specification of
ranges should be supplied as qouted strings according to this format to avoid
interpretation of the date/time as expression.
The function "strftime" (do "man strftime" to look it up) is used to print
ticmark labels. Gnuplot tries to figure out a resonable format for this
unless the set format x "string" has supplied something that does not look
like a decimal format (more than one '%' or not %f nor %g).
Syntax:
set xdata time
To turn the xaxis data back to the default:
set xdata
xlabel
The set xlabel command sets the x-axis label that is centered along
the x axis. Using the optional x,y screen offsets, the label can be
placed anywhere on the plot. set xlabel with no parameters clears
the label. The string is scanned for backslash-octal (\nnn) conversion.
Syntax:
set xlabel {"<label>"} {<xoff>}{,<yoff>}
show xlabel
Specifying constants <xoff> or <yoff> as optional offsets for the
label will move the label <xoff> or <yoff> character screen
coordinates. For example,
set xlabel -1
will change only the x offset of the xlabel, moving the label roughly
one character width to the left.
Multiline label is achieved by simply putting a linefeed in the text (\n).
Example:
set xlabel "This is the first line.\nThe second.\nThe third."
(The EEPIC, Imagen, LaTeX, and TPIC drivers allow \\ in a string to specify
a newline.)
xmargin
This command gives control over the xaxis offset. If this is not given,
gnuplot computes the offset based on the number of lines in the ylabel
and the length of the ytic marks (plot, not splot). The margin units is
character.
Syntax:
set xmargin <chars>
sets the margin.
set xmargin
sets the margin back to computed.
xrange
The set xrange command sets the horizontal range that will be
displayed. This command turns x axis autoscaling off.
This range may also be specified on the plot command line.
Syntax:
set xrange [{<xmin> : <xmax>}]
where <xmin> and <xmax> terms are constants or expressions or a star to
set autoscaling. If xdata is date/time give the range as a quoted string
according to the set timefmt format.
Both the <xmin> and <xmax> terms are optional. Anything omitted will
not be changed, so
set xrange [:10]
changes xmax to 10 without affecting xmin (may still be autoscaled).
And
set xrange [:*]
sets autoscaling in the xmax direction.
xtics
Fine control of the x axis tic marks is possible with the
set xtics command. The x-axis tic marks may be turned off with the
set noxtics command. They may be turned on (the default state) with
set xtics.
Syntax:
set xtics { {<start>, <incr>{, <end>}} |
{({"<label>"} <pos> {, {"<label>"} <pos>}...)} }
set noxtics
show xtics
The <start>, <incr>, <end> form specifies that a series of tics will
be plotted on the x axis between the x values <start> and <end>
with an increment of <incr>. If <end> is not given it is assumed to be
infinity. The increment may be negative. For example,
set xtics 0,.5,10
makes tics at 0, 0.5, 1, 1.5, ..., 9.5, 10.
The ("<label>" <pos>, ...) form allows arbitrary tic positions or
non-numeric tic labels. A set of tics are a set of positions, each
with its own optional label. Note that the label is a string enclosed
by quotes, and may be a constant string, such as "hello", or contain
formatting information for the tic number (which is the same as the
position), such as "%3f clients". See set format for more
information about this case. The label may even be empty.
Examples:
set xtics ("low" 0, "medium" 50, "high" 100)
set xtics (1,2,4,8,16,32,64,128,256,512,1024)
set xtics ("bottom" 0, "" 10, "top" 20)
Tics will only be plotted when in range.
In case of timeseries data position values must be given as qouted
dates-times according to the format timefmt.
mxtics
Minor tic marks are the default along the x-axis. The number of minor tics
between major tic marks can be adjusted. Minor tic marks are turned off with
set nomxtics.
Syntax:
set mxtics {<freq>}
set nomxtics
show mxtics
<freq> is the number of sub-intervals (NOT number of minor tics!) between
major tics (10 is default so there are 9 minor tics between major tics).
mytics
Minor tic marks are the default along the y-axis. The number of minor tics
between major tic marks can be adjusted. Minor tic marks are turned off with
set nomytics.
Syntax:
set mytics {<freq>}
set nomytics
show mytics
<freq> is the number of sub-intervals (NOT number of minor tics!) between
major tics (10 is default so there are 9 minor tics between major tics).
xdtics
The set xdtics commands converts the x axis tic marks to days of
the week where 0=Sun and 6=Sat. Overflows are converted modulo 7
to dates.
Examples:
set xdtics
Sets x axis tics in days.
The set ydtics set zdtics and set noydtics set nozdtics commands
work identically.
See also the set format command.
xmtics
The set xmtics commands converts the x axis tic marks to months of
the years where 1=Jan and 12=Dec. Overflows are converted modulo 12
to months.
Examples:
set xmtics
Sets x axis tics into months.
The set ymtics set zmtics and set noymtics set nozmtics commands
work identically.
See also the set format command.
xzeroaxis
set xzeroaxis draws the x-axis. By default, this option is on.
set noxzeroaxis causes GNUPLOT to omit the x-axis.
Syntax:
set xzeroaxis
set noxzeroaxis
show xzeroaxis
ydata
Sets yaxis data to timeseries (dates/times). See set xdata.
ylabel
The set ylabel command sets the y-axis label. The position of this
label depends on the terminal, and can be one of the following three
positions (the position can be adjusted with optional parameters).
1. Horizontal text flushed left at the top left of the plot.
Terminals that cannot rotate text will probably use this method.
2. Vertical text centered vertically at the left of the plot.
Terminals that can rotate text will probably use this method.
3. Horizontal text centered vertically at the left of the plot.
The EEPIC, LaTeX and TPIC drivers use this method. The user must insert
line breaks using \\ to prevent the ylabel from overwriting
the plot. To produce a vertical row of characters, add \\
between every printing character (but this is ugly).
Syntax:
set ylabel {"<label>"} {<xoff>}{,<yoff>}
show ylabel
With no parameters, the label is cleared. Specifying constants <xoff>
or <yoff> as optional offsets for the label will move the label <xoff>
or <yoff> character screen coordinates. For example,
set ylabel -1
will change only the x offset of the ylabel, moving the label roughly
one character width left of its default position. This is especially
useful with the LaTeX driver.
Multiline ylabel is supported, put a newline in the string (\n). The string
is also scanned for backslash-octal (\nnn) conversion.
(The EEPIC, Imagen, LaTeX, and TPIC drivers allow \\ in a string to specify
a newline.)
yrange
The set yrange command sets the vertical range that will be
displayed. This command turns y axis autoscaling off.
This range may also be specified on the plot command line.
Syntax:
set yrange [{<ymin> : <ymax>}]
where <ymin> and <ymax> terms are constants or expressions or a star to
set autoscale.
Both the <ymin> and <ymax> terms are optional. Anything omitted will
not be changed, so
set yrange [:10]
changes ymax to 10 without affecting ymin.
To set ymin and autoscaling i the ymax direction:
set yrange [0:*]
ytics
The set ytics and set noytics commands are similar to the set xtics
and set noxtics commands. Please see set xtics. See set mytics for
minor tic marks along y axis.
ydtics
The set ydtics and set noydtics commands are similar to the set xdtics
and set noxdtics commands. Please see set xdtics.
ymtics
The set ymtics and set noymtics commands are similar to the set xmtics
and set noxmtics commands. Please see set xmtics.
yzeroaxis
set yzeroaxis draws the y-axis. By default, this option is on.
set noyzeroaxis causes GNUPLOT to omit the y-axis.
Syntax:
set yzeroaxis
set noyzeroaxis
show yzeroaxis
zdata
Set zaxis date to timeseries (dates/times). Please see set xdata.
zero
The zero value is the default threshold for values approaching 0.0.
GNUPLOT will not plot a point if its imaginary part is greater in
magnitude than the zero threshold. Axis ranges cannot be less than
The zero value is the default threshold for values approaching 0.0.
GNUPLOT will not plot a point if its imaginary part is greater in
magnitude than the zero threshold. Axis ranges cannot be less than
zero. The default zero value is 1e-8. This can be changed with
the set zero command.
Syntax:
set zero <expression>
show zero
zeroaxis
set zeroaxis draws the x-axis and y-axis. By default, this option is
on. set nozeroaxis causes GNUPLOT to omit the axes, and is
equivalent to set noxzeroaxis; set noyzeroaxis.
Syntax:
set zeroaxis
set nozeroaxis
show zeroaxis
See set xzeroaxis and set yzeroaxis.
zlabel
The set zlabel command sets the z-axis label that is centered along
the z axis. Using the optional x,y screen offsets, the label can be
placed anywhere on the plot. set zlabel with no parameters clears
the label.
Syntax:
set zlabel {"<label>"} {<xoff>}{,<yoff>}
show zlabel
Specifying constants <xoff> or <yoff> as optional offsets for the
label will move the label <xoff> or <yoff> character screen
coordinates. For example,
set zlabel ,1
will change only the y offset of the zlabel, moving the label roughly
one character height up.
The zlabel will be drawn whenever surfaces or contours are plotted,
in the space above the grid level.
Multiline labels is supported, put a newline (\n) in the string.
Backslash-octal conversion (\nnn) on the string is performed.
Example:
set zlabel "Line one.\nLine two with 8-bit char: \345."
(The EEPIC, Imagen, LaTeX, and TPIC drivers allow \\ in a string to specify
a newline.)
zrange
The set zrange command sets the vertical range that will be
displayed. This command turns z axis autoscaling off. The zrange is
used only by splot and is ignored by plot.
This range may also be specified on the splot command line.
Syntax:
set zrange [{<zmin> : <zmax>}]
where <zmin> and <zmax> terms are constants or expressions or a star to
set autoscale in one direction.
Both the <zmin> and <zmax> terms are optional. Anything omitted will
not be changed, so
set zrange [2:]
changes zmin to 2 without affecting zmax.
set zrange [:*]
sets autoscale in then zmax direaction.
ztics
The set ztics and set noztics commands are similar to the
set xtics and set noxtics commands. Please see set xtics.
zdtics
The set zdtics and set nozdtics commands are similar to the
set xdtics and set noxdtics commands. Please see set xdtics.
zmtics
The set zmtics and set nozmtics commands are similar to the
set xmtics and set noxmtics commands. Please see set xmtics.
shell
The shell command spawns an interactive shell. To return to
GNUPLOT, type logout if using VMS, exit or the END-OF-FILE
character if using Unix, endcli if using AmigaDOS, or exit if
using MS-DOS or OS/2.
A single shell command may be spawned by preceding it with the !
character ($ if using VMS) at the beginning of a command line.
Control will return immediately to GNUPLOT after this command is
executed. For example, in VMS, AmigaDOS, MS-DOS or OS/2,
! dir
prints a directory listing and then returns to GNUPLOT.
On an Atari, the ! command first checks whether a shell is already
loaded and uses it, if available. This is practical if GNUPLOT is run
from gulam, for example.
splot
Three-dimensional surface and contour plotting is available in
GNUPLOT with the splot command. See the plot command for features
common to the plot command.
See also set contour, set cntrparam, and set surface.
Non parametric Splot Demos
Parametric Splot Demos.
Binary Data
Gnuplot will dynamically determine if a datafile is ASCII or
binary. ASCII data files are discussed in the plot section.
For three dimensions, single precision floats are stored as follows:
<ncols> <x0> <x1> <x2> ...
<y0> <z0,0> <z0,1> <z0,2> ...
<y1> <z1,0> <z1,1> <z1,2> ...
which is converted into triplet:
<x0> <y0> <z0,0>
<x0> <y1> <z0,1>
<x0> <y2> <z0,2>
<x1> <y0> <z1,0>
<x1> <y1> <z1,1>
<x1> <y2> <z1,2>
These triplets are then converted into gnuplot iso_curves and then
uses gnuplot to do the rest of the plotting.
A collection of matrix and vector manipulation routines (in C) are
provided in gnubin.c. The routine to write binary data is
int fwrite_matrix(file,m,nrl,nrl,ncl,nch,row_title,column_title)
An example of using these routines is provided in the file bf_test.c.
The corresponding demo file is demo/binary.dem.
Binary File Splot Demo.
start-up
When GNUPLOT is run, it looks for an initialization file to load.
This file is called .gnuplot on Unix and AmigaDOS systems, and
GNUPLOT.INI on other systems. If this file is not found in the
current directory, the program will look for it in the home directory
(under AmigaDOS, AtariTOS, MS-DOS and OS/2, the environment variable
GNUPLOT should contain the name of this directory). Note: if NOCWDRC
is defined during the installation, GNUPLOT will not read from the
current directory.
If this file is found, GNUPLOT executes the commands in this file.
This is most useful for setting the terminal type and defining any
functions or variables that are used often.
substitution
Command-line substitution is specified by a system command enclosed in
backquotes. This command is spawned and the output it produces
replaces the name of the command (and backquotes) on the command line.
Newlines in the output produced by the spawned command are replaced
with blanks.
Command-line substitution can be used anywhere on the GNUPLOT command
line.
Example:
This will run the program leastsq and replace leastsq (including
backquotes) on the command line with its output:
f(x) = leastsq
or, in VMS
f(x) = run leastsq
update
Syntax: update <filename>
This command updates the start parameter assignments in a start parameter
file as specified in the fit section. Each parameter will be replaced
by its actual value. This is useful for restarting a converged or stopped
fit again.
SEE ALSO: fit
user-defined
New user-defined variables and functions of one through five variables may
be declared and used anywhere.
User-defined function syntax:
<function-name> ( <dummy1> {,<dummy2> {, ...} } ) = <expression>
where <expression> is defined in terms of <dummy1> through <dummy5>.
User-defined variable syntax:
<variable-name> = <constant-expression>
Examples:
w = 2
q = floor(tan(pi/2 - 0.1))
f(x) = sin(w*x)
sinc(x) = sin(pi*x)/(pi*x)
delta(t) = (t == 0)
ramp(t) = (t > 0) ? t : 0
min(a,b) = (a < b) ? a : b
comb(n,k) = n!/(k!*(n-k)!)
len3d(x,y,z) = sqrt(x*x+y*y+z*z)
Note that the variable pi is already defined.
See show functions and show variables.
bugs
The bessel functions do not work for complex arguments.
The gamma function does not work for complex arguments.
There is a bug in the stdio library for old Sun operating systems
(SunOS Sys4-3.2). The "%g" format for 'printf' sometimes incorrectly
prints numbers (e.g., 200000.0 as "2"). Thus, tic mark labels may be
incorrect on a Sun4 version of GNUPLOT. A work-around is to rescale
the data or use the set format command to change the tic mark format
to "%7.0f" or some other appropriate format. This appears to have been
fixed in SunOS 4.0.
Another bug: On a Sun3 under SunOS 4.0, and on Sun4's under Sys4-3.2
and SunOS 4.0, the 'sscanf' routine incorrectly parses "00 12" with
the format "%f %f" and reads 0 and 0 instead of 0 and 12. This
affects data input. If the data file contains x coordinates that are
zero but are specified like '00', '000', etc, then you will read the
wrong y values. Check any data files or upgrade the SunOS.
It appears to have been fixed in SunOS 4.1.1.
Microsoft C 5.1 has a nasty bug associated with the %g format for
printf. When any of the formats "%.2g", "%.1g", "%.0g", "%.g" are
used, printf will incorrectly print numbers in the range 1e-4 to 1e-1.
Numbers that should be printed in the %e format are incorrectly
printed in the %f format, with the wrong number of zeros after the
decimal point.
To work around this problem, use the %e or %f formats explicitly.
GNUPLOT, when compiled with Microsoft C, did not work correctly on two
VGA displays that were tested. The CGA, EGA and VGA drivers should
probably be rewritten to use the Microsoft C graphics library.
GNUPLOT compiled with Borland C++ uses the Turbo C graphics drivers and
does work correctly with VGA displays.
VAX/VMS 4.7 C compiler release 2.4 also has a poorly implemented %g
format for printf. The numbers are printed numerically correct, but
may not be in the requested format. The K&R second edition says that
for the %g format, %e is used if the exponent is less than -4 or greater
than or equal to the precision. The VAX uses %e format if the exponent
is less than -1. The VAX appears to take no notice of the precision
when deciding whether to use %e or %f for numbers less than 1.
To work around this problem, use the %e or %f formats explicitly.
From the VAX C 2.4 release notes:
e,E,f,F,g,G Result will always contain a decimal point.
For g and G, trailing zeros will not be removed from the result.
VAX/VMS 5.2 C compiler release 3.0 has a slightly better implemented
%g format than release 2.4, but not much. Trailing decimal points are
now removed, but trailing zeros are still not removed from %g numbers
in exponential format.
ULTRIX X11R3 has a bug that causes the X11 driver to display "every
other" plot. The bug seems to be fixed in DEC's release of X11R4 so
newer releases of ULTRIX don't seem to have the problem. Solutions for
older sites include upgrading the X11 libraries (from DEC or direct from
MIT) or defining ULTRIX_KLUDGE when compiling the x11.trm file. Note
that the kludge is not an ideal fix, however.
The constant HUGE was incorrectly defined in the NeXT OS 2.0 operating
system. HUGE should be set to 1e38 in plot.h. This error has been
corrected in the 2.1 version of NeXT OS.
Some older models of HP plotters do not have a page eject command 'PG'.
The current HPGL driver uses this command in HPGL_reset. This may need
to be removed for these plotters. The current PCL5 driver uses HPGL/2
for text as well as graphics. This should be modified to use scalable
PCL fonts.
On the Atari version, it is not possible to send output directly to
the printer (using /dev/lp as output file), since CRs are added to LFs in
binary output. As a workaround write the output to a file and copy it to
the printer afterwards using a shell command.
Please report any bugs to bug-gnuplot@dartmouth.edu.
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