Chapter 4: Plotting Axis Systems and Titles

4.1 Plotting Axis Systems

An axis system defines an area on the page for plotting data. Various axis systems can be plotted to accommodate different applications. For two-dimensional graphics, a maximum of two parallel X- and Y-axes can be drawn. The axis system is scaled to fit the range of data points and can be labeled with values, names and ticks. Two-dimensional axis systems are plotted with a call to the routine GRAF.

G R A F

GRAF plots a two-dimensional axis system.

The call is:
CALL GRAF (XA, XE, XOR, XSTEP, YA, YE, YOR, YSTEP)

XA, XE
are the lower and upper limits of the X-axis.
XOR, XSTEP
are the first X-axis label and the step between labels.
YA, YE
are the lower and upper limits of the Y-axis.
YOR, YSTEP
are the first Y-axis label and the step between labels.
Additional notes:

4.2 Termination of Systems

E N D G R F

The routine ENDGRF terminates an axis system and sets the level back to 1.

The call is:
CALL ENDGRF - level 2, 3

4.3 Plotting Titles

T I T L E

This routine plots a title over an axis system. The title may contain up to four lines of text designated with TITLIN.

The call is:
CALL TITLE - level 2, 3
Additional note:

4.4 Plotting Grid Lines

G R I D

The routine GRID overlays a grid on an axis system.

The call is:
CALL GRID (IXGRID, IYGRID) - level 2, 3

IXGRID, IYGRID
are the numbers of grid lines between labels.
G R D P O L

The routine GRDPOL plots a polar grid.

The call is:
CALL GRDPOL (IXGRID, IYGRID) - level 2, 3

IXGRID
is the numbers of circles between labels.
IYGRID
is the numbers of sector lines between 360 degrees.
A X G I T

The routine AXGIT plots vertical and horizontal lines through X = 0 and Y = 0.

The call is:
CALL AXGIT - level 2, 3
Additional note: C R O S S

The routine CROSS plots vertical and horizontal lines with additional ticks through X = 0 and Y = 0.

The call is:
CALL CROSS - level 2, 3
Additional note:

4.5 Secondary Axes

The following routines plot single X- and Y-axes; they are called secondary axes because they do not define or change any of the axis scaling parameters. Secondary axes can be used to add additional labels to the axis systems.

The plotting routines for secondary axes are:

The call is:
CALL XAXIS (A, B, OR, STEP, NL, CSTR, IT, NX, NY)

A, B
are the lower and upper limits of the axis.
OR, STEP
are the first label and the step between labels.
NL
is the length of the axis in plot coordinates.
CSTR
is a character string containing the axis name.
IT
indicates how ticks, labels and the axis name are plotted. If IT = 0, they are plotted in a clockwise direction. If IT = 1, they are plotted in an counter-clockwise direction.
NX, NY
are the plot coordinates of the axis start point. The X-axis will be plotted from left to right and the Y-axis from bottom to top.

Analog:
YAXIS, XAXLG, YAXLG

Additional notes:
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