Composite Hardcopy Plots

KAPPA applications are modular so that you can build up more-complicated plots, and possibly add annotations with other packages especially PONGO. This is fine if the device is some sort of screen. However, when it is a hardcopy device, PGPLOT ref puts the output from a command into a single disk file. So how do you get the composite plot out on paper? Well you can't just append these files to create a single output.

What you must do is as follows.

• Select an encapsulated PostScript device, be it colour or monochrome.
• Produce your graphics, being careful to rename the output file (usually pgplot.ps) created by each command to avoid it being over-written by the output from the next command. Alternatively, you can specified the device to use separately when running each command, including an explicit unique file name in each device specification (see above).
• Use PSMERGE (the Starlink version, usually in /star/bin) to combine the plots.

To give an example, suppose we wanted to overlay a contour plot on an image.

    % gdset epsfcol_l
    % display $KAPPA_DIR/comwest lut=$KAPPA_DIR/spectrum_lut mode=ra axes
    % mv pgplot.ps display.ps
    % contour noclear mode=au noaxes \\
    % mv pgplot.ps contour.ps
    % psmerge display.ps contour.ps  > myplot.ps
    % rm display.ps contour.ps 

or alternatively:

    % display $KAPPA_DIR/comwest device="epsfcol_l;display.ps" \
              lut=$KAPPA_DIR/spectrum_lut mode=ra axes
    % contour noclear device="epsfcol_l;contour.ps" mode=au noaxes \\
    % psmerge display.ps contour.ps  > myplot.ps
    % rm display.ps contour.ps 

You then print myplot.ps to the colour PostScript printer. PSMERGE also has options for scaling and rotating plots.