19 Plotting with other packages

CURSA contains only limited facilities for plotting: there are the applications for generating finding charts described in Section 18 and both xcatview (see Section 11) and catview (see Section 12) can plot simple scatter-plots and histograms. For more sophisticated plots it is necessary to export the columns to be plotted into specialised plotting packages. Both xcatview and catview can generate output files suitable for input to plotting packages. Usually such files should consist of just the table of values to be plotted, with no extraneous annotation or formatting. The example in Section 12.1 and Figure 1 shows how to configure catview to produce such an output file.

Several plotting packages are available on Starlink. One such is PONGO, which is documented in SUN/137[17]. Figures 5 and 6 show two example PONGO scripts for producing plots. Figure 5 produces a scatter-plot of redshift against V magnitude from a table where the V magnitude is read from the fifth column and the redshift from the fourth. Figure 6 produces an all-sky plot using a PONGO Aitoff projection. Here the celestial coordinates are read from the second and third columns in the table.

  proc scatter
     BEGPLOT xwindows
     READF xcol=5 ycol=4 all RESET
     POINTS 17
     LABEL ’V magnitude’ ’Redshift’ ’Redshift against V’

Figure 5: Procedure to produce a PONGO scatter-plot

  proc aitoff
     BEGPLOT xwindows
     EXPAND 0.7
     READF xcol=2 ycol=3 all RESET
  { Aitoff projection.
     MTEXT T 1.0 0.5 0.5 ’Aitoff centre \ga=12\uh\d \gd=0\(2729)’
     POINTS 17

Figure 6: Procedure to produce a PONGO Aitoff all-sky plot

You can use these examples as a basis for your own scripts. They are simple text files prepared with an editor; either type them in ab ovo or paste them from the Latex source for this document, and modify as appropriate.

To run a PONGO script enter the following commands.

start ICL; the prompt will change to ‘ICL>’.
load scatter
load the PONGO procedure (here assumed to have file name scatter.icl; substitute the name of your file as appropriate).
run the procedure. Again substitute the name of your file as appropriate.
leave ICL.

Alternatively you can use PONGO interactively to assemble the required plot. Many more options are available than are described here. They are fully documented in SUN/137.