Plotting overlaid ellipses

Using PISAPLOT to overlay ellipses is achieved using the OVERLAY and CLEAR parameters. The image over which the plot is to be overlaid should have been displayed using the KAPPA DISPLAY or a routine which uses AGI to store its graphics information (such as PISAGREY).

   # display in=frame mode=per percentiles=[1,99] device=xw
   # pisaplot results=pisafind.dat overlay device=xw

If a device with a suitable overlay is used then the overlay plane may be erased prior to the plotting of the ellipses using the CLEAR parameter.

   # pisaplot results=pisafind.dat overlay clear device=xov

The colour of the ellipses is controlled using the PALNUM parameter. So for instance if one had two lists of results which are separated into stars and galaxies for instance (or one could have PISAFIND results files separated by intensity, ellipticity etc.)

   # pisaplot results=stars.dat overlay palnum=3
   # pisaplot results=galaxies.dat overlay palnum=4

This sequence of commands would result in the data in file stars.dat being overlaid and coloured green. The data in file galaxies.dat would also be overlaid on the same image and coloured blue. The colours of these could then be altered using the KAPPA palette facilities for pens 3 and 4.