The smurf:makemap command allows a mask to be specified that defines background areas on the sky. These background areas are forced to zero on all but the last iteration in order to suppress spurious large scale structures. The user may supply an external NDF to be used as the mask, or alternatively makemap can be left to generate its own mask based (for instance) on the evolving SNR at each pixel. Either way, it is often useful to visualise the mask that was used to create a given map.This can be done using KAPPA commands as follows (assuming the map created by makemap is in file "map.sdf"):
% kappa
% lutgrey
% display map
% contour clear=no mode=free heights=0.5 comp=quality map style='colour=red'
This will display the final map as a greyscale image with the mask outlined in red. Other properites of the mask outline (colour, line thickness, etc) can be specified by including other options in the "style" parameter value when running contour.
