Functions for display of images in external viewer SOG (http://www.starlink.ac.uk/sog/).
sog( label, loc )
labelmay be any string which identifies the window for display, so that multiple images may be displayed in different windows without getting in each others' way.
locshould be a filename or URL, pointing to an image in a format that SOG understands (this includes FITS, compressed FITS, and NDFs).
label(String): identifies the window in which the image will be displayed
loc(String): image location