From CASA Guides
Help on viewer task:
VIDEO: Joe McMullin has recorded a short video introducing the basics of viewer. The GUI has changed only a little since that video was made.
The help file follows.
View an image or visibility data set: examples of usage: viewer viewer "myimage.im" viewer "mymeasurementset.ms" viewer "myrestorefile.rstr" viewer "myimage.im", "contour" viewer "'myimage1.im' - 2 * 'myimage2.im'", "lel" Keyword arguments: infile -- Name of file to visualize default: '' example: infile='ngc5921.image' If no infile is specified the Load Data window will appear for selecting data. displaytype -- (optional): method of rendering data visually (raster, contour, vector or marker). You can also set this parameter to 'lel' and provide an lel expression for infile (advanced). default: 'raster' example: displaytype='contour' Note: there is no longer a filetype parameter; typing of data files is now done automatically. example: viewer infile='my.ms' obsolete: viewer infile='my.ms', filetype='ms'