GT_TOTAL_CNTS extracts the information from the TOTAL_CNTS field which used
the actual spectra to calculate the total number of counts. The routine also
normalizes so that it returns counts/sec. In the first example below, all
four channels are returned, so the output is 4xN. In the second example,
only channel 1 is extracted. It is possible to get a string defining the
channel selected by using the title keyword option.
IDL> x = gt_total_cnts(roadmap)
IDL> x = gt_total_cnts(roadmap,1)
IDL> x = gt_total_cnts(index,2,title=title)