In order to test that I was decoding the binary properly, I wrote the first row of data out to its own little text file and used gnuplot to graph it up.
in my script I have the following:
for i in range(1):
row = struct.unpack('>'+str(ncol)+'h',img.read(2*ncol))
for depth in row:
then in terminal I call gnuplot and at the prompt type:
plot 'filename' with l
Certainly looks like a nice depth profile to me: