Yep, I've got problems with r.in.tiff too. It imports without complaints, but
then I wind up with a file full of zeroes. I'm saving the tiff at normal size,
uncompressed, using XV. Should this provide a palette?
If the map is all zeros, chances are the tiff is a "true color"
image which does NOT have a palette. Try using the -v (verbose)
option with r.in.tiff and see if it says something like
"true color not yet supported". If this is the case, you might be
able to use the pnmtools to quantify the colors, but I haven't
tried that.
The tiff I had with a palette produced a map with various values, but
did not make the GRASS color table correctly. I have since
converted a different tiff with a palette and it correctly make
the color table. Must be a few different kinds of tiffs with
palettes or something.
What works for me is to convert tiff to ppm (I use SDSC imtools),
then use r.in.ppm.
- Bill