[Gdal-dev] Using gdalwarp with paletted tiffs

[Brent Fraser]

Frank,

  I've been trying to use gdalwarp (v1.3.1.0) to mosaic paletted tiffs.
gdalwarp creates the target file and fills in the pixels from the first
source file, but does not fill in pixels from the second file (no error
message is generated).  This behaviour is the same if I switch the sequence
of the files (to test that the coordinate systems and extents are ok); the
first source file's pixels are written, but not the second.

I suspect the problem is related to the palettes.  The palettes of the
source files are identical, and I use nearest neighbor resampling when
creating the target so there should be no "color matching" problem between
the source images (or the target).

Here are the commands:

gdalwarp  -t_srs "+proj=utm +zone=10 +nadgrids=NTv2_0.gsb +datum=NAD83"  -tr
5 5   -te 529915 6317245 560995 6345910 094A13.tif 094G01NC.tif
gdalwarp 094H04.tif 094G01NC.tif


Any ideas?

Thanks!
Brent Fraser
GeoAnalytic Inc.
Calgary, Alberta