raster image preprocessing problem.

[Zhonghai Wang]

Hi there,

I have a couple of GIFs with wld files, but the original Projection is not
the one I want, I tried to use the Proj4 to reproject them on-the-fly, but
it takes really long to perform the map request, therefore I tried
to preprocess the images with GDAL tools, but I've got some problems here:

1. problem with gdalwarp: trying to mosaic the images into one output file,
but only the first image has the correct image color, the other images are
rendered with strange colors, is this a common problem if using gdalwarp to
mosaic images?

2.problem with gdal_merge.py: after trying the gdalwarp command, I've tried
the gdal_merge.py command to merge all the images together with the -pct
parameter, unfortunately, the merged image is the same as the first try. is
it possible to merge images using the command with the correct color table?

BTW: I can not use the gdal_translate command, since there are gaps between
the reprojected images.

thanks for your info.

zhonghai
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