[gdal-dev] Return codes in gdalwarp

[Christopher Barker]

Michal Migurski wrote:
> The GTiff files that I 
> might see as input to this script include palette and non-palette 
> images,

> This didn't work with palette images, for which I 
> got an error like: "ERROR 1: JPEGSetupEncode:PhotometricInterpretation 3 
> not allowed for JPEG"

Enhanced error reporting would be great, but this particular issue could 
(should) be addressed in another way.

It's a pretty common case that visual images can be stored either as 
palette or RGB(A). However, when you want to re-size, or warp an image, 
palette often doesn't work well -- you'll generally get a better image 
if you allow interpolated (anti-aliased) colors.

In your case, I'd probably convert all the palette images to RGB, then 
do your warping, which would solve your compression issue, as well as 
give you better results.

It would be nice if GDAL could (optionally) do this on-the0fly 
internally, when  re-scaling or warping images, but I don't think it can 
(am I wrong?)

-Chris


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Christopher Barker, Ph.D.
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