[Geotiff] tiffcrop -> geotiffcrop, is it possible?

[Gennady Khokhorin]

Frank,
Not long ago tifflib mailing list got a message about new tiffcrop
utility. I found it very useful, in my case I need to clip area of interest
in aerial photo and store result outside for delivery.
I'm wonder if it is possible to reproduce this utility in form of
geotiffcrop to keep georeference as well.

One approach would be to handle coordinates in twf world file. But will be
much better to update all georef info.

If it is possible I would put request for such command in the wish list.

Thanks,
Gennady


Tiff list readers,
I have a working version of a new utility called tiffcrop that is based 
on tiffcp. It adds cropping by specifying margins, fixed sized regions, 
and zones that are portions of the image, ie 1/4, 1/2, etc from a 
specified reference edge. I've added rotation by 90,180, or 270 degrees 
and mirroring horizontally or vertically. All of these can be applied 
to the entire image or just a crop region. I have tested with bilevel, 8 
bit grayscale, 8 bit palette, 8 bit RGB, 8 bit RGBA images successfully. 
The only image that I can't seem to handle is an 8 bit YCbCr with 3 
samples per pixel from the libtiff test pics set, dscf0013.tif.
Does anyone have any information on how YCbCr images are handled by the 
read[Separate/Contig][Strips/Tiles]IntoBuffer routines in tiffcp that 
would be different for YCbCr data rather than RGBA data?
Since the source file is too large to send to the Tiff list, I can send 
the source file or a diff against tiffcp.c to anyone who is interested 
in testing the code. The source is 96 K and the diff against tiffcp.c in 
the 3.8.2 distribution is 50 K. Just send me your email address.
Richard Nolde

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