can youy get geotiff out of gimp
ma...@my-deja.com
I have a geotiff file that I want to edit with gimp. I can read it in fine
but when I write it out it seems to have lost its geo reference.
Any ideas what the problem might be?
Thanks in advance for any help.
Merrill McKay
Sent via Deja.com http://www.deja.com/
Before you buy.
Nick Lamb
>Hi all,
>
> I have a geotiff file that I want to edit with gimp. I can read it in fine
>but when I write it out it seems to have lost its geo reference.
What is a geo reference?
> Any ideas what the problem might be?
I would guess that Gimp doesn't know what a geo reference is. Gimp throws
away unknown TIFF tags because it can't safely do anything with them -
they might be specific to the original image, or they may be (as in this
case) something that should be preserved...
If you can suggest something Gimp should do about this I'm open to
suggestions from the group...
Nick.
ma...@my-deja.com
Thanks for your interest. The best way to answer your question
is to point you to the faq site for geotiff
http://gdal.velocet.ca/projects/tiff/geotiff-old/faq.html
Please let me know what you think.
Best Regards
Merrill
In article <slrn8qoefr...@chef.ecs.soton.ac.uk>,
ma...@my-deja.com
I was wondering if you had had a chance to look at the web page I
directed you to and if so what you thought?
Best Regards
Merrill
Nick Lamb
>Hi Nick,
>
> I was wondering if you had had a chance to look at the web page I
>directed you to and if so what you thought?
Ah, convenient. I hadn't got round to looking for your second post after
I read the web pages, because I marked it as read, and it disappeared
off my radar...
My understanding from those pages is that a GeoTIFF tag (or tags?) can
be used to identify exactly which part of the planet an image is of,
and how to correct it so that it can be overlayed or stitched into
a GIS or whatever
This isn't really Gimp's territory but I could make Gimp preserve
GeoTIFF tags when loading, and save them back out if you edit the
image and then save it as TIFF again. The problem is that if you
really savage the image (crop it, flip it, or run lots of filters)
the GeoTIFF tags will be worse than useless..
What exactly were you hoping support for GeoTIFF would let you do? If
I agree to hack support for preserving the tag contents, or someone
else writes the patch, it wouldn't be a priority for 1.2 I'm afraid.
Still, if just preserving the tags is useful to someone, it certainly
could go on the To Do list.
Nick.
ma...@my-deja.com
Thanks for your reply. I have inserted responses between your
comments:
>
> My understanding from those pages is that a GeoTIFF tag (or tags?) can
> be used to identify exactly which part of the planet an image is of,
> and how to correct it so that it can be overlayed or stitched into
> a GIS or whatever
Correct.
>
> This isn't really Gimp's territory but I could make Gimp preserve
> GeoTIFF tags when loading, and save them back out if you edit the
> image and then save it as TIFF again. The problem is that if you
> really savage the image (crop it, flip it, or run lots of filters)
> the GeoTIFF tags will be worse than useless..
True.
>
> What exactly were you hoping support for GeoTIFF would let you do? If
> I agree to hack support for preserving the tag contents, or someone
> else writes the patch, it wouldn't be a priority for 1.2 I'm afraid.
The minimum would be to just preserve the tags regardless. This in
itself would be very helpful.
A more advanced enhancement would be to ask the user if the tags were
still valid if changes were made that distorted the original image.
>
> Still, if just preserving the tags is useful to someone, it certainly
> could go on the To Do list.
It would be.
Thanks again for your interest.
