[Gdal-dev] JPEG and EXIF tags

[Frank Warmerdam]

On 6/20/05, Peng Gao <pgao at esri.com> wrote:
> 
> 
> Some digital cameras can output JPEG images with EXIF (Exchangeable
> image file format) tags. Is it possible to get these tags through GDAL
> as
> metadata (name=value pairs)?

Peng,

Currently it is fairly clumsy to read EXIF information with libtiff, because
though the EXIF information is stored in a TIFF directory it is not a
proper "image" directory making it hard to access with TIFFReadDirectory().

I believe that Andrey Kiselev is working on improving that situation in
libtiff, after which it would be easier for GDAL to access EXIF information.
If, in the meantime, it is quite critical to support reading EXIF info I 
could hack a custom directory reader into the GDAL TIFF driver but it
would be at least a few hours of work. 

I too am keen on getting access to the EXIF info from within GDAL.  I
heard about some interesting projects being done with GPS enabled
digital cameras last week, which I believe bundle the location 
information (as well as timestamps and other info) in EXIF packets. 

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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