[gdal-dev] Troubles with PAM file

[Dominique Lyszczarz]

If it can be useful to anyone facing the same issue, my little script for
parsing these aux.xml and writing the expected GDAL commands to rectify the
raster is available here https://github.com/domlysz/PAM-GCPs-warper

Regards

Le mer. 20 mars 2019 à 18:09, Dominique Lyszczarz <domlysz at gmail.com> a
écrit :

> Thank you Even for these informations, that's good to know. I've added the
> .aux.xml in the repository if it can be useful as reference. Finally, I got
> good results with gdal_translate -gcp option following by gdalwarp. Fun
> fact, in the PAM file Y image coordinates are negatives values but must be
> pushed as positive number in gdal_translate command.
>
> Le mer. 20 mars 2019 à 15:57, Even Rouault <even.rouault at spatialys.com> a
> écrit :
>
>> Dominique,
>> >
>> > I'm trying to read a raster georeferenced with ArcGIS. It's a jpg file
>> > coming with a PAM file (.aux.xml) that store GCPs and define a
>> polynomial
>> > transformation of order 3. Unfortunately GDAL does not take the PAM file
>> > into account and gdalinfo does not report GCPs. After some
>> investigations,
>> > I found this commit
>> > <
>> https://github.com/OSGeo/gdal/commit/f8822eb50466fb740e228b8c6a7f066b916faa
>> > 0a> that suggest PAM files are supported by GDAL but only for TIFF
>> dataset.
>>
>> Not really. PAM files are supported for most formats, included JPEG, but
>> the
>> ESRI specific GCP decoding was limited for now to the GTiff format,
>> mostly
>> because of the oddity you noticed: in the case for which this was
>> developed
>> for
>> (see https://lists.osgeo.org/pipermail/gdal-dev/2017-January/045854.html
>> and
>> the related email thread), pixel coordinates were indeed surprisingly in
>> inches and from the bottom left origin. So I couldn't/didn't want to
>> generalize that to core PAM processing.
>>
>> >
>> > I'm a bit confused with theses PAM files, is there any technical doc
>> from
>> > ESRI?
>>
>> Not to my knowledge. Initially PAM was developed for GDAL itself, but it
>> seems
>> ESRI developed some extensions on top of it, like the one you are facing
>> to.
>>
>> > The file can be downloaded here :
>> >
>> https://drive.google.com/drive/folders/1hZXncJhcfZI0Uem-oCfUsruO9mPwWD0U?usp
>> > =sharing
>>
>> You didn't include the most interesting part, that is the .aux.xml file
>> itself
>>
>> Even
>>
>> --
>> Spatialys - Geospatial professional services
>> http://www.spatialys.com
>>
>
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