[gdal-dev] Troubles with PAM file

[Dominique Lyszczarz]

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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