[gdal-dev] Problem reading Sentinel-1 GeoTIFFs

[Simon Eves]

Dear Even,

Thank you, yet again, for a quick resolution. I cherry-picked that change
over to my 3.4.0 build and it certainly gets rid of the Proj errors.

I also found the mistake in the rest of my code that was creating the large
values (I had bDstToSrc set to true on the GDALGCPTransform call for some
reason).

All working now! :)

SE



On Fri, Dec 10, 2021 at 3:40 PM Even Rouault <even.rouault at spatialys.com>
wrote:

> Those files use a invalid GeogEllipsoidGeoKey=4326 for the WGS 84
> ellipsoid. The correct code should be 7030. Sometimes should report that to
> the data producer.
>
> Warning silenced in https://github.com/OSGeo/gdal/pull/4975
> Le 11/12/2021 à 00:05, Simon Eves a écrit :
>
> After also finding this thread...
>
>   https://github.com/OSGeo/gdal/issues/2321
>
> ...I installed geotiff-bin and ran listgeo on the file.
>
> It also spits the same message (three times).
>
> The output is attached.
>
> S
>
> On Fri, Dec 10, 2021 at 2:56 PM Simon Eves <simon.eves at omnisci.com> wrote:
>
>> Further to my earlier post about GCP Transforms, I now have that code
>> written, and it seems to be functioning fine, although whether it's
>> generating the right values is as yet unclear.
>>
>> The problem is that I am having trouble creating the secondary
>> transformation from whatever the output space of the GCP transform is, to
>> my desired space (4326 in this case).
>>
>> Whenever I call GetGCPSpatialRef() on the datasource, I get the following
>> error (twice)
>>
>>   PROJ: proj_create_from_database: ellipsoid not found (1)
>>
>> I get the same error (also twice) when I run gdalinfo on the file, but
>> then with a plausible looking SR dump, which may of course just be a
>> default:
>> ______________________________________________________
>>
>> $ gdalinfo
>> s1b-iw-grd-vv-20211110t033513-20211110t033538-029520-0385e8-001.tiff
>> ERROR 1: PROJ: proj_create_from_database: ellipsoid not found
>> ERROR 1: PROJ: proj_create_from_database: ellipsoid not found
>> Driver: GTiff/GeoTIFF
>> Files:
>> s1b-iw-grd-vv-20211110t033513-20211110t033538-029520-0385e8-001.tiff
>> Size is 25541, 16650
>> GCP Projection =
>> GEOGCRS["WGS 84",
>>     DATUM["World Geodetic System 1984",
>>         ELLIPSOID["unnamed",6378137,298.25722356049,
>>             LENGTHUNIT["metre",1]]],
>>     PRIMEM["Greenwich",0,
>>         ANGLEUNIT["degree",0.0174532925199433]],
>>     CS[ellipsoidal,2],
>>         AXIS["geodetic latitude (Lat)",north,
>>             ORDER[1],
>>             ANGLEUNIT["degree",0.0174532925199433]],
>>         AXIS["geodetic longitude (Lon)",east,
>>             ORDER[2],
>>             ANGLEUNIT["degree",0.0174532925199433]],
>>     ID["EPSG",4326]]
>> Data axis to CRS axis mapping: 2,1
>> GCP[  0]: Id=1, Info=
>>           (0,0) -> (45.0323375081341,62.6475859336067,149.992539359257)
>> [etc.]
>> ______________________________________________________
>>
>> My constructed OGRCoordinateTransformation for the second transform is
>> therefore a no-op, but the final values (which are therefore just the
>> values out of the GCP transform) are definitely not 4326.
>> ______________________________________________________
>>
>> omnisql> select * from s1 where rowid<10;
>> raster_lon|raster_lat
>> 476788.1263799404|747980.9704571336
>> 460813.8583986053|747120.1413700345
>> 444852.7791957706|746184.4282221086
>> 428904.8887714364|745173.8310133558
>> 412970.1871256025|744088.349743776
>> 397048.6742582691|742927.9844133693
>> 381140.3501694361|741692.7350221358
>> 365245.2148591036|740382.6015700753
>> 349363.2683272713|738997.5840571877
>> 333494.5105739397|737537.6824834733
>> ______________________________________________________
>>
>> Those are the first ten pixels of the first scanline of the (~25K x ~16K)
>> file, btw, so intuitively there is something worrying me about those values
>> anyway (they are moving very quickly and non-linearly considering that's
>> just ten pixels).
>>
>> Anyway, some Googling led me to...
>>
>>   https://gitlab.orfeo-toolbox.org/s1-tiling/s1tiling/-/issues/46
>>
>> ...which seems very related, and even mentions a patch to libGeoTIFF by
>> Even. I checked, and that patch IS in the (internal, as configured in the
>> build) GeoTIFF in our GDAL.
>>
>> This is with GDAL 3.4.0 and Proj 7.2.1.
>>
>> Thanks in advance,
>>
>> Simon
>>
>> --
>> <http://www.omnisci.com/>
>> Simon Eves
>> Senior Graphics Engineer, Rendering Group
>> 100 Montgomery St (5th Floor), San Francisco, CA 94104, USA
>>
>>
>> Email: simon.eves at omnisci.com | Cell:  +1 (415) 902-1996
>>
>>
>
> --
> <http://www.omnisci.com/>
> Simon Eves
> Senior Graphics Engineer, Rendering Group
> 100 Montgomery St (5th Floor), San Francisco, CA 94104, USA
>
>
> Email: simon.eves at omnisci.com | Cell:  +1 (415) 902-1996
>
>
> _______________________________________________
> gdal-dev mailing listgdal-dev at lists.osgeo.orghttps://lists.osgeo.org/mailman/listinfo/gdal-dev
>
> -- http://www.spatialys.com
> My software is free, but my time generally not.
>
>

-- 
<http://www.omnisci.com/>
Simon Eves
Senior Graphics Engineer, Rendering Group
100 Montgomery St (5th Floor), San Francisco, CA 94104, USA


Email: simon.eves at omnisci.com | Cell:  +1 (415) 902-1996
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