Kristian,
https://github.com/OSGeo/gdal/pull/4639 will allow you to use an
arbitrary pipeline to do a vertical transformation through gdalwarp
Even
Le 23/08/2021 à 10:50, Kristian Evers a écrit :
Thanks for your insights, Even! I had a feeling I was pushing the boundaries
here, good to get that confirmed.
The idea of using -s_srs and a correction grid is intriguing. I assume this way
will be easier to implement as well since I don't have to worry as much about
the CRS and extent of my correction grid as when using gdal_calc. The
correction grids I already have are in EPSG:4326 and I assume GDAL is clever
enough to handle that or at least pass the responsibility over to PROJ. I'll
try a few things and report back how it goes.
I'll make sure to add a ticket for extending the scope of gdalwarp to the
3D-space.
/Kristian
-----Original Message-----
From: Even Rouault <[email protected]>
Sent: 20. august 2021 17:30
To: Kristian Evers <[email protected]>; [email protected]
Subject: Re: [gdal-dev] Custom vertical transformations
Regarding your immediate issue, the workaround I see would be that you
use PROJ to create a regular grid that contains the vertical
correction, use gdalwarp to transform it to the exact extent and
resolution of the result of your 2D-only gdalwarp, and finally use
gdal_calc to sum the two.
Well, if you actually create a vertical correction only grid, then you
could just use -s_srs "+proj=longlat +ellps=...
+geoidgrids=your_tif_or_gtx" (or maybe as output, or fix the sign of
the correction in the grid), since the workaround I give above is what
gdalwarp would do. But of course none of this will solve the
time-dependent aspect you need.
--
http://www.spatialys.com
My software is free, but my time generally not.
--
http://www.spatialys.com
My software is free, but my time generally not.
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