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. _______________________________________________ gdal-dev mailing list [email protected] https://lists.osgeo.org/mailman/listinfo/gdal-dev
