Hi Javier I regularly use PROJ for that. It’s a bit of a hack but it works. Here’s a demonstration using the DVR90_2023 geoid. The lower left grid point is at (7,53.5) and the horizontal grid spacing is 0.1 degree. Below I first get the actual grid values at two adjacent grid points and then lastly interpolate the grid value in between those two points:
echo 7 53.5 | cct -t0 -z0 +proj=vgridshift +grids=dk_sdfi_dvr90_2023.tif +multiplier=1 7.0000000000 53.5000000000 40.2720 0.0000 (fire-dev) C:\Temp\fire\obs-beregning>echo 7 53.51 | cct -t0 -z0 +proj=vgridshift +grids=dk_sdfi_dvr90_2023.tif +multiplier=1 7.0000000000 53.5100000000 40.2590 0.0000 (fire-dev) C:\Temp\fire\obs-beregning>echo 7 53.505 | cct -t0 -z0 +proj=vgridshift +grids=dk_sdfi_dvr90_2023.tif +multiplier=1 7.0000000000 53.5050000000 40.2655 0.0000 The grid values are obviously the third component of the output coordinates. /Kristian From: gdal-dev <gdal-dev-boun...@lists.osgeo.org> On Behalf Of Javier Jimenez Shaw via gdal-dev Sent: 24. april 2024 10:33 To: gdal dev <gdal-dev@lists.osgeo.org> Subject: [gdal-dev] Reading interpolated values on DSM Hi I would like to read in QGIS or GDAL an interpolated value in a DSM (well, actually it is a geoid model, but it is the same behaviour). See that I do not want the pixel value, but the linear interpolation among the neighbour pixels, assuming that the pixel value is in the center of the pixel. For instance, this file https://www.isgeoid.polimi.it/Geoid/Asia/Japan/japan2000_g.html Is there any way to get it (without implementing the interpolation myself)? If I understood correctly gdallocationinfo is not interpolating, just giving the pixel value. Thanks .___ ._ ..._ .. . ._. .___ .. __ . _. . __.. ... .... ._ .__
_______________________________________________ gdal-dev mailing list gdal-dev@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/gdal-dev
