<!DOCTYPE html><html><head><title></title></head><body><div style="font-family:Arial;">Hi,</div><div style="font-family:Arial;"><br></div><div style="font-family:Arial;">I have a NetCDF-style product with a separate geolocation dataset I'm trying to convert to something more easy to work with. Not sure if it matters, but the geolocation arrays are scaled. I tried to unscale them first:</div><div style="font-family:Arial;"><br></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;">$ cat lat.vrt</span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"><VRTDataset rasterXSize="4865" rasterYSize="4090"></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> <VRTRasterBand dataType="Float32" band="1" blockXSize="973" blockYSize="818"></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> <NoDataValue>-2147483648</NoDataValue></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> <Scale>1e-06</Scale></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> <SimpleSource></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> <SourceFilename relativeToVRT="1">NetCDF:geo_coordinates.nc:latitude</SourceFilename></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> <SourceBand>1</SourceBand></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> <SourceProperties RasterXSize="4865" RasterYSize="4090" DataType="Int32" BlockXSize="973" BlockYSize="818" /></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> <SrcRect xOff="0" yOff="0" xSize="4865" ySize="4090" /></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> <DstRect xOff="0" yOff="0" xSize="4865" ySize="4090" /></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> </SimpleSource></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> </VRTRasterBand></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"></VRTDataset></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"></span><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"><br></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;">$ gdal_translate -unscale -ot Float32 lat.vrt lat.tif</span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"><br></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"># same for lon.{vrt,tif}</span></div><div style="font-family:Arial;"><br></div><div style="font-family:Arial;">Then I made a VRT for the main dataset:</div><div style="font-family:Arial;"><br></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"><VRTDataset rasterXSize="4865" rasterYSize="4090"></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> <Metadata domain="GEOLOCATION"></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> <MDI key="X_DATASET">lon.tif</MDI></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> <MDI key="X_BAND">1</MDI></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> <MDI key="Y_DATASET">lat.tif</MDI></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> <MDI key="Y_BAND">1</MDI></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> <MDI key="PIXEL_OFFSET">0</MDI></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> <MDI key="LINE_OFFSET">0</MDI></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> <MDI key="PIXEL_STEP">1</MDI></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> <MDI key="LINE_STEP">1</MDI></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> </Metadata></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> <VRTRasterBand dataType="UInt16" band="1" blockXSize="1217" blockYSize="1023"></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> <NoDataValue>65535</NoDataValue></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> <Scale>0.01394645962864161</Scale></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> <SimpleSource></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> <SourceFilename relativeToVRT="1">Oa01_radiance.nc</SourceFilename></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> <SourceBand>1</SourceBand></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> <SourceProperties RasterXSize="4865" RasterYSize="4090" DataType="UInt16" BlockXSize="1217" BlockYSize="1023" /></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> <SrcRect xOff="0" yOff="0" xSize="4865" ySize="4090" /></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> <DstRect xOff="0" yOff="0" xSize="4865" ySize="4090" /></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> </SimpleSource></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> </VRTRasterBand></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"></VRTDataset></span></div><div style="font-family:Arial;"><br></div><div style="font-family:Arial;">The coordinates look fine in the two TIFFs:</div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"><br></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;">$ gdalinfo -stats lat.tif<br></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;">Driver: GTiff/GeoTIFF</span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;">Files: lat.tif</span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;">Size is 4865, 4090</span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;">Image Structure Metadata:</span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> INTERLEAVE=BAND</span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;">Corner Coordinates:</span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;">Upper Left ( 0.0, 0.0)</span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;">Lower Left ( 0.0, 4090.0)</span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;">Upper Right ( 4865.0, 0.0)</span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;">Lower Right ( 4865.0, 4090.0)</span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;">Center ( 2432.5, 2045.0)</span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;">Band 1 Block=4865x1 Type=Float32, ColorInterp=Gray</span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> Minimum=39.552, Maximum=52.456, Mean=46.179, StdDev=3.112</span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"><br></span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;">$ gdalinfo -stats lon.tif</span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;">Driver: GTiff/GeoTIFF</span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;">Files: lon.tif</span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;">Size is 4865, 4090</span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;">Image Structure Metadata:</span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> INTERLEAVE=BAND</span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;">Corner Coordinates:</span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;">Upper Left ( 0.0, 0.0)</span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;">Lower Left ( 0.0, 4090.0)</span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;">Upper Right ( 4865.0, 0.0)</span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;">Lower Right ( 4865.0, 4090.0)</span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;">Center ( 2432.5, 2045.0)</span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;">Band 1 Block=4865x1 Type=Float32, ColorInterp=Gray</span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> Minimum=16.249, Maximum=36.250, Mean=25.532, StdDev=4.917</span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> NoData Value=-2.1474836e+09</span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> Metadata:</span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> STATISTICS_MINIMUM=16.248615264893</span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> STATISTICS_MAXIMUM=36.24991607666</span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> STATISTICS_MEAN=25.532068327481</span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> STATISTICS_STDDEV=4.9167101776381</span></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;"> STATISTICS_VALID_PERCENT=100</span></div><div style="font-family:Arial;"><br></div><div style="font-family:Arial;">However, this fails with "Warning 1: Too many points (529 out of 529) failed to transform, unable to compute output bounds.":</div><div style="font-family:Arial;"><br></div><div style="font-family:Arial;"><span class="font" style="font-family:menlo, consolas, monospace, sans-serif;">$ gdalwarp -geoloc -t_srs EPSG:4326 Oa01.vrt Oa01.tif</span></div><div style="font-family:Arial;"><br></div><div style="font-family:Arial;">The files are available at <a href="https://nas.dend.ro/browse/datasets/Oa01.zip">https://nas.dend.ro/browse/datasets/Oa01.zip</a>, if anyone can to take a look.</div><div style="font-family:Arial;"><br></div><div style="font-family:Arial;">Thanks,</div><div style="font-family:Arial;">Laurentiu<br></div></body></html>