Hi Even, Thanks for the explanation.
I'm not clear on what use case your PR supports. I can't gdalwarp the file - the model expects it in its current format. But if QGIS and etc. can now successfully reproject the file for display, that would be nice. Anyway, now I understand what was happening, and can work around it. I mostly work with the 144x90 file (the one that worked) anyway. Thank you. -k. On 2023-01-23 at 10:39 -05, Even Rouault <even.roua...@spatialys.com> wrote: > Ken, > > if you do "gdalinfo --debug on GLMELT_4X5.OCN.nc", you'll see > > GDAL_netCDF: Latitude/Y is not equally spaced (with a 0.05% tolerance). You > may set the > GDAL_NETCDF_IGNORE_EQUALLY_SPACED_XY_CHECK configuration option to YES to > ignore this check > > and indeed > > $ ncdump -v lat GLMELT_4X5.OCN.nc > [...] > lat = -89, -86, -82, -78, -74, -70, -66, -62, -58, -54, -50, -46, -42, -38, > -34, -30, -26, -22, -18, -14, -10, -6, -2, 2, 6, 10, 14, 18, 22, 26, 30, > 34, 38, 42, 46, 50, 54, 58, 62, 66, 70, 74, 78, 82, 86, 89 ; > > > So you can see the spacing is 4 degree, except for the first and lat > samples where it is 3. So GDAL cannot report a geotransform matrix for > such file. > > I've just submitted https://github.com/OSGeo/gdal/pull/7113 where GDAL > will report a GEOLOCATION metadata domain, that can be used by > gdalwarp to rectify such file > > $ gdalinfo autotest/gdrivers/data/netcdf/GLMELT_4X5.OCN.nc > > [...] > > Geolocation: > GEOREFERENCING_CONVENTION=PIXEL_CENTER > LINE_OFFSET=0 > LINE_STEP=1 > PIXEL_OFFSET=0 > PIXEL_STEP=1 > SRS=GEOGCS["WGS 84",DATUM["WGS_1984",SPHEROID["WGS > 84",6378137,298.257223563,AUTHORITY["EPSG","7030"]],AUTHORITY["EPSG","6326"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9122"]],AXIS["Latitude",NORTH],AXIS["Longitude",EAST],AUTHORITY["EPSG","4326"]] > X_BAND=1 > X_DATASET=NETCDF:"autotest/gdrivers/data/netcdf/GLMELT_4X5.OCN.nc":lon > Y_BAND=1 > Y_DATASET=NETCDF:"autotest/gdrivers/data/netcdf/GLMELT_4X5.OCN.nc":lat > > Even > > Le 23/01/2023 à 13:46, Ken Mankoff a écrit : >> wgethttps://portal.nccs.nasa.gov/GISS_modelE/modelE_input_data/GLMELT_4X5.OCN.nc >> >> wgethttps://portal.nccs.nasa.gov/GISS_modelE/modelE_input_data/GLMELT_144X90_gas.OCN.nc _______________________________________________ gdal-dev mailing list gdal-dev@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/gdal-dev