[gdal-dev] Changes to NetCDF driver between 3.2 and 3.4 ?

[Alan Snow]

Hi Micha,

I answered the question on stackex change. Essentially, you have to provide
the CF axis metadata now. This can be addressed in rioxarray using
rio.write_coordinate_system.

Hopefully this is helpful,
Alan

On Fri, Oct 7, 2022, 7:04 AM Micha Silver <tsvibar at gmail.com> wrote:

> Hello:
>
> I'm using xarray and rioxarray in python to create a DataSet then export
> to Netcdf. After saving, when I check the exported files with gdalinfo
> using GDAL 3.2, I see the correct extent. However, when using GDAL >=3.4
> (i.e in a conda env) it seems that the extents are lost, and the NetCDF
> dimensions appear instead. This causes the resulting NetCDF to appear at
> coords (0,0) - the wrong place - in QGIS (on a system with the newer GDAL).
>
>
> Here is the output with my system installed GDAL:
>
>
> micha at RMS:Kinneret$ gdalinfo --version
> GDAL 3.2.2, released 2021/03/05
> micha at RMS:Kinneret$ gdalinfo  NETCDF:"Kinneret_velocity.nc":v | grep -A 4
> Corner
> Warning 1: dimension #2 (x) is not a Longitude/X dimension.
> Warning 1: dimension #1 (y) is not a Latitude/Y dimension.
> Warning 1: dimension #0 (z) is not a Time or Vertical dimension.
> Corner Coordinates:
> Upper Left  (  735758.000, 3644806.000) ( 35d31'15.70"E, 32d54'57.98"N)
> Lower Left  (  735758.000, 3621606.000) ( 35d30'54.46"E, 32d42'25.30"N)
> Upper Right (  754558.000, 3644806.000) ( 35d43'18.74"E, 32d54'42.80"N)
>
> Lower Right (  754558.000, 3621606.000) ( 35d42'55.82"E, 32d42'10.25"N)
>
>
> However, in my conda environment, with a newer GDAL:
>
>
> micha at RMS:Kinneret$ conda activate geo
> (geo) micha at RMS:Kinneret$ gdalinfo --version
> GDAL 3.5.2, released 2022/09/02
> (geo) micha at RMS:Kinneret$ gdalinfo  NETCDF:"Kinneret_velocity.nc":v |
> grep -A 4 Corner
> Warning 1: dimension #2 (x) is not a Longitude/X dimension.
> Warning 1: dimension #1 (y) is not a Latitude/Y dimension.
> Warning 1: dimension #0 (z) is not a Time or Vertical dimension.
> Corner Coordinates:
> Upper Left  (    0.0,    0.0)
> Lower Left  (    0.0,   58.0)
> Upper Right (   47.0,    0.0)
> Lower Right (   47.0,   58.0)
>
> What do I need to add to the xarray Dataset so that the newer GDAL gets
> the correct extent?
>
> In both cases all the "grid_mapping" metadata entries point to
> "spatial_ref", and the full spatial_ref details are available in the NetCDF
> file.
>
>
> (Note: double posted to GIS.stackexchange at
> https://gis.stackexchange.com/questions/442323/changes-to-gdal-netcdf-driver-between-3-2-and-3-4
> )
>
>
> Thanks
>
> --
> Micha Silver
> Ben Gurion Univ.
> Sde Boker, Remote Sensing Lab
> cell: +972-523-665918
>
> _______________________________________________
> gdal-dev mailing list
> gdal-dev at lists.osgeo.org
> https://lists.osgeo.org/mailman/listinfo/gdal-dev
>
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