[gdal-dev] Incorrect geolocation information using newer gdal versions

[Andrew C Aitchison]

On Tue, 26 Mar 2024, Cristhian Rivera via gdal-dev wrote:

> Hi all,
>
> I'm trying to debug an issue with a NetCDF file where in previous gdal
> versions (up until 3.3.0) the geolocation was correctly identified by
> gdalinfo, but in newer versions (>= 3.3.1) it is not.

I note that both versions output the warnings:

Warning 1: dimension #2 (Easting) is not a Longitude/X dimension.
Warning 1: dimension #1 (Northing) is not a Latitude/Y dimension.

gdalinfo --debug on 20240321000000.nc
gives me more info:

Warning 1: dimension #2 (Easting) is not a Longitude/X dimension.
Warning 1: dimension #1 (Northing) is not a Latitude/Y dimension.
GDAL_netCDF:
=====
SetProjectionFromVar( 65536, 4)
GDAL_netCDF: got grid_mapping crs
GDAL_netCDF: bIsGdalFile=0 bIsGdalCfFile=0 bSwitchedXY=0 bBottomUp=1
netCDF: Georeferencing ignored due to non-specific enough X axis name. Set 
GDAL_NETCDF_IGNORE_XY_AXIS_NAME_CHECKS=YES as configuration option to 
bypass this check
netCDF: Georeferencing ignored due to non-specific enough Y axis name. Set 
GDAL_NETCDF_IGNORE_XY_AXIS_NAME_CHECKS=YES as configuration option to 
bypass this check
GDAL_netCDF: bGotGeogCS=0 bGotCfSRS=0 bGotCfGT=0 bGotCfWktSRS=0 
bGotGdalSRS=0 bGotGdalGT=0
GDAL_netCDF: did not get geotransform from CF nor GDAL!
GDAL_netCDF: did not get projection from CF nor GDAL!
GDAL_netCDF: netcdf type=5 gdal type=6 signedByte=1
GDAL: GDALOpen(20240321000000.nc, this=0x63c988f650a0) succeeds as netCDF.
GDAL: GDALDefaultOverviews::OverviewScan()
GDAL: GDALClose(20240321000000.nc, this=0x63c988f650a0)


> In the attachments are the outputs of gdalinfo from the versions mentioned,
> but the difference in both outputs is that newer versions cannot find the
> "Origin" and "Pixel size", and the Corner coordinates differ a lot:
>
> *Gdal 3.3.0:*
>
>> Origin = (24500.000000000000000,465500.000000000000000)
>> Pixel Size = (1000.000000000000000,-1000.000000000000000)
>
>
>
> Corner Coordinates:
>> Upper Left  (   24500.000,  465500.000)
>> Lower Left  (   24500.000,   14500.000)
>> Upper Right (  375500.000,  465500.000)
>> Lower Right (  375500.000,   14500.000)
>> Center      (  200000.000,  240000.000)
>
>
>> = *Gdal 3.3.1*
>
>> Corner Coordinates:
>> Upper Left  (    0.0,    0.0)
>> Lower Left  (    0.0,  451.0)
>> Upper Right (  351.0,    0.0)
>> Lower Right (  351.0,  451.0)
>> Center      (  175.5,  225.5)
>
>
> The files can also be found in the following drive repo if they are not
> available in the mail:
> https://drive.google.com/drive/folders/1zqV3n2SYUhOjgwxpYpChwqdNTiHAgNHj?usp=sharing
>
>
> I've tried checking the changelog of that version but it seems only like a
> bug fix release.
> Any ideas of what else I can test to identify the issue?


-- 
Andrew C. Aitchison                      Kendal, UK
                    andrew at aitchison.me.uk