Backtracking why creating a GeoBox fails

[peanutfun]

It is often not clear to me why the computation of a GeoBox fails. In this case, arr.odc.geobox simply returns None, without any further explanation of what data is missing. From the code, I see that the GeoState requires either gcp or transform to be set. Retrieving those is done through rather complicated functions. It would be great if the user could back-track a bit better where things went wrong and what information in the dataset is missing.

In my case, I assigned a coordinate system to a reprojected data array:

>>> print(arr)
<xarray.DataArray (eps: 1, ref_time: 1, y: 1000, x: 1000)> Size: 8MB
array([[[[0.        , 0.        , 0.        , ..., 0.        ,
          0.        , 0.        ],
         [0.        , 0.        , 0.        , ..., 0.        ,
          0.        , 0.        ],
         [0.        , 0.        , 0.        , ..., 0.        ,
          0.        , 0.        ],
         ...,
         [0.00092668, 0.0008394 , 0.00075212, ..., 0.        ,
          0.        , 0.        ],
         [0.00095773, 0.00087046, 0.00078318, ..., 0.        ,
          0.        , 0.        ],
         [0.00098879, 0.00090151, 0.00081423, ..., 0.        ,
          0.        , 0.        ]]]])
Coordinates:
  * eps          (eps) int64 8B 0
  * ref_time     (ref_time) datetime64[ns] 8B 2025-11-28T06:00:00
    lead_time    timedelta64[ns] 8B 02:00:00
    valid_time   (ref_time) datetime64[ns] 8B 2025-11-28T08:00:00
    lon          (y, x) float64 8MB 5.95 5.955 5.959 5.964 ... 10.61 10.61 10.62
    lat          (y, x) float64 8MB 45.8 45.8 45.8 45.8 ... 47.81 47.81 47.81
    spatial_ref  int64 8B 0
Dimensions without coordinates: y, x
Attributes:
    metadata:     <earthkit.data.readers.grib.metadata.StandAloneGribMetadata...
    parameter:    {'centre': 'lssw', 'paramId': 500401, 'shortName': 'TOT_PRE...
    geography:    {'gridType': 'unstructured_grid', 'bitmapPresent': 0}
    vref:         geo
    vcoord_type:  surface
    origin_z:     0.0

and the GeoState looks like this:

print(arr.odc._state)
GeoState(spatial_dims=('y', 'x'), crs_coord=<xarray.DataArray 'spatial_ref' ()> Size: 8B
array(0)
Coordinates:
    lead_time    timedelta64[ns] 8B 02:00:00
    spatial_ref  int64 8B 0
Attributes: (12/18)
    crs_wkt:                            PROJCS["CH1903+ / LV95",GEOGCS["CH190...
    semi_major_axis:                    6377397.155
    semi_minor_axis:                    6356078.962818189
    inverse_flattening:                 299.1528128
    reference_ellipsoid_name:           Bessel 1841
    longitude_of_prime_meridian:        0.0
    ...                                 ...
    longitude_of_projection_origin:     7.43958333333333
    azimuth_of_central_line:            90.0
    scale_factor_at_projection_origin:  1.0
    false_easting:                      2600000.0
    false_northing:                     1200000.0
    spatial_ref:                        PROJCS["CH1903+ / LV95",GEOGCS["CH190..., transform=None, crs=CRS('PROJCS["CH1903+ / LV95",GEOGCS["CH1903+",DATUM["CH1903+",SPHEROID["Bessel 1841",6377397.155,299.1528128,AUTHORITY["EPSG","7004"]],AUTHORITY["EPSG","6150"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4150"]],PROJECTION["Hotine_Oblique_Mercator_Azimuth_Center"],PARAMETER["latitude_of_center",46.9524055555556],PARAMETER["longitude_of_center",7.43958333333333],PARAMETER["azimuth",90],PARAMETER["rectified_grid_angle",90],PARAMETER["scale_factor",1],PARAMETER["false_easting",2600000],PARAMETER["false_northing",1200000],UNIT["metre",1,AUTHORITY["EPSG","9001"]],AXIS["Easting",EAST],AXIS["Northing",NORTH],AUTHORITY["EPSG","2056"]]'), geobox=None, gcp=None)

Still,

>>> arr.odc.geobox
None

[peanutfun]

I found the issue in my particular case: There were no coordinates attached to dimensions x and y. But this is my exact point: There should be some information reported back when I want to query the GeoBox and it does not exist