proj fields on band level?

[soxofaan]

Is it valid to have proj fields declared at "band" level?

e.g. this item https://stac.openeo.vito.be/collections/SWE_MERGED_V4.0/items/aa3efe9ba849a81e3da5417a1c82c20637b3a8b2 currently only has proj fields declared at bands level (nothing at item nor asset level yet):

{
  "type": "Feature",
  "stac_version": "1.1.0",
  ...
  "assets": {
    "enclosure_2": {
      "href": "https://data.cci.ceda.ac.uk/thredds/fileServer/esacci/snow/data/swe/MERGED/v4.0/1979/01/19790104-ESACCI-L3C_SNOW-SWE-SMMR_NIMBUS7-fv4.0.nc",
      "type": "application/x-netcdf",
      "title": "Download",
      "roles": [
        "data"
      ],
      "bands": [
        {
          "name": "swe",
          "description": "Snow Water Equivalent",
          "data_type": "float64",
          "nodata": -1.0,
          "proj:shape": [
            1800,
            3600
          ],
          "proj:bbox": [
            -179.999986,
            -89.999972,
            179.999986,
            89.999986
          ],
          "proj:code": 4326,
          "raster:spatial_resolution": 11116.4,
          "unit": "mm"
        },
        {
          "name": "swe_std",
          "description": "statistical standard deviation of estimate",
          "data_type": "float64",
          "nodata": -1.0,
          "proj:shape": [
            1800,
            3600
          ],
          "proj:bbox": [
            -179.999986,
            -89.999972,
            179.999986,
            89.999986
          ],
          "proj:code": 4326,
          "raster:spatial_resolution": 11116.4,
          "unit": "mm"
        }
      ],

related to

• load_stac: wrong crs for CCI STAC 1.1 collection Open-EO/openeo-geopyspark-driver#1391

[soxofaan]

not sure how relevant this is, but the STAC browser seems to detect proj:shape, proj:bbox and proj:code at this level:

[jdries]

the netCDF file format has the capability to use different coördinate systems for variables within the same asset.
In the example however, we could also consider to detect that proj metadata is indeed shared across assets.