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stac-extensions / raster

Describes raster assets at band level (one or multiple) with specific information such as data type, unit, number of bits used, nodata.
Apache License 2.0
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Collection-level raster details #26

Closed m-mohr closed 1 year ago

m-mohr commented 2 years ago

We need to provide collection-level raster details for our data cubes.

Could we also allow something like:

{
  "id": "TERRASCOPE_S2_NDVI_V2",
  "title": "Sentinel-2 NDVI last 2 years over Europe + selected areas, by Terrascope.",
  "summaries": {
    "raster:bands": [
      {
        "name": "NDVI_10M",
        "nodata": 255,
        "data_type": "uint8",
        "statistics": {"minimum": 0, "maximum: "254"}
      },
      {
        "name": "SCENECLASSIFICATION_20M",
        ...
      }
    ],
    "instruments": [
      "MSI"
    ],
    "platform": [
      "SENTINEL-2"
    ]
  },
  ...
}
emmanuelmathot commented 2 years ago

I see no problem with such an enhancement

kylebarron commented 2 years ago

Is there a difference between item_assets and summaries here? Should raster:bands be in one place or the other or is there a case when they'd need to be in both?

m-mohr commented 2 years ago

As we don't have items, we put all collection metadata in summaries. In normal use cases you'd put them in item_assets, indeed.

jdries commented 1 year ago

I just finally discovered what item_assets is for. I'm actually wondering if that is perhaps a better option for this rather than trying to use summaries? We indeed have collections without items, so that is maybe weird, but other than that, this seems to be the standardized approach to documenting metadata about things that are tied to assets, like bands? If using the summaries options, would anyone outside of an openEO context really understand our metadata?

m-mohr commented 1 year ago

@jdries Right now summarizing eo:bands in summaries is fine, I think. The main issue is that raster:bands is just defined on the asset level, but then we also go forward with https://github.com/radiantearth/stac-spec/discussions/1213 and there the question also occurs: What should it apply to? What's actually the meaning of bands outside of assets?

The issue with item assets is that there is no asset for (collection-less) data cubes and defining one with an arbitrary key seems less understandable than having them in summaries.

matthewhanson commented 1 year ago

Discussed at STAC sprint.

Will be resolved in https://github.com/radiantearth/stac-spec/pull/1254