Add profile for STAC catalogs #55
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| ### Dataset organization | ||
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| 1. STAC collections will be mapped to openEO collections | ||
| 2. All STAC products in the same collection have the same set of 'bands', that are defined at collection level. This allows backends to look up the selected bands in a product. |
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I assume this means eo:bands in summaries?
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I was thinking more in terms of raster:bands, even though I didn't explicitly require that one yet. It's more about what we in openEO have in the standard 'bands' dimension.
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I see, makes sense.
We are currently discussing merging raster:bands and eo:bands anyway, so this might get a bit less messy in the future.
| ### Projection information | ||
| openEO backends require knowledge about the projection system, which should be provided at the collection level if it is the same for all products. | ||
| Collections with multiple projections, for instance based on UTM, can specify it at product level. | ||
| The [proj:epsg](https://github.com/stac-extensions/projection#item-properties-or-asset-fields) property is used to specify the projection. |
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From other implementation I know that they need two of proj:transform, proj:shape, proj:bbox - This is not required in Platform, right?
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it would actually be very helpful, but not a lot of catalogs have this info in the metadata.
| ### Product geometry | ||
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| The product geometry specifies the footprint of the data in the raster file. It may be used by the backend for spatial filtering, | ||
| so any pixel outside of the footprint may not be loaded by the backend. The geometry is provided in EPSG:4326, but may be interpreted in the |
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This is invalid in STAC and contradicts with the "if this is perceived to be the case, the STAC specification should get precedence". The geometry must always be EPSG:4326, but you could provide a geometry and bbox in the native projection via proj:geometry and proj:bbox.
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But the geometry does specify the footprint in EPSG:4326 right? Or is the part about the interpretation wrong?
Maybe I should add that proj:geometry can be used as way to provide a less ambiguous geometry?
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Yes, the geometry must be EPSG:4326. proj:geometry can be used to specify a geometry in the native CRS (bbox works the same way). What I'm confused about is "but may be interpreted in the product projection system." - What does this mean/imply? I guess this should be dropped and replaced with a mention or the proj: fields?
Co-authored-by: Matthias Mohr <[email protected]>
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| This document lists the requirements for a data provider that wants to make a dataset available as a | ||
| new collection in the openEO platform. More specifically, it defines the requirements for STAC catalogs. The STAC specification | ||
| is also used within openEO, and is a common choice in the EO community. |
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| 1. STAC collections will be mapped to openEO collections | ||
| 2. All STAC products in the same collection have the same set of 'bands', that are defined at collection level. This allows backends to look up the selected bands in a product. | ||
| 3. Assets in a product are raster files that contain a single band. |
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This is not clear to me. What is meant by product? A single item? If that is stored as GTIFF it can contain also several bands.
| These are some often used examples: | ||
| - [eo:cloud_cover](https://github.com/stac-extensions/eo#eocloud_cover) for cloud cover percentage | ||
| - [sat:orbit_state](https://github.com/stac-extensions/sat#satorbit_state) for orbit direction (ascending/descending) | ||
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I think it would make sense to add/link to the things we already collected here: https://github.com/Open-EO/openeo-stac-extensions
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| 2. S3 authentication headers | ||
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| ## STAC metadata | ||
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Another useful extension would be the raster one, specifically when working with data that needs to be have rescale and offset applied https://github.com/stac-extensions/raster#raster-band-object.
In particular, this is essential for Senitnel-2 L2A to BOA conversion, as specified here: https://sentinels.copernicus.eu/web/sentinel/technical-guides/sentinel-2-msi/level-2a-algorithms-products
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