Add a vector dimension

[m-mohr]

A WIP draft for a new dimension of type vector.

[mkadunc]

The other question which representations we allow in metadata. Right now it supports:

• GeoJSON (full set right now, so includes Features, but we may want to remove FeatureCollections though, see above)
• WKT for Geometries
• IDs

Is it still a vector cube if it has IDs as labels of the vector dimension? For all uses in processes, such a cube would be just a normal data-cube; what use is calling such a dimension vector?

What is the benefit of supporting both GeoJSON and WKT? I'd go with just GeoJSON.

[m-mohr]

Is it still a vector cube if it has IDs as labels of the vector dimension?

Yes, the metadata just gives an overview of what is inside. It doesn't necessarily reflect the full internal structure.

For all uses in processes, such a cube would be just a normal data-cube; what use is calling such a dimension vector?

We are in STAC here, there are no processes involved here, but the difference is for example that you have an extent in x and y direction at the same time (see different fields in the dimension). And in general, it's just a tad different from the others and that's the same for all the other types exposed here. Each of them could basically also described as "Additional Dimension", but still we have some specifics here and there added so that it seems to make sense to distinguish them.

What is the benefit of supporting both GeoJSON and WKT? I'd go with just GeoJSON.

GeoJSON is WGS84 while in WKT you can give the coordinates in the reference system given for the dimension while on the other hand GeoJSON features could also include properties, which is not possible in WKT (afaik). So depending on the use case you may want to choose the best fit. In the end, I just wasn't sure what people (also outside of openEO as this is the STAC extension) would prefer.

[m-mohr]

Should we add a vector type field to indicate whether e.g. all geometries are points?

[mkadunc]

Should we add a vector type field to indicate whether e.g. all geometries are points?

yes

[m-mohr]

Added geometry_types and axes as new fields.

This is ready for final review!

[m-mohr]

@soxofaan @mkadunc @aljacob @clausmichele @jdries @dthiex @LukeWeidenwalker @pierocampa This is also ready for final review.

[aljacob]

As discussed yesterday, looks all good to me now, thanks for the hard work!!

[jdries]

nice work!