raster <-> vector processes

[jdries]

For an internal use case, we'd like to apply raster to vector conversion:

1. input is a raster datacube
2. output is a 'vector datacube' that can be exported as geojson

This is not uncommon, so we'd like to see if we can provide this as higher level process.
We will probably implement something internally first, to see how it can look like.

[m-mohr]

As soon as you have a process definition I'd suggest to open a draft PR so that we can shape it together.

[jdries]

Some inspiration for naming:

• GDAL has gdal_polygonize
• GEE has reduceToVector, and also has behaviour for the multiband case https://developers.google.com/earth-engine/reducers_reduce_to_vectors
• GRASS GIS has r.to.vect https://grass.osgeo.org/grass78/manuals/r.to.vect.html

[m-mohr]

Can we model this as reducer in openEO? If not, reduce would be a bit confusing, I think. polygonize only works if it's always working on polygons only. I think I'd prefer something easy to understand and aligned with other processes such as create_raster_cube like vector_cube, to_vector or convert_cube (if it also allows vector to raster at some point). I'm not set on anything yet. Question is also how we'd like to name vector to raster once it comes up?

[jdries]

Implemented a first prototype:
https://openeo.vito.be/openeo/1.0/processes/backend/raster_to_vector

[m-mohr]

@jdries We should complete the description and PR it for discussion.

[PondiB]

@jdries and @m-mohr, is this being worked on?

[m-mohr]

VITO has a custom implementation, but we still need to get a version into openeo-processes. @PondiB

[PondiB]

Cool, I will pick it up then.

[m-mohr]

Cool, please consider a survey of existing implementations, e.g. at VITO (already openEO), GRASSGIS, Python ecosystem (shapely?), R, ... @PondiB

[PondiB]

@m-mohr , Sure, I will do that.