add support for predefinedtilegrid in split_area #883

[VincentVerelst]

The idea is to expose the split_area function to users. Users can provide an AOI, which can be split in different ways:

• By providing a projection and tile_size: splits the AOI up in square tiles
• By providing a PredefinedTileGrid (can also be a geopandas.GeoDataFrame), which splits the AOI according to that grid
• By providing a custom subclass of TileGridInterface: splits the AOI according to their custom class

The function returns the split AOI as a geopandas.GeoDataFrame

[HansVRP]

Some initial comments and questions

[HansVRP]

Do we need to rely on python 3.8 compatibility?

[VincentVerelst]

#717

It's needed for as long as the backend supports it

[HansVRP]

I am probably overlooking something; but this runs only client side?

or is the limitation due to the geometry we send into the back-end

[HansVRP]

do we have test coverage on the behavior if the AOI is a line or a single point?

[VincentVerelst]

Yes the TileGrid tests covered this case. Also added a test for split_area. Current behaviour: only dict, Polygon or MultiPolygon is allowed

[HansVRP]

perfect

[HansVRP]

if the dict contains for instance a line or point

the error will come when openEO tries to run it I assume?

[VincentVerelst]

No the job splitter will fail, because the bbox is validated to must have east>west and north>south

[HansVRP]

There still might be some niche cases we will encounter:

• e.g. inputs in a geographic CRS with coordinates that extend past ±180° longitude, this breaks the assumption that west < east
• Predefined tiles in a geographic CRS that wrap past the antimeridian

Couple of things we could do as follow up:

if west>east --> spliting two polygons and further split those seperatly. This seems low effort to me.

input polygons with lon past +-180 will be harder; I believe @soxofaan was also looking into this for the python client.

[HansVRP]

(made a small commit which I believe handles this: 1e0c178)

[VincentVerelst]

@HansVRP , except for addressing your comments, one big change: there is now a standardized reprojecting happening to the CRS of the tile grid that is being used for splitting.

To re-iterate what will be exposes to the public API: the split_area function now takes as input an AOI, which can be split in either of two ways:

• By providing a tile-grid as geopandas.GeoDataFrame or a list of (Multi)Polygon. In the background _PredefinedTileGrid will be used for splitting
• By providing a projection and tile_size. In the background _SizeBasedTileGrid will be used for splitting. The origin will be taken to be the bottom-left of the AOI provided by the user.

Advanced users can always define their own splitting method by defining a subclass of _TileGridInterface, which is still experimental and prone to change

[HansVRP]

will look into the update; thanks.

can you also include a usecase example in: https://github.com/Open-EO/openeo-python-client/blob/master/docs/cookbook/job_manager.rst ?