switch to cql2 (continuation of #236)

[bkanuka]

Continuation of #236

Still in draft...

[bkanuka]

@vincentsarago can you explain a little more about the approach to CRS ? I don't know if the following is true:

• Data can be in any CRS, this is specified in PostGIS and we we just ST_Transform to 4326 at query time
• OGC Features/GeoJSON responses are always in 4326
• bbox in the query params are always assumed to be 4326? (or are they assumed to be the source CRS?)
• Tiles can be requested and returned in any CRS but if not specified, then assume Web Mercator EPSG:3857

Could you clarify a bit? Thanks

[bkanuka]

Removed buildpg and building the WHERE with cql2-rs. Ready for someone else to get eyes on this!

This is kinda a big PR (sorry). Tests all pass.

[vincentsarago]

Hi @bkanuka
I'm trying to pick this up

Data can be in any CRS, this is specified in PostGIS and we we just ST_Transform to 4326 at query time

Yes,

tipg/tipg/collections.py

Lines 501 to 503 in 1d269b3

	# Reproject to WGS64 if needed
	if geometry_column.srid != 4326:
	g = logic.Func("ST_Transform", g, pg_funcs.cast(4326, "int"))

OGC Features/GeoJSON responses are always in 4326

Yes

bbox in the query params are always assumed to be 4326? (or are they assumed to be the source CRS?)

Yes, because we choose not to implement part 2 of the spec #35

Tiles can be requested and returned in any CRS but if not specified, then assume Web Mercator EPSG:3857

a TMS object must be passed to the get_tile method

tipg/tipg/collections.py

Lines 856 to 860 in 1d269b3

	async def get_tile(
	self,
	conn: asyncpg.Connection,
	*,
	tms: TileMatrixSet,

so there no default.

[bkanuka]

Great. That was my understanding, but reasoning about transformations is hard so there's a chance I fumbled it.

Side note: I'm not a fan of 1000+ line files but didn't want this pr to also include refactoring. Maybe that will come later 😉

[vincentsarago]

👍

[vincentsarago]

I'm not sure to see where we do the transformation from TMS's CRS to the Geometry column's CRS

[vincentsarago]

https://github.com/developmentseed/tipg/pull/236/changes#diff-db0c25ec9d8f23d512f69d229dda0d95ed543404e78e377430e5deebeefd8c41R432-R439

[vincentsarago]

@bkanuka could you explain? 🙏

[bkanuka]

tile_target_srid is the column CRS. So those lines are where the transformation is done. I added code comments that might clarify. (maybe I'm the one confused though!)

[vincentsarago]

@bkanuka This is excellent,

Thanks for all the docstrings, it really helped for the review 🙏

I just have one comment about the tile bbox reprojection, once we figure this we can merge 🙏

[bkanuka]

I will get back to everything here next week. Still top of mind to get this merged but human life is limiting my response time ATM.

[vincentsarago]

thanks a lot @bkanuka 🙏