Is there a need to standardize geom and geometry across ecosystem

[alex-s-gardner]

I'm finding geom and geometry used interchangeably but this creates some conflicts across package. It seems like some guidance might be needed:

Documenting some of what I've noticed:

@evetion uses geom in GeoDataFrames which then can not be passed directly to @rafaqz Raster.rasterize

@asinghvi17 also uses geom in GeometryOps

GeoInterface has a GeometryCollection but a function call that is getgeom

Shapefile creates a geometry column

[rafaqz]

We have GI.geometrycolumns to clarify these in many cases. GeometryOps should use it everywhere, we don't use :geom ? except in one tutorial because GADM.jl did.

:geometry is the standard fallback for GI.geometrycolumns

@evetion I noticed this the other day too, is there a reason to still use :geom in GeoDataFrames?

Also GADM.jl recently fixed their :geom column to :geometry: JuliaGeo/GADM.jl#69

[asinghvi17]

Using :geom for geometry columns started because that was how ArchGDAL returned it, I think. Users might expect it now though? I'm not sure how that should be handled.

[rafaqz]

We should as much as possible standardise table columns, it's worth the long term simplicity

[alex-s-gardner]

Understanding that GI.geometrycolumns is being implemented making this less of an issue:

e.g.
which one if I'm package blind?

GeometryOps.intersects.(geomA[:, :geometry], geomB[:, :geom])
GeometryOps.intersects.(geomA[:, :geo], geomB[:, :geometry])
GeometryOps.intersects.(geomA[:, :geometry], geomB[:, :geometry])
GeometryOps.intersects.(geomA[:, :geom], geomB[:, :geom])

or just

GeometryOps.intersects.(geomA[:, :geometry], geomB[:, :geometry])

[asinghvi17]

GeometryOps.intersects.(geomA[:, first(GI.geometrycolumns(geomA))], geomB[:, first(GI.geometrycolumns(geomB))]) is the "correct" solution at this point but it's a mouthful. If you aren't using GeoDataFrames/ArchGDAL at all for vector features, then :geometry is your best bet.

[rafaqz]

Yeah... good demonstratiion that first(GI.geometrycolumns(geomA)) is waay too long to actually use

[alex-s-gardner]

Reiterating that standardizing on the geometry column name (either "geometry" or "geom") early could provide long-term benefits. I find myself continually having to check if "geom" or "geometry"

[rafaqz]

Where is it still :geom? This is just GDAL?

There is not much more we can do here, GeoInterface has both a standard name (:geometry) and a function to get non standard names.

Probably an issue at the offending source is more actionable

[asinghvi17]

Any non-GeoJSON thing loaded by GDAL has :geom as a geometry column, this includes everything returned by GeoDataFrames. That's the primary problem here.

I had two proposals on GeoInterface to extend this so we can do GI.geometry(df) instead and have it just work, maybe we should discuss those in Jan (or earlier, if we want to move things faster?)

[alex-s-gardner]

OK, so is there a scenario where we rename GDAL "geom" columns to "geometry" for consistency, or is this bad practice?

I'm using GI.geometrycolumns, but it's pretty cumbersome and not easy for a new user to discover.

[rafaqz]

So there are two problems. GI.geometrycolums is cumbersome, and ArchGDAL is returning :geom.

An issue at ArchGDAL is the best place for the second problem.

The first is here, but I'm not sure how to fix that.

GI.geomcol(t) returning a single column is the shortest I can think of. But it really doesn't beat :geometry.

[evetion]

I have the same frustration, and it is an open discussion how to fix it. We went for the all should be compatible route, which now leads to some cumbersome code. I think the fixes are mostly in packages (those should use first(GI.geometrycolumns(thing)), not the user). And extending GI.geometry (now only defined for features) seems like a good plan.

[rafaqz]

GI.geometry(sometable) would be really nice.

But getting the column with other table syntax will also be something people try...
Is there a reason we cant also swap :geom to :geometry in ArchGDAL ?

[visr]

As I understand, geom doesn't come from GDAL.jl or ArchGDAL.jl, but is a default geometry column name used by some GDAL drivers. See e.g. https://gdal.org/en/latest/drivers/vector/gpkg.html

GEOMETRY_NAME=value: Defaults to geom.

So far GDAL.jl and ArchGDAL.jl just followed GDAL's lead here. Besides geom vs geometry is also remember `` (the empty string) being one of the names that pops up. It probably makes sense for GDAL.jl to keep doing this, ArchGDAL.jl could be a bit more opinionated on this.

[rafaqz]

Yes it would make a lot of sense for ArchGDAL to change both :geom and empty strings to :geometry

[rafaqz]

Ok I made an ArchGDAL issue