REGR: overlay keep_geom_type issue with collections of different types

[martinfleis]

Fixes #2176

I still need to fabricate some tests, this is a very edge case.

[jorisvandenbossche]

I still need to fabricate some tests, this is a very edge case.

You can start from the existing test_keep_geom_type_geometry_collection2 I wrote:

polys1 = [
    box(0, 0, 1, 1),
    box(1, 1, 3, 3).union(box(1, 3, 5, 5)),
]

polys2 = [
    box(0, 0, 1, 1),
    box(3, 1, 4, 2).union(box(4, 1, 5, 4)),
]
df1 = GeoDataFrame({"left": [0, 1], "geometry": polys1})
df2 = GeoDataFrame({"right": [0, 1], "geometry": polys2})

this gives

ax = df1.plot()
df2.plot(ax=ax, color="red", alpha=0.5)

So should be relatively straightforward to adapt the box so it only touches but not overlaps?

[jorisvandenbossche]

Ah, not, because if there is no overlap, the intersection also doesn't give the touching border ...

[jorisvandenbossche]

Touching point instead of touching linestring (border) seems to do it:

polys1 = [
    box(0, 0, 1, 1),
    box(1, 1, 3, 3).union(box(1, 3, 5, 5)),
]

polys2 = [
    box(0, 0, 1, 1),
    box(3, 1, 5, 2).union(box(5, 1, 6, 3)),
]
df1 = GeoDataFrame({"left": [0, 1], "geometry": polys1})
df2 = GeoDataFrame({"right": [0, 1], "geometry": polys2})

and then geopandas.overlay(df1, df2, keep_geom_type=True) triggers the error.

[martinfleis]

Ahh, I guess that while pygeos doesn't mind dissolving an array of None, shapely does...