Simplification of multi-geometries

[skygering]

Currently, when GeometryOps simplifies multi-geometries, it just simplifies each sub-geometry and then reconstructs. However, LibGEOS suggests that entire sub-geometries can be removed. See the example below:

import GeoInterface as GI
import GeometryOps as GO
import LibGEOS as LG

mp_coords = [
    [[[24332.448443033114, 78156.5044920507], [24335.48046004802, 78155.02337099149], [24332.100142171057, 78154.15319217058], [24332.448443033114, 78156.5044920507]]],
    [[[24721.947085257176, 80785.92121346148], [32813.95278360643, 88654.68891218181], [34573.68704928234, 87616.90783669954], [33538.70270722534, 80524.1641959386], [24414.252883053858, 78175.30137343572], [24333.793108370985, 78165.5820218308], [24721.947085257176, 80785.92121346148]]],
]

lg_vals = GI.coordinates(LG.simplify(mp, 100.0))
go_vals= GI.coordinates(GO.simplify(mp; tol = 100.0))

lg_vals is the coordiantes of a polygon, while go_vals is a multipolygon.

[rafaqz]

That wont be type stable... we can remove rings but it should always come out a MultiPolygon if it went in a MultiPolygon

[skygering]

Yeah but should it now be a 1-element multi-polygon? I honestly think it is kind of weird to just delete a whole polygon. simplify is supposed to decrease the number of points, not make a "judgment call" about the polygon size. If we both agree on that then I will close this issue.

[rafaqz]

Yeah exactly, removing polygons us a totally different thing to removing points and should be a different function.