Turf: Boolean Overlap - doesn't overlap inside polygon

[DenisCarriere]

@turf/boolean-overlap - doesn't overlap inside polygon

@rowanwins I've been using @turf/boolean-overlap to apply a mask operation on the grid modules. Each grid polygon does the boolean-overlap method and should return false/true, however it seems like the polygon that are completely within (not touching the lines) are not counted as overlapping, is that the expected behavior? I would assume that the inner polys should still be overlapping the mask polygon.

@stebogit Thoughts? Since we're working on the grid modules.

@turf/triangle-grid

@turf/square-grid

[stebogit]

@DenisCarriere from the docs @turf-overlaps

Compares two geometries of the same dimension and returns true if their intersection set results in _a geometry different from both_ but of the same dimension. It applies to Polygon/Polygon, LineString/LineString, Multipoint/Multipoint, MultiLineString/MultiLineString and MultiPolygon/MultiPolygon.

The intersection of the big polygon with the inner grid polygons is actually equal to the grid polygon, so they do not technically overlap (based on the definition).
I think here @turf/boolean-contains or @turf/boolean-within would be the appropriate one to use.

[rowanwins]

Hi @DenisCarriere

This definition from the FME docs is also helpful here

The interiors intersect, but neither feature is contained by the other, nor are the features equal.

So I think @stebogit is on the money with his recommendation, it might be worth a quick check to see if one or the other is more performant that than the other for this use case...

[DenisCarriere]

👍 Thanks for the answers, the FME docs are pretty good at explaining it, i'll use @turf/boolean-contains for what I'm trying to do.

The interiors intersect, but neither feature is contained by the other, nor are the features equal.

[DenisCarriere]

I actually combined both contains + overlap to get the final result:

Only using contains gave me this:

[stebogit]

I think contains + overlap is more similar to what you would expect out of this module. Good job! 👍

[rowanwins]

@DenisCarriere boolean-intersect is probably what is required to get the proper result

[DenisCarriere]

@rowanwins Agreed, however it's not implemented yet (the boolean-intersect) 😄

[DenisCarriere]

I'm using @turf/intersect and it works out pretty good for this scenario.