RelateOp fails for disjoint inputs with GeometryCollection

[dr-jts]

The relate operation fails when the inputs are disjoint and one input is a GeometryCollection:

bin/geosop -a "POINT(0 0)" -b "GEOMETRYCOLLECTION(POINT (1 1), LINESTRING (1 1, 2 2))" relate

Run-time exception: IllegalArgumentException: Operation not supported by GeometryCollection

Analysis

This occurs because GeometryCollection currently does not support the getBoundary method. This is because support for GeometryCollections as input to spatial predicates is a work-in-progress (e.g. see discussion on #982). Evaluating the IntersectionMatrix in a disjoint case requires computing the dimension of the boundary. This is currently implemented in a way which requires determining the boundary of the geometry (see BoundaryOp.hasBoundary), which fails for GeometryCollections.

The fix is probably to support determining the boundary dimension without materializing the actual boundary of the geometry. Note that if the "GC-Union-topology"semantic is to be used, determining the boundary dimension of a heterogeneous GeometryCollection requires handling special cases including:

• LineStrings forming rings
• LineString endpoint lying inside a Polygon