GEOSDistance raises floating point exceptions for boundable geometries

[Brendan Ward]

GEOSDistance C API function (and likely underlying C++ implementation) is causing floating point overflow exceptions to be raised for certain distances for boundable geometries but not for points.

Test case demonstrating this: ​https://github.com/libgeos/geos/pull/485

This was encountered in pygeos: ​https://github.com/pygeos/pygeos/issues/404

For example, calculating the distance between 2 points does not set floating point exceptions, whereas calculating the distance between 2 lines or polygons that are the same distance apart does raise these exceptions.

[robe]

Retargeting in prep for GEOS 3.10.0 release

[caspervdw]

This specific issue has been solved in ​https://github.com/libgeos/geos/pull/485

However there are some situations remaining where a FP “invalid” flag is set:

• binary predicates on empty geometries
• voronoi_polygons on a point
• hausdorff_distance sets an invalid flag (in our seemingly normal test)
• offset_curve on an empty linestring

All through the CAPI. See pygeos ​https://github.com/pygeos/pygeos/pull/441 for the specific tests where I encountered the FP “invalid” flags.

[jorisvandenbossche]

It might be worth opening a github issue now (​https://github.com/libgeos/geos/issues) to keep track of this

[caspervdw]

Done ​https://github.com/libgeos/geos/issues/515