ST_Touches using Minkowski sums

[stefanpetrea]

Could ​ST_Touches use Minkowski sums in order to perform fast overlap tests on geometries?

If CGAL ​provides functionality around this, would this allow for an implementation in PostGIS? Not sure if PostGIS has a direct dependency on CGAL.

[stefanpetrea]

Someone just told me that there's an ​ST_MinkowskiSum function too (on versions ≥ 2.1.0).

Apart from ST_Touches, this may also be applicable to ​ST_Overlaps.

[robe]

Only the SFCGAL portion of PostGIS has direct dependency on SFCGAL. So this would only be possible to do if

a) The user has PostGIS compiled with SFCGAL support

and

b) The user sets their backend to sfcgal instead of geos.

Then it would follow the pattern of other functions we have twith wo implementations of the function and the

These are listed with the light cube on this page.

​http://postgis.net/docs/manual-2.3/PostGIS_Special_Functions_Index.html#PostGIS_TypeFunctionMatrix

[robe]

Milestone renamed