#2 Result from difference overlaps, A.difference(B).overlaps(B)

open
nobody
None
5
2009-10-06
2009-10-06
Bertil Karlsson
No

When I take the difference from 2 geometries (AB) and try to check for overlap against what I used for difference, it is considered as an overlap (A.difference(B).overlaps(B))! This occures both in floating as well as in fixed precision model.

How am I supposed to 'clip' against geometries if this is not the way to do it?

This is also reproducable in the JTS Testbuilder so I must be doing something wrong here, but I can't find it.

Beginners mistake?

BRGDS

/B

Discussion

  • JUnit testcases

     
  • I should perhaps say that we are using 1.9, but I can reproduce the problem in 1.10 also!

     
  • Dr JTS
    Dr JTS
    2009-11-05

    This is probably due to precision issues. In general, the finite precision of JTS geometries means that the overlay operations and the spatial predicates are not completely consistent with each other.

    If you can post the test geometries I can validate this.

    Also, posting to the JTS mailing list given at http://tsusiatsoftware.net/jts is preferable