Intersection test error with curved polygons

[aaime]

As reported on the user list, I'm encountering a precision problem with an intersection test involving curve polygons.

Test data can be found in this Github Gist: ​https://gist.github.com/aaime/dcf55b635c5bd09c2b9ebb31a2ab083a

Test for intersection with a point returns two polygons, while only one polygon actually contains the point:

SELECT ogc_fid FROM testdata WHERE ST_Intersects(geom, ST_GeomFromText('POINT (25492818 6677399.98)', 3879));
 ogc_fid
---------
    1258
   12875
(2 rows)

The issue has been verified with:

• postgis 3.2 and postgresql 14.15
• postgis 3.5 and postgresql 17.2 (latest postgis docker image)

After discussion we found the issue is that the are linearized before the intersection test with GEOS, and that using a native curve operator like distance offers instead the correct result:

SELECT ogc_fid, ST_Distance(ST_GeomFromText('POINT (25492818 6677399.98)', 3879), geom) FROM testdata;

 ogc_fid |     st_distance    
---------+---------------------
    1258 | 0.01234572446598792
   12875 |                   0
(2 rows)

It looks like the issue could be addressed in a few ways:

• Native curve support for intersection (hard)
• For more practical applications, maybe allow control of the tolerance used in linearization? Someone knowing the accuracy of their data could set a variable declaring the desired precision