Bug #104823 ST_Overlaps, ST_Touches returning different values in between SRID 0 and 4326

• Submitted: 3 Sep 2021 17:49
• Modified: 6 Sep 2021 8:50
• Reporter: Matt Miller
• Status: Verified
• Category: MySQL Server: GIS
• Severity: S3 (Non-critical)
• Version: 8.0.13, 8.0.23, 8.0.26
• OS: Any
• CPU Architecture: Any
• Tags: gis, overlaps, srid, st_overlaps, ST_Touches, touches

[3 Sep 2021 17:49] Matt Miller

Description:
Using polygons in the shape of the 8th, 11th and 14th Legislative Districts of Idaho, I saw inconsistent results when calling ST_Overlaps and ST_Touches on the shapes.  These three districts all touch, but do not overlap. When using an SRID of 4326, ST_Overlap returned 1 for each pair of districts and ST_Touches returned 0.  An SRID of 0 yielded reversed results.

Trying the same thing on a 3rd party program, I got the expected results (the three polygons touch one another, but do not overlap in both SRID 4326 and 0).

How to repeat:
I'll be attaching a .sql file, it's too long for this section.

[3 Sep 2021 17:51] Matt Miller

ST_Overlap/ST_Touches results

Attachment: idaho district sample.sql (application/octet-stream, text), 879.83 KiB.

[6 Sep 2021 8:50] MySQL Verification Team

Hello Matt Miller,

Thank you for the report and test case.

regards,
Umesh