Bug #69425 St_Intersection produces incorrect results

• Submitted: 7 Jun 2013 12:43
• Modified: 21 May 2015 14:34
• Reporter: Ivan Balashov
• Status: Closed
• Category: MySQL Server: GIS
• Severity: S2 (Serious)
• Version: 5.6.11, 5.6.21
• OS: FreeBSD (from ports)
• CPU Architecture: Any
• Tags: 5.6, spatial, St_Intersection

[7 Jun 2013 12:43] Ivan Balashov

Description:
St_Intersection produces incorrect results while calling several times on multipolygon with holes and polygon intersection.

St_Intersection makes as result an multipolygon with incorrect holes.

St_Intersection makes different intersection results on multiply calls.

Single call gives right result.

To detect this bug you may calculate Area(St_Intersection) or view on resulting geometry in geometry viewers. Area fluctuation in how-to-repeat query is shown.

How to repeat:
Execute queries from attached file.
See at ST_AREA column values - it varies from 0.005072965010581285 to 0.0076609711081375015

[7 Jun 2013 12:43] Ivan Balashov

test queries

Attachment: St_Intersection_bug.sql (text\plain, text), 36.84 KiB.

[21 Jul 2014 19:30] Sveta Smirnova

Thank you for the report.

Verified as described.

[21 May 2015 14:34] Paul DuBois

Noted in 5.7.8, 5.8.0 changelogs.

Multiple calls to ST_Intersection() could return inconsistent results
for some arguments.

[21 May 2015 14:44] Paul DuBois

Issues were resolved by use of Boost.Geometry for GIS algorithms.