Opened 2 months ago

Last modified 4 weeks ago

#5726 closed defect

Cases where ST_Overlaps(ST_Difference(a,b),b) = TRUE — at Initial Version

Reported by: dannytoone Owned by: pramsey
Priority: medium Milestone: PostGIS 3.4.3
Component: postgis Version: 3.4.x
Keywords: Cc:

Description 

POSTGIS="3.4.1 ca035b9" [EXTENSION] PGSQL="160" GEOS="3.12.1-CAPI-1.18.1" PROJ="9.2.1 NETWORK_ENABLED=OFF URL_ENDPOINT=https://cdn.proj.org USER_WRITABLE_DIRECTORY=/Users/DToone2/Library/Application Support/proj DATABASE_PATH=/Applications/Postgres.app/Contents/Versions/16/share/proj/proj.db" LIBXML="2.11.7" LIBJSON="0.17" LIBPROTOBUF="1.4.1" WAGYU="0.5.0 (Internal)"

I'm having a tough time thinking through the relational geometry of this, and I can't help but think this is a bug. If b is cut out from a, then the result should intersect with b along the shared boundary, but it shouldn't overlap. A resulting overlap would indicate that the ST_Difference was not complete. I've recently found several cases where ST_Overlaps(ST_Difference(a,b),b) = TRUE, and I thought I'd file a bug report to make sure.

Change History (1)

by dannytoone, 2 months ago

Attachment: incomplete_difference_overlaps.sql​ added

pg_dump of table with 25 rows that meet bug conditiojn

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