jiayuasu opened a new issue, #1165:
URL: https://github.com/apache/sedona-db/issues/1165
Two boundary-only configurations produce wrong answers from the native
topology predicates. Both disagree with Shapely/GEOS and PostGIS, and both are
silent wrong rows rather than errors.
## 1. `ST_Touches` misses a line whose interior passes through a polygon
corner
```sql
SELECT
ST_Touches(
ST_GeomFromText('POLYGON ((0 0, 2 0, 2 2, 0 2, 0 0))'),
ST_GeomFromText('LINESTRING (1 3, 3 1)')) AS touches,
ST_Intersects(
ST_GeomFromText('POLYGON ((0 0, 2 0, 2 2, 0 2, 0 0))'),
ST_GeomFromText('LINESTRING (1 3, 3 1)')) AS intersects;
```
```
touches = false
intersects = true
```
The line passes through the polygon's corner `(2 2)` without entering the
interior — the intersection is the single boundary point, so `touches` should
be `true` (Shapely returns `true`). `ST_Intersects` correctly sees the
intersection, so the pair is classified as intersecting-but-not-touching, which
no DE-9IM class supports for this geometry pair.
Notably, a line whose *endpoint* meets the corner (`LINESTRING (2 2, 3 3)`)
is handled correctly — the failure is specific to the intersection point lying
in the line's interior.
## 2. `ST_Within` wrongly matches a line lying on a hole boundary
```sql
SELECT ST_Within(
ST_GeomFromText('LINESTRING (3 3, 3 7)'),
ST_GeomFromText('POLYGON ((0 0, 10 0, 10 10, 0 10, 0 0), (3 3, 7 3, 7 7, 3
7, 3 3))'));
-- true; Shapely and PostGIS: false
```
The line lies entirely on the boundary of the polygon's hole. `within`
requires the interiors to intersect (DE-9IM `T*F**F***`), and a line contained
in the boundary never intersects the interior, so the correct answer is `false`.
## Scope checked
These neighbouring configurations are all correct: line endpoint at a corner
(`touches`), line along an outer edge (`touches`), polygons sharing a corner
(`touches`), point at a corner (`touches`), point inside a hole, point on a
hole boundary, line across a hole, and polygon inside a hole
(`within`/`contains`/`covers`/`covered_by`). So the defects look like specific
gaps in boundary-interior classification rather than a broad relate problem.
## Impact
Both surface through spatial joins as silently missing or extra rows —
`sjoin(predicate="touches")` drops the crossing-corner pair, and
`sjoin(predicate="within")` fabricates a match for hole-boundary linework.
Found by GeoPandas-parity testing of `sedonadb-geopandas` (#1142);
documented there as known engine limitations pending this fix.
Version: `sedonadb` 0.5.0 (source build of current `main`).
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
