Opened 12 years ago
Closed 12 years ago
#1775 closed defect (fixed)
False negative motion collision detection in ST_ChangeEdgeGeom
| Reported by: | strk | Owned by: | strk |
|---|---|---|---|
| Priority: | high | Milestone: | PostGIS 2.0.1 |
| Component: | topology | Version: | 2.0.x |
| Keywords: | Cc: |
Description
While playing with topology edge simplification I encountered a case in which ST_ChangeEdgeGeom allows to change an edge geometry from A to B but doesn't allow it to move back from B to A.
Looking at the movement visually I can see that the movement should never be allowed.
Attachments (1)
Change History (6)
by , 12 years ago
| Attachment: | collision.png added |
|---|
comment:1 by , 12 years ago
comment:2 by , 12 years ago
I confirm that the result of the bogus allowance is an invalid topology (wrong face linking).
comment:3 by , 12 years ago
| Summary: | Asymmetric undetected edge motion collision → False negative motion collision detection in ST_ChangeEdgeGeom |
|---|
comment:4 by , 12 years ago
Found the culprit: ST_SymDifference(EMPTY, POLY) returns EMPTY — filed #1776 for this. Once that one is fixed this one should also be. We'll want a testcase for this anyway.
comment:5 by , 12 years ago
| Resolution: | → fixed |
|---|---|
| Status: | new → closed |
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from orange to green is allowed, from green to orange it is not: ERROR: Edge motion collision at POINT(699288 6901218)
The collision point is correctly reported as the island you see near the bottom.