Opened 15 years ago
Closed 14 years ago
#1758 closed bug (worksforme)
Tools (Ftools): clip and difference tools give the same results
| Reported by: | lutra | Owned by: | cfarmer |
|---|---|---|---|
| Priority: | minor: annoyance | Milestone: | Version 1.2.0 |
| Component: | Python plugins and bindings | Version: | Trunk |
| Keywords: | Cc: | pcav, cfarmer | |
| Must Fix for Release: | Yes | Platform: | All |
| Platform Version: | Awaiting user input: | no |
Description
a) pick a layer
b) pick a grid that overlaps the above layer
c) do a "clip" operation with ftools using the grid as "clip layer"
d) do a "intersect" operation with ftools using the grid as "clip layer"
e) compare the results, seems to me identical
Should the "Clip Tool "use just the borders of the "clip layer"?.
Here you can download the shapesfiles (epsg 20790) I used/resulted in my test (qgis 1.2 rev. 11023, Ubuntu 9.04). "Inso" is the base layer, the rest are pretty self-explanatory.
Attachments (1)
Change History (11)
comment:1 by , 15 years ago
| Component: | C++ Plugins → Python plugins and bindings |
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follow-up: 4 comment:2 by , 15 years ago
| Resolution: | → fixed |
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| Status: | new → closed |
comment:3 by , 15 years ago
| Cc: | added |
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follow-ups: 5 7 comment:4 by , 15 years ago
Replying to cfarmer:
Note: In some cases geometries may still be mis-formed. This is a separate issue, and > will be addressed soon.
See attached image. Is this one of this cases?
by , 15 years ago
| Attachment: | Screenshot-1.png added |
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comment:5 by , 15 years ago
Replying to lutra:
See attached image. Is this one of this cases?
Yes. This appears to be an issue with the type of geometries that GEOS is returning. I have tried to eliminate these spurious geometries, but as you can see there is still some cleaning up to do...
-Carson
comment:6 by , 15 years ago
I don't know if it is important, but have you noticed that with Intersect this doesn't happens?
follow-up: 8 comment:7 by , 15 years ago
Replying to lutra:
See attached image. Is this one of this cases?
This should now be behaving properly in r11348. I have changed the underlying logic, so this tools should be slightly faster, and work better with large, complex datasets.
The test dataset provided with this ticket now works properly (as far as I can tell), however, please test and reopen this ticket if problem(s) persists.
-Carson
comment:8 by , 15 years ago
| Platform: | Debian → All |
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Replying to cfarmer:
The test dataset provided with this ticket now works properly (as far as I can tell), however, please test and reopen this ticket if problem(s) persists.
Seems to work fine!
Thanks a lot,
-- Giovanni --
comment:9 by , 15 years ago
| Priority: | major: does not work as expected → minor: annoyance |
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| Resolution: | fixed |
| Status: | closed → reopened |
Now clip and difference seem to give the same result
comment:10 by , 14 years ago
| Resolution: | → worksforme |
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| Status: | reopened → closed |
| Summary: | Tools (Ftools): clip and intersect tools give the same results → Tools (Ftools): clip and difference tools give the same results |
Hi Paolo, I made a few tests and seems to me that clip and difference are giving the right results. Feel free to reopen if is the case.
Should now be fixed in r11339. Please test and reopen ticket if not fixed properly. Note: In some cases geometries may still be mis-formed. This is a separate issue, and will be addressed soon.