Bug report #2089
Buffer produces incorrect results with multipart vectors
|Affected QGIS version:||Regression?:||No|
|Operating System:||All||Easy fix?:||No|
|Pull Request or Patch supplied:||Resolution:||invalid|
|Crashes QGIS or corrupts data:||Copied to github as #:||12149|
1. create a new project in QGIS,
2. add layer kirdem2.epg4326.shp using Layers -> Add vector layer...,
3. Tools -> Geoprocessing tools -> Buffer(s), set buffer distance to -0.0003, choose output file, click OK
Expected result: an inner buffer of the polygons in platte carree distance (not real distance, as interpreting degrees as meters would be ambiguous)
Actual result: certainly not a buffer neither in platte carree distance nor in real geodetic distance nor any other projection. In some places, the buffer exceeds the original polygon border (see qgis_buffer_bug1.png); in some places, the buffer has "pixel artifacts" (qgis_buffer_bug1.png); some islands are missing altogether (qgis_buffer_bug2.png).
The input data kirdem2.epg4326.shp is part of the publicly available dataset '01.09.2009a. asustusüksus SHP' (zip - 13,65 MB, 6.11.2009 ) on
(I cut a small part out and converted to EPSG:4326 using QGIS).
#3 Updated by cfarmer - almost 10 years ago
- Resolution set to invalid
- Status changed from Open to Closed
Tested using f13d3f35 (SVN r14368).
I am unable to reproduce this error. Looking at the areas described in this ticket, results appear to be as expected. I suspect this was a GEOS error, but appears to now have been fixed (GEOS version?). Please test and confirm if this now works.
I am going to close this as "invalid" because this is now a relatively old ticket, and appears to now be invalid, however, if it is still a problem, please reopen this ticket.