Take the 2-minute tour ×
Geographic Information Systems Stack Exchange is a question and answer site for cartographers, geographers and GIS professionals. It's 100% free, no registration required.

I have a large polygone file with landuse information (6 classes). Its vectorised from a raster classification so the polygons are all angular. Any of my tries to generalize with v.generalize (sneaks, chaiken, douglas...) ends after minutes of working in a programm crash (GRASS and Qgis using sextante).

enter image description here

How can I smooth the edges of my polygons? Thanks!

share|improve this question
1  
How large are we talking? –  underdark Nov 29 '12 at 20:21
    
10.000 polygons. the shapefile is 12MB. –  MAP Nov 29 '12 at 20:58
2  
try convert your polygons to lines first then run the tool on lines - rebuild polygons afterwards. –  Mapperz Nov 29 '12 at 21:22
1  
If you still have the raster, then the GRASS module r.to.vect has an option "-s" to smooth the corners when creating vector polygons from raster areas. –  Micha Dec 1 '12 at 15:14
    
the smooth corners fuction just replaces a vertical + horizontally line by one diagonal line so its not getting realy smooth. –  MAP Dec 4 '12 at 19:10
show 3 more comments

1 Answer

In GRASS 7 the processing of massive vector data has been implemented. While not yet officially released, you can download weekly binary snapshots (source code as well of course) from:

http://grass.osgeo.org/download/

and tell Sextante in QGIS to use this installation instead of the existing one.

You can install GRASS 7 in parallel to GRASS 6, it will not interfere.

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.