Tuesday 22 August 2017

grass - What am I doing wrong with QGIS v.clean?



I thought I understood how the GRASS v.clean tool worked in QGIS (in 2.6.1 Brighton) but I keep getting unexpected results and errors with a polygon ShapeFile. I've run the QGIS TopologyChecker with the following rules over the file:



  • layer must not overlap

  • layer must not have gaps

  • layer must not have duplicates

  • layer must not contain invalid geometries


747 errors were found, all of the gap and overlap type. I tried using the v.clean snap tool to eliminate the overlaps but this happened:


original layer with processed polygons and error polygons overlayed close-up of v.clean issue


Can anyone point me in the right direction and/or point out what I'm doing wrong? The v.clean tool appears to be removing vertices and actually creating errors. All I want is the slivers in between polygons removed and the polygon holes filled in.



In the end I need a topological ShapeFile to generalize. I've found what I need for generalization here: Generalizing polygon file while maintaining topology in QGIS?




No comments:

Post a Comment

arcpy - Changing output name when exporting data driven pages to JPG?

Is there a way to save the output JPG, changing the output file name to the page name, instead of page number? I mean changing the script fo...