[GIS] Remove Duplicate Polygons Using Open Source Tools

open-source-gistopology

I have a shapefile containing features with duplicate geometries, but different attributes (e.g. a polygon with attribute XX, and an identical polygon with attribute XY). I want to identify the duplicates, then pick the one with the correct attributes, deleting the other.

I've tried topology tools in OpenJump/Kosmo, but without success. They have a 'delete duplicates' tool that does what I want, except seems to arbitrarily delete one of the features rather than letting me pick which one to keep.

I have access to QGIS, OpenJUMP, Kosmo, etc. and am able to install other open source/free tools if required.

Thoughts?

Best Answer

Besides PostGIS, you could also use a topological open source GIS (GRASS):

  1. Download and install
  2. Start and select the Location manager, use the tool to generate a new project database from your SHAPE file (called "GRASS Location"), see here for a step-by-step guide
  3. Import the SHAPE file
  4. Use the "v.clean" tool which offers a series of options
  5. Export map back to SHAPE file format with "v.out.ogr"

Sidenote: we are planning to offer a WPS for this so that you can polish your data via our Web portal.

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