Simplify Geometries Preserving Topology

Simplify Geometries Preserving Topology

Simplifies the geometry of polygons and lines preserving topology. Spatial relations are unaffected after the simplification. Polygons are simplified without creating slivers (overlaps or gaps). Allows to export to various vector formats.


This tool allows to simplify highly detailed geodata (polylines/polygons - eg. census boundary data) with respect to the topology of neighbors. When you're intending to create for example only overview maps, such high accuracy is not needed. Generalization during the simplification process preserves the geometry relationship (topology) - so there are no overlaps or gaps.

Too much detail in the geometries can slow down the data rendering and response of your application. Simplification also significantly reduces the file size. To reduce the file size even more, the tool allows export to various vector formats - including TopoJSON, GeoJSON, ESRI Shapefile, etc.

Keywords: simplify, generalization, topology, polygons, lines


  • Input vector data - Requires vector data containing lines or polygons
  • Complexity of the geometry - Simplifies to a given percentage of original number of points defining individual geometry. For example 20% means that 80% of points will be removed.
  • Reduce the number of decimal places - Round coordinates to specified number of places.
  • Number of decimal places - Round precision of coordinates for vertices of all features to specific number of decimal places. For data in degrees the default precision of 5 decimal places roughly equals of precision of about 1.1 m.
  • Output format - File format of output data
  • Output coordinate system - Choose what coordinate system the output data (regular grid) should be in.


Simplified vector data (polygon/polyline) in selected output file format.


  • 2020-11-20 20:46 - The tool has been created.

Simplify Geometries Preserving Topology