I have a polygon layer representing road surfacing layers. My task was to "thin out" the polygons in order to come up with a network of 'road centerlines' (dark green).

I generated this new polyline layer as follows in ArcMap:

  • Rasterized the road surfacing layer to a generously high resolution
  • Binarized the road surfacing layer where values of 1 indicate presence of road and values of 0 indicate no presence of road.
  • Thinned out the raster layer
  • Vectorized the thinned raster layer using "Raster to Polyline" tool

The result is conceptually OK since it does somehow find the centerlines of the polygons. However I am ending up with some really ugly artifacts as follows which originate from the thinned raster:

enter image description here

Zooming in a bit closer:

enter image description here

Now I am doubting whether this approach is appropriate, since it generates so many defects that would take an unreasonable amount of time to fix manually.

How can I either :

  • automate the fixing of these defects
  • prevent that these defects occur in the first place? I.e using another method for example...

1 Answer 1


First, you could use "collapse dual lines to centerline" if you had the advanced licence.

Concerning your method, you should use a larger maximum distance with your thin command. This would explain your artefacts.

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