Is it possible to count slivers in a TIN?

I generated a Delaunay triangulation surface model and i want to know how many slivers the TIN has.

closed as unclear what you're asking by Chris W, PolyGeo Oct 28 '15 at 22:01

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    Maybe you could edit your question to say how you made your TINs, which methods you used and how they're represented, so people can give concrete answers. – Rob Skelly Oct 26 '15 at 15:33
  • What GIS software are you using to try and do this? – PolyGeo Oct 26 '15 at 19:20
  • A sliver is a gap or extra polygon along what should be a continuous shared edge between two polygons. Theoretically a TIN wouldn't have any slivers. Are you wanting a count of the triangular faces that make up the TIN? – Chris W Oct 26 '15 at 19:32

You could

  1. create a "world" layer, i.e. a polygon covering your area
  2. do a Clip between the world polygon and your TIN
  3. extract/select polygons with a narrow area (you have to define you threshold area value)

This could lead to the selection of small polygons not being a sliver, but it wil match most of your cases. Otherwise you could restrict the selection calculating a shape factor (maybe circularity could be enough), which will help in selecting elongated polygons.

In QGIS this can be done easily using Processing -> QGIS Geoalgorithms -> Intersection for point 2), and doing a Select by expression using the $area function.

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