I'm working on vector data and want to detect/identify a polygon called narrow/spike like the attached image. Is it possible to use open source software? It can't be done using integrated in ArcGIS. enter image description here

enter image description here

  • Locating spikes is pretty basic computational geometry (atan2 for interior angles past a certain theshold). A colleague of mine did it with FORTRAN and Arc/Info Object code in the late 80s. I did it in the mid-90's in 'C' with shapefiles and SDE. What have you tried? Where are you stuck?
    – Vince
    Jun 10 at 3:18
  • I've also tried topology checker, but it's not the main method to get "spike". And i just tried buffering using qgis, and i don't really understand using "C". using buffers is too risky as it changes all my vector data. for now I just want to detect where there is a "spike" in my large and complicated vector data and fix it maybe manually to make it better. Jun 10 at 3:25
  • You need to walk the vertices, in pairs to compute bearing, then compute change in bearing across pair of segments. Neither FORTRAN nor 'C' is necessary, but coding is likely to be.
    – Vince
    Jun 10 at 11:45
  • okey thank you for your consideration Jun 13 at 2:40


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