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I'm trying to create a polygon that uses the outer points as the boundary (in layman's terms: connect the dots of the outer points to have one polygon that represents the area).

I've tried using 'aggregate points' and minimum bounding geography' but both of these use the convex hull instead of the bordering points (see image, notice where large polygon area is and no points reside). Looking for recommendations on best ways to do this.

enter image description here

Kadir Şahbaz
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HAYoung
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  • Have you seen this answer? – Matt Feb 15 '22 at 20:18
  • @KadirŞahbaz Yes, I'm using ArcPro – HAYoung Feb 15 '22 at 22:12
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    You are looking for a solution that does not exist. What defines an 'outer point' and at what point are you unhappy with the result? Try generating a Triangulated Irregular Network (TIN)for your points. Convert the TIN to polygons. Manually delete the Polygons you think are too big. Dissolve the result. – GBG Feb 15 '22 at 23:06
  • How do you define which points are "the outer points"? If these are not the vertices of the convex hull, then you need to come up with some rules for what your "outer points" are. If you cannot define which points make up the boundary you want, then no automated process is going to be able to do it for you. – Son of a Beach Feb 16 '22 at 03:12
  • Create TIN, delineate it using very large distance, followed by smaller. Stop, when it looks OK to you. Extract and dissolve triangles to single phone. Delineate with perimeter only option ✔ – FelixIP Mar 04 '22 at 03:03
  • https://pypi.org/project/alphashape/ – Galen Jan 29 '23 at 17:27
  • https://en.wikipedia.org/wiki/Alpha_shape – Galen Jan 29 '23 at 17:27

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See the Concave Hulls discussion and tools at: https://community.esri.com/t5/python-blog/concave-hulls-the-elusive-container/ba-p/902545

There is no simple solution. You have to include rules about how 'tight' you want the "concave-ness" to be. This tool makes it easier to try variations to find what works for you.

Son of a Beach
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