topic creation of self intersections in ArcGIS Pro Questions

creation of self intersections

ErichSzerencsits — Wed, 18 Nov 2020 10:40:47 GMT

There are instructions how to remove self intersections, but nothing about their creation and avoidance. I run 'raster to polygon' using 'simplify polygons' in ArcGIS pro 2.63 and 'repair geometry' has to repair nearly all of the resulting polygons due to self intersections and this still doesn’t prevent ‘dissolve’ from crashing because of invalid topology. XY tolerance is set to 0.5 m and the raster resolution is 2 m. XY tolerance of 1 mm results the same. ESRI file.gdb is used.

What is ArcGIS doing and how to prevent self intersections?

Re: creation of self intersections

DanPatterson — Wed, 18 Nov 2020 13:58:37 GMT

compare the simplify polygon version to the non-simplified version You will see your answer. You get unexpected outcomes around the edges of complex rasters with bits being "pinched" off.

Which is why you should always run repair geometry on the result.

Re: creation of self intersections

ErichSzerencsits — Wed, 18 Nov 2020 14:44:55 GMT

Thanks a lot! Well, this is a known but ignored problem?! No hint in the tool-reference of ArcGIS.

It would be great service, having a checkbox to choose if one wants the result of a function with or without geometry errors...

Re: creation of self intersections

DanPatterson — Wed, 18 Nov 2020 18:31:53 GMT

That would apply to all tool use at some point in time.

Now you know 😉

Re: creation of self intersections

ErichSzerencsits — Wed, 25 Nov 2020 14:38:22 GMT

From: https://pro.arcgis.com/en/pro-app/tool-reference/data-management/checking-and-repairing-geometries.htm

"Unfortunately, some of these software packages—sometimes due to bugs, sometimes due to lack of knowledge—do not follow the documented specification."