topic Re: Long thin polygons in Data Management Questions

Long thin polygons

FionaGregory — Mon, 10 Dec 2012 18:55:10 GMT

I want to identify and remove long thin polygons that surround all or part of other polygons like halo's.

A perimeter/area ratio captures a few of them but not all. Total perimeter in combination with perimeter/area captures a few more, but if I make the ratio's threshold any higher, I start getting valid polygons that I want to keep.

Complications:
- Some are long thin segments connected to an area that is not long and thin (would like to remove the long thin part but not the whole thing)
- This needs to be an automatic process as operational requirements will not allow time to go and individually select polygons

A way to identify the minimum distance between opposite borders of a polygon would help. Or on the raster side, minimum pixel depth. I can do this either as vector or raster.

Has anyone dealt with a similar problem? Any ideas?

Re: Long thin polygons

ScottMoyer — Thu, 03 Jan 2013 12:57:48 GMT

Fiona,
A while back there was an AML named POLYSTATS that did a good job of finding the average width and length of polygons. My bookmark http://www.fs.fed.us/digitalvisions/tools/download/polystats.htm doesn't have the AML, just info about it.
Scott

Re: Long thin polygons

FionaGregory — Fri, 08 Feb 2013 16:31:53 GMT

FYI: ET Geowizards has a tool to calculate thickness and circularity of polygons (Polygon Characteristics) and its Eliminate tool allows you to eliminate on this basis. This is one of the licensed features.