topic Re: Minimum length & width of irregular polygons in Geoprocessing Questions

Minimum length & width of irregular polygons

LisaAngstadt — Wed, 13 Feb 2013 19:15:39 GMT

I have had a request to find polygons within our parcel layer a with minimum width of 1000' and length of 1000'. I tried converting polygons to lines, but not all lines are split appropriately, so it did not yield correct results. The majority of our parcels are irregular polygons, so I cannot use the Bounding Box tool. Any suggestions?

Thanks,
Lisa Angstadt

Re: Minimum length & width of irregular polygons

DanLee — Wed, 13 Feb 2013 19:46:54 GMT

Are you looking for the edge of minimum length for each parcel? If so, try:

1. Run Slit Line At Vertices tool; it works for polygons too. The output lines carry input poly IDs (ORIG_FID).
2. Run Summary Statistics tool on the split lines, using the ORIG_FID as case field and specifying MINIMUM for shape_length field.
3. If necessary, use Join Field tool to transfer the minimum_shape_length from the summary table back to input polys via the OBJECTID and ORIG_FID.

Re: Minimum length & width of irregular polygons

BruceHarold — Thu, 14 Feb 2013 14:05:10 GMT

Hi

See if you can use this:

http://www.arcgis.com/home/item.html?id=9398bd2232cb4c8490b0b05015364d28

Regards

Re: Minimum length & width of irregular polygons

LisaAngstadt — Thu, 14 Feb 2013 16:49:27 GMT

Hi Bruce,

We are still at 10.0. Will the Fishnet tool work with it?

Thanks,
Lisa

Re: Minimum length & width of irregular polygons

LisaAngstadt — Thu, 14 Feb 2013 18:16:55 GMT

Dan,

I tried the split vertices tool, but it didn't yield the results I need. Maybe it would be better to describe the request as finding parcels that have an area of at least 1000' x 1000'? But because the polygons are irregular, it would need to be two perpendicular sides with at least 1000', if that makes it any clearer!

thanks,
Lisa

Re: Minimum length & width of irregular polygons

curtvprice — Thu, 14 Feb 2013 18:21:04 GMT

it would need to be two perpendicular sides with at least 1000', if that makes it any clearer!

If you have access to Spatial Analyst, you may want to try Zonal Geometry As Table using a unique polygon identifier as the zone value. The Thickness value this tool calculates may be what you need.

Re: Minimum length & width of irregular polygons

DanLee — Thu, 14 Feb 2013 22:45:25 GMT

Lisa,

Are you trying to find parcels to fit a 1000' x 1000' square or a circle of 1000' diameter inside?

Re: Minimum length & width of irregular polygons

BruceHarold — Fri, 15 Feb 2013 14:13:09 GMT

Hi Bruce,

We are still at 10.0. Will the Fishnet tool work with it?

Thanks,
Lisa

Hi Lisa
The tools needs 10.1 sorry.
Regards

Re: Minimum length & width of irregular polygons

LisaAngstadt — Fri, 15 Feb 2013 16:24:49 GMT

Lisa,

Are you trying to find parcels to fit a 1000' x 1000' square or a circle of 1000' diameter inside?

Dan,

I believe we are looking for 1000' x 1000' square minimum areas. Still have not found a solution!

thanks,
Lisa

Re: Minimum length & width of irregular polygons

DanLee — Fri, 15 Feb 2013 18:15:01 GMT

Lisa,

Fittinng a square inside a polygon is more complicated than fitting a circle because the same square can fit different space/width when rotated. Try the following, which ensures the suitable polygons found are at least as wide as the diagonal of the square:

1. Run Buffer tool using a negative distance, -707' about half of the diagonal of the square. The output polygons are all inside input polygons that are at least as wide as the diagonal of the square. The output polygons may be multipart. You can center the square at any location inside these buffer polygons without going outside of the input polygons.
2. Run Spatial Join (or select layer by location) tool to join the input polygons with the buffers using INTERSECT or CONTAINS match option; the joint polygons are suitable for the square.

Optional:
- After step 1, run Multipart To Singlepart tool on the buffer polygons to make them singlepart. That way you will know if an input polygon is joint with more than one singlepart buffer polygons in step 2.

Hope this helps.

Re: Minimum length & width of irregular polygons

JamieSorensen — Fri, 15 Feb 2013 21:51:03 GMT

I believe I had to do something similar recently. Try this:

http://resources.arcgis.com/gallery/file/geoprocessing/details?entryID=3D230972-1422-2418-34A5-2F3FFF97C238

If you use the 'minimum bounding rectangles' option, you will be able to get a length and width for every individual polygon.

Re: Minimum length & width of irregular polygons

JoelCalhoun — Fri, 15 Feb 2013 21:54:12 GMT

I had trouble getting to the previous poster's link so I though I would recommend using Esri's Minimum Bounding Geometry tool.

First I would explode your parcels into single part features and then instead of using a fishnet you could create bounding envelopes around the exploded parcel polygons.
The shape of the envelope depends on the method selected. Most of the options output a polygon envelope containing the input feature class attributes and if you check the box "Add geometry characteristics as attributes to output (optional)" the length and width. You could then do a selection for any that have both an MBG_Width and and an MBG_Length >= 1000'.

Best of luck,

Joel