topic Re: Calculate polygon sides in Geoprocessing Questions

Calculate polygon sides

AlejandroMata — Tue, 13 Sep 2011 17:14:57 GMT

Hi all !

I have a polygon shp, and i want to calculate for this shp how many sides has each polygon, as the below image. Is it possible ? im almost sure that it is possible.

Thanks in advanced.

Re: Calculate polygon sides

DarrenWiens2 — Sun, 12 Dec 2021 03:26:41 GMT

This counts vertices, minus 1, in the Field Calculator which should be the number of sides.

Parser:
Python

Expression:

MySub(!shape!)

Codeblock:

def MySub(feat):    
    partnum = 0

    # Count the number of points in the current multipart feature
    partcount = feat.partCount
    pntcount = 0

    # Enter while loop for each part in the feature (if a singlepart feature
    # this will occur only once)
    #
    while partnum < partcount:
        part = feat.getPart(partnum)
        pnt = part.next()

        # Enter while loop for each vertex
        #
        while pnt:
            pntcount += 1   
            pnt = part.next()
   
            # If pnt is null, either the part is finished or there is an 
            # interior ring
            #
            if not pnt: 
                pnt = part.next()
        partnum += 1
    pntcount = pntcount - 1
    return pntcount

Re: Calculate polygon sides

TimothyHales — Tue, 13 Sep 2011 19:19:09 GMT

You can convert the polygon file to a polyline file using the Split Line at Vertices tool. Then Spatially Join the Polygon to the Polyline. There will be a count field in the output.

Re: Calculate polygon sides

TimothyHales — Tue, 13 Sep 2011 19:51:44 GMT

Great code sample Darren. Thanks for sharing!

Re: Calculate polygon sides

DanLee — Tue, 13 Sep 2011 20:25:35 GMT

If your polygons are simple without holes or multiparts, you can do the following:
- Add a field of type = LONG.
- Use Calculate Field tool with this expression: !shape!.pointcount - 1; and specify PYTHON as the expression type.

The resulting values should be the polygon side counts.

Re: Calculate polygon sides

AlejandroMata — Wed, 14 Sep 2011 14:39:08 GMT

Hi folks !

Thanks a lot for your suggestions, i'm going to test your advices and i tell you how i was.

Regards.

Re: Calculate polygon sides

KaylaSnow — Sat, 21 Mar 2020 03:22:20 GMT

This worked perfectly! Thanks