topic Re: Increase size of polygon circles in Geoprocessing Questions

Increase size of polygon circles

DeannaMetts — Fri, 28 Jan 2011 12:57:40 GMT

I have a polygon feature class with thousands of circles. Most of them are the correct diameter, but some are not. I need to increase the size of all of them to have a 15' radius.

What is the easiest way to do this?

Re: Increase size of polygon circles

DanPatterson_Retired — Fri, 28 Jan 2011 14:33:52 GMT

1 selecting/query the ones that are the correct size and export to a new shapefile
2 switch the selection determine the centroid of those that have too small radii, make them their own shapefile
3 buffer the points in step 2 to the correct size
4 merge the results of 1 and 3 together

Re: Increase size of polygon circles

DeannaMetts — Mon, 07 Feb 2011 12:01:24 GMT

Thanks, but how do I determine the centroid?

Re: Increase size of polygon circles

DanPatterson_Retired — Mon, 07 Feb 2011 16:47:11 GMT

add two Double fields to the table with appropriate precision and scale and check out the topic on field calculations
http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//005s00000025000000.htm
once the centroid X and Y are determined add the table in as an event layer using the X and Y fields...there are alternates that require different extensions or license levels, also check the various script sites for tools to convert poly* features to their centroid representations

Re: Increase size of polygon circles

DeannaMetts — Thu, 03 Mar 2011 19:43:53 GMT

Thanks for the suggestions. It was no trouble to get the centroids and then use the buffer wizard to create the correct size circle polygons. The problem I am having now is that the buffer polys do not have the attributes I need to keep from the original shapefile. Im sure there is a way to merge or join and get what I need, but so far I have not figured it out.

Re: Increase size of polygon circles

DanPatterson_Retired — Thu, 03 Mar 2011 20:04:45 GMT

you answered your own question....join using the FID field (assuming you are using shapefiles). To make the join permanent, simply export the file to a new file (in v 10,right-click on the layer, Data, Export Data etc)