topic Re: Intersecting polygons of same feature class in ArcAPI Questions

Intersecting polygons of same feature class

akshayloya — Tue, 21 Jun 2016 16:48:07 GMT

Hi,

I have a feature class. It has polygons, some are overlapping and some are not. I want to get the intersection of those overlapping polygon in arcmap.

How can I do that? Any help will be greatly appreciated.

Re: Intersecting polygons of same feature class

andrewj_ca — Tue, 21 Jun 2016 16:51:43 GMT

Depending on what the purpose is, you can setup a topology and add rules to it to identify where those polygons intersect (overlap). Let us know your purpose and it might help identify the best solution.

Cheers

Re: Intersecting polygons of same feature class

akshayloya — Tue, 21 Jun 2016 17:02:04 GMT

http://

PFA image. I want to get the area marked in red. It is common area between all the intersections.

Re: Intersecting polygons of same feature class

MicahBabinski — Tue, 21 Jun 2016 17:05:56 GMT

Hi Akshay,

Intersect (Analysis Toolbox) should work for you.

Micah

Re: Intersecting polygons of same feature class

akshayloya — Tue, 21 Jun 2016 17:14:42 GMT

Hi Micah,

Intersection works fine when I have only 2 polygons overlapping.

Akshay

Re: Intersecting polygons of same feature class

andrewj_ca — Tue, 21 Jun 2016 17:25:08 GMT

Hi Akshay,

What about this:

Step 1

Polygon To Line

Creates a feature class containing lines that are converted from polygon boundaries with or without considering neighboring polygons.

then bring it back together like this...

Step 2

Feature To Polygon

Creates a feature class containing polygons generated from areas enclosed by input line or polygon features.

This effectively splits it all up and then reassembles individual polygons. Area should be simple from there.

Re: Intersecting polygons of same feature class

MicahBabinski — Sun, 12 Dec 2021 08:49:14 GMT

Ah, so all of the polygons in the image above are in the same feature class? Andrew's solution looks interesting and may work. Otherwise, you could do something like this:

# import required modules
import arcpy, os

# export each feature into a standalone feature class using a search cursor and the Select GP tool
table = r"Path to your polygon feature class"
fields = ("OBJECTID")
output_workspace = r"path to scratch workspace"
with arcpy.da.SearchCursor(table, fields) as cursor:
  for row in cursor:
      exp = '"OBJECTID" = {0}'.format(row[0])
      arcpy.Select_analysis(table, os.path.join(output_workspace, arcpy.Describe(table).baseName + "_" + str(row[0])), exp)

# create a python list of the feature classes which you just exported
arcpy.env.workspace = output_workspace
fcList = arcpy.ListFeatureClasses("[base name of your feature class]_*")

# perform the intersection using the list of feature classes which you created in the previous step
arcpy.Intersect_analysis(fcList, result_feature_class)

Really, Esri should just roll the above solution into a new GP tool. Split (analysis) doesn't really do it. Let me know what ends up working for you!

Micah

Re: Intersecting polygons of same feature class

DarrenWiens2 — Tue, 21 Jun 2016 17:50:44 GMT

There are some ideas here: https://community.esri.com/message/200113#comment-200113

I'm partial to the solutions offered by Jim W, and... me.

Re: Intersecting polygons of same feature class

akshayloya — Wed, 22 Jun 2016 01:43:58 GMT

Hi Andrew ,

Thanks for the detailed reply. It is making that intersecting part as separate polygon but than I have to remove the other polygon also.

PFA image.

Re: Intersecting polygons of same feature class

FC_Basson — Wed, 22 Jun 2016 06:01:54 GMT

I agree - the Union + Find identical method is quick and simple.

Re: Intersecting polygons of same feature class

akshayloya — Sat, 25 Jun 2016 14:54:39 GMT

Hello people,

Thanks for making an efforts for replying. In my case there were two sets of feature class (Polygons). Both had some overlapping polygons and some were not overlapping. I had to get the intersection of both these files, as in area which is common for all the polygons. So my approach was:

1) Intersected both the files.

2) Union the result of above step

3) Convert it to Feature to Polygon

4) Polygon to Point

5) Than Using "Select by location" selected the polygon in which my centroid (Point) is lying.

Though I'm getting the correct result. Please let me know if I'm following the right path, if not- what will be the best trick of doing it.

Thanks and keep sharing

- Akshay