topic Re: How to check if a Polygon is inside another Polygon w/o using Select By Location? in Geoprocessing Questions

How to check if a Polygon is inside another Polygon w/o using Select By Location?

TrungTran — Sun, 02 Jan 2011 04:20:47 GMT

Happy New Year everyone!!

I need your help on this after googling for days.

I am using ArcGIS 9.3 and want to develop a Python code (Python version = 2.6) to recognize if a polygon is inside another polygon. These polygons are created by codes and not in any shapefiles or feature class. Therefore, I don't want to create a new shapefile to just use Select By Location.
I wish there is something like: aPolygon.contains(aPolygon) = True/False

I tried shapely.geometry but ArcToolbox doesn't recognize this line: "from shapely.geometry import Polygon". Shapely can do the topological relationship very simple.

Any helps is appreciated.

Re: How to check if a Polygon is inside another Polygon w/o using Select By Location?

VivekPrasad — Sun, 02 Jan 2011 11:16:07 GMT

Happy New Year everyone!!

I need your help on this after googling for days.

I am using ArcGIS 9.3 and want to develop a Python code (Python version = 2.6) to recognize if a polygon is inside another polygon. These polygons are created by codes and not in any shapefiles or feature class. Therefore, I don't want to create a new shapefile to just use Select By Location.
I wish there is something like: aPolygon.contains(aPolygon) = True/False

I tried shapely.geometry but ArcToolbox doesn't recognize this line: "from shapely.geometry import Polygon". Shapely can do the topological relationship very simple.

Any helps is appreciated.

Plese check the below forums...they might help you

http://forums.esri.com/thread.asp?c=93&f=993&t=115654

http://forums.esri.com/thread.asp?c=93&f=1729&t=147931

Re: How to check if a Polygon is inside another Polygon w/o using Select By Location?

DanPatterson_Retired — Sun, 12 Dec 2021 06:40:07 GMT

does the script in arctoolbox recognize a straight import of the shapely module? If not, then it may be an installation issue of shapely.
This capability has been added to ArcMap 10 for future reference, through the arcpy module

import arcpy
square = [[0,0],[0,1],[1,1],[1,0]]
small_square = [[0.1, 0.1],[0.1, 0.9], [0.9,0.9], [0.9,0.1]]
pnt = arcpy.Point()
array = arcpy.Array()

for a_pnt in square:
  pnt.X = a_pnt[0]; pnt.Y = a_pnt[1]
  array.add(pnt)
poly1 = arcpy.Polygon(array)
array.removeAll()

for a_pnt in small_square:
  pnt.X = a_pnt[0]; pnt.Y = a_pnt[1]
  array.add(pnt)
poly2 = arcpy.Polygon(array)
array.removeAll()

print "poly 1 contains poly2 :", poly1.contains(poly2)
print "poly 2 contains poly1 :", poly2.contains(poly1)

Re: How to check if a Polygon is inside another Polygon w/o using Select By Location?

TrungTran — Sun, 02 Jan 2011 14:18:33 GMT

Thanks Vara and Dan.

Actually, I can do with VBA but just want to do this in Python because I have some other functions in Python as well.

This command "From shapely.geometry import Polygon" was understood in Python Shell. However, when I created a script and ran it through ArcToolbox, the geoprocessing message window kept saying
--------------------
<type 'exceptions Import.Error'>: "No module named shapely.geometry
Fail to execute (test)."
--------------------

Any thoughts?
Thanks.

Re: How to check if a Polygon is inside another Polygon w/o using Select By Location?

ChrisSnyder — Mon, 03 Jan 2011 15:31:24 GMT

In v10 you would probably have to install any modules you wanted to use via v10 in C:\Python26\ArcGIS10.0 folder rather than the default C:\Python26. Note the similar contents of C:\Python26\ArcGIS10.0\Lib and C:\Python26\Lib.

Re: How to check if a Polygon is inside another Polygon w/o using Select By Location?

BruceHarold — Tue, 04 Jan 2011 12:55:19 GMT

Hi

Not much help at 9.3 I know, but ArcPy geometry objects have a "contains" method:

http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/Polygon/000v000000n1000000/

Regards