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Split polygon feature by percentage

JayantaPoddar

Hi friends,

I have a feature table with a field (Float) containing percentage values which aggregates to 100%. And I have one big polygon. I need to split the polygon based on the percentage values from the table.

I have seen a similar tool in ET's GeoTools.

http://www.ian.ko.com/ET_GeoTools/UserGuide/ETSplitPolygonByArea.htm

But I don't have the tool.

Is there any workaround in ArcGIS? Maybe using Python?

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AlexMarczynski2

Has there been any advancements to this error? I am attempting to use the script but am coming back with the same error as Vaibhav. I have changed the SpatialReference to my data.

FC_Basson

Seems like the cutting line is not intersecting with the polygon. Is the spatial reference of the polygon also 4326?

Vaibhavsingh10

after implementing i am getting following error:

Runtime error
Traceback (most recent call last):
File "<string>", line 42, in <module>
File "c:\program files (x86)\arcgis\desktop10.5\arcpy\arcpy\arcobjects\arcobjects.py", line 867, in cut
return convertArcObjectToPythonObject(self._arc_object.Cut(*gp_fixargs((other,))))
RuntimeError: A polygon cut operation could not classify all parts of the polygon as left or right of the cutting line.

Please help!!

DanielThen

Hi FC Basson,

Thank you for sharing the code. I have tried to adapt it to work for my layer but it came up with an error:

Runtime error

Traceback (most recent call last):

File "<string>", line 36, in <module>

File "c:\program files (x86)\arcgis\desktop10.2\arcpy\arcpy\arcobjects\arcobjects.py", line 825, in cut

return convertArcObjectToPythonObject(self._arc_object.Cut(*gp_fixargs((other,))))

RuntimeError: A polygon cut operation could not classify all parts of the polygon as left or right of the cutting line.

line 36: cutlist = cutpoly.cut(pline)

Do you have any idea the error came up?

Regards,

Daniel

JacobSiech1

Hi FC Basson,

Thanks for the reply. I changed the value or at lease added a value to the X-value and it work like you said. However I am still a little hazy on how to find the value using an angle. I just use trial and error for one of the polygons but this will obviously not work for more than 200 polygon that I have to do. I guess I could find the value for each the first time and put it in an attribute and add that value to the X-value but that could take some time. Is there a way to calculate this value using the attribute calculate functions?

Thanks,

~J~S~

FC_Basson

Automating the process to detect the angle of the correct side might be tricky unless you provide it as an attribute for the polygon feature, but you can definitely cut at an angle by setting different X-values for the cut-line's start and end points (lines 38 and 39) - you just need to determine the difference based on the required angle.

JacobSiech1

I got the code to work however I wanted to know if there was anyway to have the code cut the polygon parallel to one of the sides. Since in my case I am cutting rectangles I would like it to cut those rectangles parallel to one of the side. Is this possible?

Thanks,

~J~S~

JacobSiech1

Hi Wes,

Yup you are right I found that my projection was different than that was in the code so I changed it and now it work yea. Now I just need to adapt the code to do multiple polygons and to cut the polygon based on attributes You wouldn't have any input on how to go about doing this? Any help would be great.

Thanks,

~J~S~

WesMiller

Could you post the code you are currently using? If you are using the code from above line 40 sets a spatial reference that may be different from the feature class you are using.

JacobSiech1

Hi again,

I fixed the last issue but now have another. This is the error that comes up:

Traceback (most recent call last):
File "C:\Users\jacob.siech\Desktop\TestScript.py", line 42, in <module>
cutlist = cutpoly.cut(pline)
File "c:\program files (x86)\arcgis\desktop10.4\arcpy\arcpy\arcobjects\arcobjects.py", line 859, in cut
return convertArcObjectToPythonObject(self._arc_object.Cut(*gp_fixargs((other,))))
RuntimeError: All geometries involved in this operation must have the same spatial reference.

I have checked the spatial reference of the data fraim and the layer and they are the same. So I do not know what to do now. Any help would be great.

Thanks,

~J~S~

JacobSiech1

Hi FC Basson,

I wanted to know if you could help me with your script that you have. It does not want to run for me. It gets to line 13 and says, " with arcpy.da.SearchCursor(poly, ["SHAPE@"]) as pcursor: TypeError: 'in_table' is not a table or a featureclass" do you know what might be causing this?

Thanks,

~J~S~

JacobSiech1

Hi,

I have a similar issue however I have multiple polygons in my case some 200 polygons and I would like to split them based on a percentage. I don't really know how to structure my data either to achieve my end result. Basically I have 200 building footprints each building has multiple tenants and I want to split the polygons by the percentage of space each tenant is occupying. Currently I have all the polygons or building footprints in one layer and all the tenants in a point layer. I have looked all over and have found no solution to this problem any help would be great.

Thanks,

Jake

FC_Basson

You can try this script. I'm not familiar with the ET-Geotools version, but I think it does more or less the same. It adds the split parts to the existing polygon layer, but you can change it to write to a new feature class.

import arcpy

mxd = arcpy.mapping.MapDocument('CURRENT')
df = mxd.activeDataFrame
layers = arcpy.mapping.ListLayers(df)
# select layer - my known polygon layer with only one polygon
poly = layers[2]
# split steps
splits = [20, 30, 50]


# get polygon and extent properties
with arcpy.da.SearchCursor(poly, ["SHAPE@"]) as pcursor:
   for prow in pcursor:
      polygon = prow[0]    # polygon to cut
      e = polygon.extent   # bounding extent of polygon
      print e.XMin,e.YMin,e.XMax,e.YMax
del pcursor


# geometric cut test iteration step size - modify value to get better accuracy
stepsize = 0.001
# set parameters to move from left to right over the polygon
leftXstart = e.XMin
leftX = e.XMin + stepsize
ymax = e.YMax
ymin = e.YMin

cutpoly = polygon
icursor = arcpy.da.InsertCursor(poly, ["SHAPE@"])
# iterate cut percentage list
for i in splits[:2]:
   print i
   tol = 0
   while tol < i:
      # construct NS line
      pntarray = arcpy.Array()
      pntarray.add(arcpy.Point(leftX, ymax))
      pntarray.add(arcpy.Point(leftX, ymin))
      pline = arcpy.Polyline(pntarray,arcpy.SpatialReference(4326))    
      # cut polygon and get split-parts
      cutlist = cutpoly.cut(pline)
      tol = 100 * cutlist[1].area / polygon.area      
      leftX += stepsize
      #print str(leftX) + ":" + str(tol)
   cutpoly = cutlist[0]
   # part 0 is on the right side and part 1 is on the left side of the cut
   icursor.insertRow([cutlist[1]])
# insert last cut remainder
icursor.insertRow([cutlist[0]])
del icursor

This is the result for cutting the polygon into 20%, 30% and 50%

JayantaPoddar

Hi Wes,

Thank you for sharing the link. But my problem is different. The polygon needs to be split into variable sizes (area) based on the percentage value from another table.

WesMiller

Did you see this thread Advice for splitting polygon into several "strips"

JayantaPoddar

Second one is a table.

You can create a sample as below.

Create any random polygon (with UTM/WGS_1984 projection).

And a table with 4 records where a field <Field_Per> will have values of say 20, 35, 15, 30 for the four records.

Thanks again for your efforts.

Anonymous User

Hello Jayanta,

Looks like you have one polygon and another one is feature or one table with % values.

If both are features, then overlay works and for another I need to test in my system.

Let you know my findings.

can you please give me yours sample files.

Thanks

JayantaPoddar

Hello Avinash,

Thanks for your quick response. The above tools you mentioned, splits the polygon feature parts from the feature class and exports them to different feature classes.

My case is a little different. My polygon feature class has only one polygon (01 record). And the splitting should be based on the percentage values from another GDB table.

An example of resulting polygon is attached (ET GeoTools used in this case).

Let me know if you have any further suggestion.

SplitPolygon.JPG

Anonymous User

Hi
You can use below tools,

Split By Attribute Tool - Desktop Decision Support Tools

http://www.arcgis.com/home/item.html?id=15ca63aebb4647a4b07bc94f3d051da5

i am 100% sure but one of them help you.

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