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Delete duplicate polylines base on geometry

12-16-2019 11:39 AM
Occasional Contributor II

I have a feature class of polylines that are duplicate, one on top of the other and i would like to delete all except for 1 and it doesn't matter witch one just as long as there is one left. I would like this to be done in arcmap.

I have the following that identifies the duplicates but i am not sure  on how to delete duplicates in the set.

import itertools, arcpy

arcpy.env.overwriteOutput = True
mxd = arcpy.mapping.MapDocument("CURRENT")
df = arcpy.mapping.ListDataFrames(mxd, "Layers")[0]
lyr = arcpy.mapping.ListLayers(mxd, "Parcel_Lines1")[0]

dsc = arcpy.Describe(lyr)  
sr = dsc.spatialReference  
oid_field_name = dsc.oidFieldName  
# get a cursor on the input features  
rows1 = arcpy.SearchCursor(lyr)  
# exclude features already compared once  
exclude = []  
# iterate through the first coursor  
for row1 in rows1:  
    oid1 = row1.getValue(oid_field_name)  
    shp1 = row1.shape  
    # get a second cursor on the same input features  
    rows2 = arcpy.SearchCursor(lyr)  
    # add the feature to be compared to exclude list  
    # create a set to hold duplicate features  
    group = set()  
    # iterate through the second cursor  
    for row2 in rows2:  
        oid2 = row2.getValue(oid_field_name)  
        shp2 = row2.shape  
        # ignore features already compared  
        if oid2 in exclude:  
        # test equality  
        if shp1.equals(shp2):  
            # add both feature ids to the set of identical features  
            # add the feature just compared to the exclude list  
    if group:  # if the group is not empty  
        print group  
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4 Replies
MVP Esteemed Contributor

If you have the Advanced license, might be worth looking into Delete Identical—Help | ArcGIS Desktop 

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Occasional Contributor II

I don't, which is why i was looking into trying to do it with python.

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Occasional Contributor

Take a look at the Geometry Class for ArcPy. It's makes it possible to do some some creative process's on geometry.

So for example if none of the geometry touched each other except for the matching geometry you could write a script to delete only a single geometry from the ones that are touching.

Have a look:

Geometry—ArcPy classes | ArcGIS Desktop 

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MVP Esteemed Contributor

A couple of comments.  First and foremost, you are using the older/legacy cursors, I suggest you move to the newer/data-access cursors.  Not only are the Data Access cursors more Pythonic, they perform much better.

In terms of workflow, if you already have a list of OIDs that represent duplicates, which you appear to, then just setup an update cursor after you are done with your search cursors and delete any record whose OID is in your list.

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