I have a whole lot of polygon shapefiles, many of which have got duplicate nodes. This makes processing difficult as almost all tools (erase, union, calculate area) do not work.

I found that by removing duplicate nodes from the 'offending' polygons the shapefiles become usable. However there are well over a hundred shapefiles and going through all of these is a nightmare.

Is it possible to automate the process using ArcPy or VB? If it is possible, how can it be done?

If not, are there any free libraries in .NET (C# or VB.NET) or Python that can be used to perform this task?

I tried the Python shapefile library (http://code.google.com/p/pyshp) but I found that when it is done removing the duplicate nodes, ArcMap is still unable to handle the shapefiles, giving the same errors as before.


1 Answer 1


Repair Geometry is documented to remove duplicate vertices in shapefiles, see: http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//00170000003v000000

  • You could combine that with arcpy.ListFeatureClasses() to generate a list of the shapefiles in a folder, or arcpy.da.walk() to find all of the shapefiles in the directory tree below a given folder.
    – Bjorn
    Aug 11, 2017 at 1:36

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