How to Find Errant Points that are Duplicates but Not Identical

Blog Post created by geonetadmin on Jun 8, 2010

Hello, this is Cassandra with a cool solution for cleaning inaccurate point data. I worked with a customer recently who had received a data set with points representing residential electrical meters, which unfortunately had a lot of duplicate points. The customer was able to remove the identical duplicates by using the 'Delete Duplicated Features' script available from ArcScripts, but he found numerous other points that were obviously duplicates but were not identical geographically. Most of these erroneous points were within 2 centimeters (cm).

As the dataset contained thousands of points, manually searching the entire data set was out of the question, so the customer turned to Esri Support for ideas on identifying the duplicate but not identical points so he could delete them.

With the help of a colleague, we provided the following solution: create a buffer on the points dataset with an extremely small radius value, for example 3 cm.

Run an intersect on the buffer polygon result. Because the buffers are tiny, the only polygons in the intersected results will be located where two points are within 6 cm of each other.

The customer was then able to zoom to each of these polygons from the attribute table and manually delete the erroneous point.

This method may not work for every situation, but is a good example of how to use some of ArcMap tools to tackle a problem.

Please provide any questions or comments that you may have via the comments section below this post. NOTE: You must be logged in to your Esri Global Account to leave comments.

- Cassandra L., Desktop Support Analyst, Esri Support Services