Why does the overlap check not find duplicate geometries?

[JustinCarasick]

I run the overlap check but it does not pickup features where they are completely overlapping (ie. duplicate geometries with different attributes). Is there a setting I can specify to capture these or do I have to run two seperate checks (overlaps and duplicates)?

[T__WayneWhitley · Accepted solution]

There is Find Identical in Data Management...don't know if you were okay with using another toolbox.  Also, I don't know how 'close' your 'completely overlapping' features really are, but the webhelp states you can select the Shape fields to compare geometries....just don't know how close a tolerance there is (I imagine they should be 'identical' within the fc cluster tolerance).

Hope that helps.  Here's the webhelp link (for 10):

Find Identical (Data Management)
Resource Center » Professional Library » Geoprocessing » Geoprocessing tool reference » Data Management toolbox » General toolset
http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//001700000054000000


EDIT:  Actually, I think you may be looking for a similar tool in Data Reviewer --- Duplicate Geometry check.  I believe the 'overlap' tool is mainly for comparing with another feature class?  No, I was wrong -- interestingly, the 'why' of this is because this tool is based on a topological intersection of boundaries producing 'gaps' or 'slivers'...so I suppose a completely overlapping feature with another produces no such thing, neither gap or sliver, actually nothing in this manner to flag as an error.

Finding duplicate geometry
Resource Center » Professional Library » Extensions » Data Reviewer » Automating validation with checks and batch jobs » Validating data using checks » Duplicate Geometry checks
http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/Finding_duplicate_geometry/01020000002...

[JustinCarasick]

I ended up adding the duplicate geometry check and that works but just seemed strange to me that it is not picked up by the overlap check. You can use both of these tools on the same featureclass and is what I am doing. The combination of the two checks (overlap and duplicate) do work though. The geometries were exactly the same with different attributes. I would consider this an overlapping feature but is odd that not picked up by that check.

your last point of the gaps/slivers makes sense as to why not picked up.

thanks

[JohnDean1]

I might point out that the Data Reviewer 'overlap' rule will not be violated by concentric overlaps; for example, a smaller circle inside a larger; moreover, it won't find perfect overlaps (duplicates). This is presumably because, as in the previous comment, 'overlap' is violated where edges cross. I recommend 'intersect'. This rule in Data Reviewer is violated by all types of overlaps: concentric, perfect, etc.