topic Re: Topology Errors: Removing slivers and gaps between polygons in Data Management Questions

Topology Errors: Removing slivers and gaps between polygons

ScottGordon1 — Thu, 28 Apr 2011 20:53:26 GMT

Hey Guys,

I have a bit of an issue, i have a several topology errors , more specifically i have several gaps and slivers. i have tryed the intergrate tool, merging the polygons as well as the eliminate geoprcessing tool. these all got rid of the gaps and slivers, but also caused a loss of some important attribute data. im looking for a way to fix the gaps and slivers without having to snap the entire township and without loosing data. any suggestions would be greatly apprcieated as i am stil a bit green under the ears.

P.S. i do have an ArcInfo licence

Thanks all.
Scotty

Re: Topology Errors: Removing slivers and gaps between polygons

Robert_LeClair — Thu, 28 Apr 2011 21:08:02 GMT

Hi Scotty -

I would consider building a geodatabase topology to find my spatial errors. Please see the following URL for details: http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/An_overview_of_topology_in_ArcGIS/006200000001000000/

Regards,

Robert LeClair
Esri-Denver

Re: Topology Errors: Removing slivers and gaps between polygons

ScottGordon1 — Fri, 29 Apr 2011 16:04:25 GMT

so i figured out how to do it. for future reference. to fox the overlaps all you have to do is merge using the topology error inspector. to fix the gaps i found the simpleist way was to modify the shape of the edge along the gap so that it overlaps the adjacent polygon then again using the error inspector merge the polygons. with over 500 errors in total it took me 6 hours to completly fix all of the errors. i could only guess how long it would take to snap everything...maybe 2 weeks.

I hope this helps anyone with similar problems.
Cheers,

Scotty G

Re: Topology Errors: Removing slivers and gaps between polygons

JohnSobetzer — Mon, 02 May 2011 12:57:41 GMT

That's a lot of work. Sometimes manual work is required but if you can accept some minor vertice moves an automated process can do a lot. What attributes did you lose when you used the Integrate or Eliminate tools?

Ideally, there would be a batch topology fix for gaps and overlaps but I don't know of any. Maybe I missed that and someone can point us to it.

I like to use ETGeowizard's clean and eliminate tools when I'm given a topologically messy polygon set, but these aren't the free tools. Since you have ArcInfo you could use the Feature to Line and Point tools, then Feature to Polygon using the points for attributes. It would fill in all the gaps and the overlaps would become their own polygons, both of which would lack attributes. (Well, it is possible a point would get into a sliver rather than the "home" polygon so you would have to check for that.) Then run an Eliminate, but check the results; you may have to vary the tolerance to get enough eliminated without unacceptable vertice movement.