topic Re: Problems when verifying topology in Geoprocessing Questions

Problems when verifying topology

FabioGrita — Thu, 14 May 2020 13:03:02 GMT

Hello, I am really struggling to validate the topology of a dataset. I tried in many ways and with different formats. I also tried to verify a subset of the data (like the one attached), but it takes long time (even days) and at the end I get the error message below.

I applied 2 basic rules: Must not have gaps (area) and Mist not overlap (area).

I use a personal license of ArcGIS Pro 2.5

Can anybody help?

Many thans

Fabio#

Re: Problems when verifying topology

DuncanHornby — Mon, 01 Jun 2020 15:38:07 GMT

You have multiple issues here:

Having downloaded your sample and built a topology I realised that the test must not have gaps makes no sense as your data has islands. If they did not have a gap then they would not be an island!
Validation is taking a long time as your data is 1 giant multipart feature, you need to explode that out into single parts, then create your topology on that, then validation is less than a minute for must not have overlaps.

Re: Problems when verifying topology

DanaNolan — Tue, 09 Jun 2020 15:47:43 GMT

I have to work with topologies, not of my design, that generate such errors. There are a huge number of exceptions and overlapping errors and exceptions, but one of the bad areas that triggers the error is less than 100 square meters (out of a million+ acres) and has almost no data in it. So I think the topology engine must be producing bad geometry or just simply can't handle something there. If I turn on Task Manager while these bad areas are being validated, I can see ArcGIS slow down to almost no read/write activity, but it will continue for at least 10 minutes until it fails if I don't cancel validation.

I mapped the bad areas, which I digitized as a few polygons. Then I validate in sections, avoiding these areas. This works, but even when I have had to rebuild the topology due to feature name changes, the bad areas are always there.

Re: Problems when verifying topology

DanaNolan — Tue, 09 Jun 2020 15:53:35 GMT

Topology rules often don't make sense for most of the data. Especially true if someone at a higher level created them for several departments/organizations. They are just there to force you to look at the data and decide whether there is a real error there. I probably have a 500 to 1 exception to real error ration, but that is what exceptions are for.