Topology rule to check connectivity between two layers

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04-14-2021 07:38 AM
AlinaT
by
New Contributor III

Is there a topology rule I could use to check whether my sewer lateral lines are correctly snapped to my sewer mains? I have looked at "Must not intersect" which will identify if there are any overshoots but I can't find a rule that would find the undershoots. 

Thanks! 

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jcarlson
MVP Regular Contributor

There are all sorts of topology rules you can use, depending on the situation. Are the laterals and mains subtypes of a layer or different layers?

Esri has a nice topology cheat sheet you can keep handy. I would probably create a general nodes feature class, that way you can use "Endpoints must be covered by". But that could be a bit of work to create the nodes if they don't already exist.

- Josh Carlson
Kendall County GIS
AlinaT
by
New Contributor III

Thank you, I do have the poster and it is a handy resource!

The laterals are in a separate layer than the mains. I do have a few other point layers in the dataset. For instance I have a tap layer and I have been testing a combination of these two rules: 

1) Taps must be covered by sewer mains.

2) Taps must be covered by endpoint of laterals. 

The problem with this, we don't have all taps GPSed/digitized and also we have lots of taps but no laterals (these came from CCTV inspections of the mains) I was hoping there was a simpler way to check the connectivity of the two layers, but maybe I do need to go a different route.

 

Thanks!

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jcarlson
MVP Regular Contributor

Well, if you just want to find the undershoot features, you can spatially select based on intersection with the mains, then check the box to invert the where clause.

If you want to force all laterals to snap to the mains, consider the Snap GP tool. It won't address the lack of topology features to enforce a real rule, but can get them all into compliance with the desired end result.

- Josh Carlson
Kendall County GIS
AlinaT
by
New Contributor III

Thank you, those are great suggestions! 

 

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JayantaPoddar
MVP Esteemed Contributor

This tutorial also guides you to fix undershoot and overshoot errors, among fixing other line errors.

Exercise 4b: Using geodatabase topology to fix line errors