Group Connectivity when there is no elevation - Network Dataset

[EmmaButzler]

I don't have elevation in my feature source therefore I need to use group connectivity to ensure that over passes and underpasses are represented correctly. I get an error when i try to set up the group connectivity. 

I am unable to group things because it gives me a warning that there is a disconnect. i am working with all roads from major interstates to local roads. How to group the connectivity? Do i use endpoints or any vertex? 

Any help or explanation of how this works would help!

[MelindaMorang]

I don't think group connectivity is the right way to approach this.  The typical way to handle overpasses and underpasses is to use elevation fields.  You add two fields to your data, like FZLEV and TZLEV, which assign a numerical value (or null) to the two ends of each feature (the from and to ends, in the direction of digitization).  In the locations of overpasses and underpasses, you make sure the FZLEV and TZLEV values match up.  For example, the two endpoints touching in the underpass have a value of 0, and the two endpoints touching in the overpass have a value of 1.  The network will treat the overpass and underpass as disconnected from each other because the elevation fields are different.

Documentation: https://pro.arcgis.com/en/pro-app/latest/help/analysis/networks/understanding-connectivity.htm#GUID-...

I've seen some of your other posts, and it sounds like you're trying to create a network dataset from street centerlines and having some problems getting it to work.  This downloadable set of Pro Tasks is aimed at helping local governments create network datasets from their street centerlines and might help you get started: https://www.arcgis.com/home/item.html?id=9e321cf94d2b43b991cc5109189b2c26