topic Re: Geometric network building: snapping process and when connectivity is established in Data Management Questions

Geometric network building: snapping process and when connectivity is established

JaneOnorati — Thu, 09 Dec 2010 15:40:34 GMT

I'm having trouble understanding what to expect for simple edges based on the guidance given in the 9.3 and 10.0 webhelp:
http://webhelp.esri.com/arcgisdesktop/9.3/index.cfm?TopicName=About_creating_geometric_networks
http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/About_creating_geometric_networks/002r00000008000000/

Are edges snapped within the cluster tolerance at mid-span vertexes or a vertex is inserted and snapped to, but no connectivity is established for either condition (according to 10.0 webhelp)?
Or
Are edges NOT snapped within the cluster tolerance at mid-span vertexes and vertexes are NOT inserted where needed to snap to, and no connectivity established for either condition (according to 9.3 webhelp)?
Or
Something else?

Re: Geometric network building: snapping process and when connectivity is established

CraigGillgrass — Fri, 10 Dec 2010 13:36:52 GMT

The behavior of how simple edges are snapped at mid-span when snapping is enabled during GN building has changed at 10.0.

In 9.3 the behavior was are simple edges NOT snapped within the cluster tolerance at mid-span vertexes and vertexes are NOT inserted where needed to snap to, and no connectivity established for either condition.

As part of the reworking of the GN creation code to provide a more scalable solution, we had to change how this aspect of the snapping model behaves. So, in 10.0 simple edges are snapped within the cluster tolerance at mid-span vertexes or a vertex is inserted and snapped to, but no connectivity is established for either condition.

Re: Geometric network building: snapping process and when connectivity is established

JaneOnorati — Mon, 13 Dec 2010 00:12:30 GMT

Craig,

Thanks very much for clearing that up for me. This is the first time I've actually created a GM, instead of just analyzing one. I think this is an improvement, but I was puzzled why these edges did not become connected.

Can you tell me if there a way to find and connect all these edges that were snapped but not connected during the build using ArcGIS 10? I know I can connect them using the Connect tool on the Geometric Network Editing toolbar, but I'd need to trace every bunch of connected edges and fix them one at a time. I'm working with storm drain data and there are many individual pipe networks in the database.

-Jane

Re: Geometric network building: snapping process and when connectivity is established

CraigGillgrass — Mon, 13 Dec 2010 20:10:39 GMT

The edges do not become connected, because they are simple edges. Connectivity for simple edges is only supported at edge endpoints. You'll need to determine whether this is a data issue that must be corrected (the edge should be physically split) or whether you should be using complex edges to establish connectivity.

You should understand the differences between simple and complex edges before making this decision.