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Junction-Edge connectivity

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02-13-2024 09:12 AM
New Contributor III

I've been doing some reading on different types of Geometric connectivity in the UN and am trying to find some clarification re: Junction-Edge connectivity. I believe this can only be applied to a line and a junction as a geometric connection, and only with a junction that has a terminal where the junction must be at the end of the line, rather than placed midspan. Is this correct?

The documentation is not completely explicit (which may be my misreading) but it explains that:

'Establishing a connection midspan along a line or edge object to a point or junction object with terminals requires a nonterminal point feature or junction object to be placed midspan, respectively.'

Doesnt this mean, by having a non-terminal point midspan that is connecting geometrically to a line, the rule statement is essentially contradictory? Any help or clarification is very much appreciated. 

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13 Replies
New Contributor III

Hi Robert - apologies for the late reply. We added a point at the end of a line where a rule is not yet present in the B_Rules table, with values for the asset group and asset type. So as expected this flagged a dirty area with the following error: no junction-edge rule to support the connectivity. This is what we'd expect.

We then added a point at the midspan of a line. This point has the same asset group and asset type of the previous point added at the end of the line. However this did not raise the same dirty area error (no junction-edge rule to support the connectivity). Our expectation would be that it should raise an error for both scenarios - end and midspan of the line and it only raised the error when the point was added at the end of the line. Thanks for your help, it is appreciated.

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Esri Regular Contributor

That's not the expected behavior. Please post a screenshot and describe exactly how you placed this feature midspan on the line. The software doesn't snap features that aren't allowed to connect, so unless you're forcing them to be snapped it's likely that the midspan feature isn't coincident with the line.

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New Contributor III

As a follow up to Robert's explanation, let me elaborate using an Electric Utility use case nicely resolved by the UN: tapping a phase from a three-phase trunk down to a single-phase lateral.

In this (informal) example, consider the following:

  1. A section of the three-phase trunk is made up of consecutive line segments connected to each other by their consecutive end vertices
  2. You may want to tap
    • Either any where within a single segment of the trunk (midspan tapping)
    • Or where two segments connect (line end tapping)
    • Or where a "last" segment finishes off the three-phase trunk (also line end tapping)
    • The lateral stems off the trunk at this tapping point

Then you need to configure your UN as follows:

  1. Two asset types for Line: say 3-phase and 1-phase (the names are not relevant)
    • The 3-phase asse type must have Edge Connectivity Policy of 'Any Vertex' so that you can snap
      • Either at any End Vertex
      • Ot anywhere Midspan, allowing a new vertex to be created if at the snapping point there was not already one
      • NOTE: this workflow relies on ArcGIS Pro's Snapping Engine
  2. One asset type for Junction: say Midspan Tapper
    • You assign the OOTB Category 'Subnetwork Tap' to this asset type
  3. One asset type for Device: say Line End Tapper
    • You assign a terminal configuration to this asset type with two terminals, say
      • Connect to 3
      • Connect to 1
    • NOTE: The need of terminals forces the Line End Tapper to be a Device
  4. Two J-E Connectivity Rules
    • Midspan Tapper to 3-phase
    • Midspan Tapper to 1-phase
  5. Two J-E Connectivity Rules
    • Line End Tapper to 3-phase via Connect to 3
    • Line End Tapper to 1-phase via Connect to 1
  6. Configure your UN for Phase Propagation, driven by a phase network attribute, say E:Phase Driver
    • Assigned to a phase field in the Device, Junction and Line feature classes

NOTE: I am illustrating this example without Non-Spatial Objects. But they could also be used accordingly.

With all this machinery at your disposal,

  1. If you want to tap midspan, bring a Midspan Tapper to the map
    • It will snap to the 3-phase
    • You set the phase driving value, say 'B'
    • You bring a 1-phase to the map, which will snap at the tapper
  2. If you want to tap at a n end vertex, bring a Line End Tapper to the map
    • It will also snap at the end vertex of the 3-phase
    • You also set its phase driver to 'B'
    • And you can also pull the lateral starting from it snapping to the tapper

In either case, if the Propagator were bringing 'ABC' phase from upstream, then

  1. Propagation of 'ABC' downstream the trunk will not be interrupted by the tapper 
  2. The tapper will provide 'B' phase to the lateral
New Contributor III

Hi Joaquin - thanks for the very detailed response and example. I'll have a read! There is so much to learn!

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