topic Re: Junction-Edge connectivity in ArcGIS Utility Network Questions

Junction-Edge connectivity

OliviaGill3 — Tue, 13 Feb 2024 17:13:50 GMT

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.

Re: Junction-Edge connectivity

RobertKrisher — Tue, 13 Feb 2024 22:51:18 GMT

Can you post the link to the page in you pulled that quote from so I can pass it along to our doc team?

Junction edge rules apply to any location where a point (device, junction, or junction object) is connected with a line (line or edge object). If the point has terminals, then the rule will also include which terminal on the point the rule applies to. Junction-edge rules most commonly apply to geometric connectivity but can apply to non-spatial connectivity when they involve a non-spatial object (junction object or edge object).

The paragraph you're referring to discusses the limitations of midspan connectivity with terminals which requires either splitting the line or using a non-terminal device to represent the insertion point.

Re: Junction-Edge connectivity

JoaquinMadrid1 — Wed, 14 Feb 2024 00:10:23 GMT

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:

A section of the three-phase trunk is made up of consecutive line segments connected to each other by their consecutive end vertices
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:

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
One asset type for Junction: say Midspan Tapper
- You assign the OOTB Category 'Subnetwork Tap' to this asset type
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
Two J-E Connectivity Rules
- Midspan Tapper to 3-phase
- Midspan Tapper to 1-phase
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
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,

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
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

Propagation of 'ABC' downstream the trunk will not be interrupted by the tapper
The tapper will provide 'B' phase to the lateral

Re: Junction-Edge connectivity

OliviaGill3 — Wed, 14 Feb 2024 09:23:17 GMT

Hi Robert - that's clear, thank you. The link to the quote I used is on this page:

Network rules—ArcGIS Pro | Documentation

Re: Junction-Edge connectivity

OliviaGill3 — Wed, 14 Feb 2024 10:05:36 GMT

Just as an additional comment on the limitations of midspan connectivity with termnials - would this not be managed by implementing an Edge Connectivity rule allowing for AnyVertex. Or in these examples do we need both a Junciton-Edge and also an EdgeConnectivity rule ? Thanks again for your time.

Re: Junction-Edge connectivity

OliviaGill3 — Wed, 14 Feb 2024 10:36:32 GMT

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

Re: Junction-Edge connectivity

RobertKrisher — Wed, 14 Feb 2024 14:38:35 GMT

@OliviaGill3 Terminal devices cannot be drawn midspan on lines, they must split them. Once the line is split the junction-edge connectivity rules apply, but if you don't split the line you get a topology error.

In most cases after splitting the line you will want to connect each line to a different terminal on the device, although in the case of drawing something like a fuse for a tap-line midspan (where it connects to three lines) you would connect the two lines on the upstream edge to one terminal, and the tap line to the other terminal. This configuration allows the fuse to be opened and only interrupt flow to the tap line, leaving flow on the mainline uninterrupted.

Re: Junction-Edge connectivity

OliviaGill3 — Wed, 14 Feb 2024 15:45:59 GMT

Thanks again. I understand how the midspan / terminals for junction edge works now. But in terms of points without terminals for junction-edge:

We have carried out a test on the UN model with some test data. We added a test junction without terminals midspan on a line. The junction has asset group and asset type attribute values of Unknown (and therefore do not exist in the rules configuration). We validated and saw that it doesn't raise an error for junction-edge, only an error where the junction has a non valid subtype. I guess given the premise that:

'Junction edge rules apply to any location where a point (device, junction, or junction object) is connected with a line (line or edge object). ' we would expect a junction-edge error here as well? Any info much appreciated.

Re: Junction-Edge connectivity

RobertKrisher — Wed, 14 Feb 2024 16:07:07 GMT

An asset group/type that is unknown to the system is an invalid feature and I would be careful about using it to draw conclusions about the behavior of the system. Instead, stick to valid asset types and look at how they behave when they do and do not have rules.

Re: Junction-Edge connectivity

RobertKrisher — Wed, 14 Feb 2024 16:10:09 GMT

@OliviaGill3 If you haven't already, I recommend you take the three tutorials in this learn series to help you better understand how to connect features and configure rules: Managing Connectivity with ArcGIS Utility Network. There are also about a dozen articles I can point you to with specific examples for electric, gas, or water datasets.

Re: Junction-Edge connectivity

OliviaGill3 — Mon, 19 Feb 2024 13:55:47 GMT

Hi again - we carried out an additional test as you advised, this time using valid asset groups and asset types on the midspan of a line feature, carried out a validation and again found that there was no error raised for junction-edge. Is it possible that this may be a bug in the system?

Re: Junction-Edge connectivity

RobertKrisher — Mon, 19 Feb 2024 14:51:04 GMT

From your description I'm not sure what the problem is, can you post a screenshot and provide a little more detail on the expected/actual results? (are you connecting things without rules and expecting an error? are you referring to the initial error you received when the asset type was unknown?)

Re: Junction-Edge connectivity

OliviaGill3 — Thu, 22 Feb 2024 10:47:19 GMT

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.

Re: Junction-Edge connectivity

RobertKrisher — Thu, 22 Feb 2024 14:20:04 GMT

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.