Connectivity Problem

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08-18-2010 04:21 AM
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New Contributor
I am trying to set up a network in which there are 11 subway routes, 2 walkway routes and 3 stops. I am using it to find the shortest commuter route across a city. The 3 stops are connected by the 2 walkways (1 stop is connected to the 2 others). I want no connectivity between the subways, but if a route passes one of the stops it should be able to change lines via the walkways (or else if the stop is common to another line).
When I run closest facility in network analyst I get an error saying no facility found for incident x.
Attached is an image of my connectivity policy.
Anyone know how I can achieve what I want to do?
Thanks in advance.
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Having read another similar post I feel I should add a bit more detail to save some time. My incident points are not part of my network dataset and neither are my facilities. The stops are though. I have never had a problem doing it this way before, until I decided to introduce connectivity.
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Are you sure that the line features from the other connectivity groups have coincident vertices where your stops are located? It does not suffice for your stops to merely be geographically "on top of" the line features. In order for your stops to "connect" to the other line features from the other connectivity groups, the line features must have existing vertices where the stops are located along the lines. Otherwise, the stops will not be allowed to "connect" to these lines. Does this make sense? Please check this first, and we can proceed from there. If you need to establish vertices where your stops are located along the line features, you can run the 'Integrate' geoprocessing tool.
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Thanks for getting back to me Michael. Well, I used the trace tool to create the stops. I snapped to the lines, which I assumed would only allow me to land on a vertex, as I figured there would need to be common vertices for the connectivity to work. I will try the integrate tool now and see if that makes a difference. I'll report back with how I get on!
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I just tried to integrate the various lines and stops. Is there any way of verifying whether anything changed? I tried running the closest facility again using the integrated data, under both honor and override for the stops, and I'm still getting the same results (being none). I am using an XY tolerance of 10 meters when integrating. In the documentation it says to use something "small", but that's a bit vague. Considering that I used trace to create them I doubt they could out by much more than 10m. Is there anything I could try? Or any other reasons it wouldn't be working?
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New Contributor III
Have you tried using the Network Identify tool (on the Network Analyst toolbar in ArcMap) to click around your network dataset and see where you might have connectivity issues? For example, you can click on one of the subway routes near one of your stops, and see if there is an appropriate adjacency from the subway line (through the stop) to a walkway line.

If the connectivity appears to be okay per your specifications, then try looking at the cost and restriction attribute values for some of those elements. If they have negative cost attribute values or are restricted for some set of restriction attributes that you are using in your analysis, then this could be your problem.

Let me know what you find, and we can proceed from there.
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I used the identify tool and the stops are adjacent to my routes. I have no negatives nor restrictions in my network. It's starting to frustrate me! Is there anything else I can do?
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New Contributor III
Perhaps next you could try using the identify tool to progressively find a path of adjacent elements from your starting incident to your destination facility. If there is truly no valid path (which the solver suggests), then perhaps you will see where any potential connectivity problems are coming from.

If this does not help at all, then, if your data is small enough, perhaps you can zip it up and post it here for further review. I will warn you, however, that there have been problems with opening up attached .zip files on these forums, and I don't know when these will be properly addressed, so it may end up being a wasted effort.

If all else fails, you can always report the issue to ESRI technical support. They can work directly with you to look at your data and help you figure out the source of the problem.
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