Network Analyst -- No route between two locations

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05-26-2020 09:55 AM
JeremyScott
New Contributor II

I am attempting to create routes between bus stops using Network Analyst. In some cases, I get an error message that says there is no route between two locations. I have played around with the topology in case there were issues there (increasing xy tolerance to 1ft) and I have also set the directionality for all segments to be bidirectional. Both of these were in an attempt to get a temporary solution. I am not exactly sure what to look for in determining what the issue is. I have attached a screenshot showing the two points that cannot be routed along with the error message.

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13 Replies
JaySandhu
Esri Regular Contributor

Jeremy,

Looking at the data explains the issue. Your street line data is 3D! So even though the X,Y may be the same, the Z values are not. For example, the three lines around bus stop feature 20 that do not connect have the following vertices:

15411, 2011544.876, 787417.068, 247.212
15521, 2011544.876, 787417.068, 247.212
5530, 2011544.876, 787417.068, 244.100

Even though the X and Y are the same, the Z values of one of them, 244.1 does not match the 247.212 of the others. Visually:

You could either fix the data at the places the z's do not match or drop the z's and rebuild the network

Jay Sandhu

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JaySandhu
Esri Regular Contributor

The streets around junction 49 are not connected to anything:

I did a service area lines for 30,000 feet around junction 52 and say many disconnected areas: Purple is the reached service area lines over the blue streets. I put yellow circle around some of the disconnected edges.

Jay Sandhu

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JeremyScott
New Contributor II

Jay,

I meant the OBJECTID off the bus route layer, not the junctions layer. I

know there are a few instances of 'islands' due to cutting the network

dataset to our service area. I may have to expand to ensure this does not

happen with the final product. However, catching the differences in the

z-coordinate was the difference (I am assuming you manually calculated this

or was there another step you did to find this discrepancy?). This was not

something that I would have thought and probably should have just removed

it from the network dataset to start with since I wasn't worried about

elevation. After removing elevation from the network dataset, I was able to

route 1031 bus routes (all but 9). I will dig deeper into these 9, but I

have a feeling they will be based on the issue you raised about the

'islands'.

Thank you so much for your assistance!

Jeremy

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JaySandhu
Esri Regular Contributor

I meant to say ObjectID not junctionID. Those 49 and 52 were the ones you mentioned, so I was using them in the examples. Glad that removing the 3D has given you most of the routes. The rest I expect are going to be disconnected portions of the network. Let me know if you are not able to find the root cause for them. 

As far as the 3D, I just looked at the line feature class properties and realized it was Z enabled, so used the Editor to examine the 3D sketch properties and see the 3D vertices.

Regards,

Jay Sandhu

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