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
MelindaMorang
Esri Regular Contributor

My guess is that something is disconnected in your network.  Try using the Network Identify tool on the Network Analyst toolbar.  With this tool activated, you can click on a road segment, and it will show you which other network edges and junctions it's connected to. You can use this to diagnose connectivity problems.  The tool will also tell you the value of various restrictions and impedance attributes, so you should check those and make sure they are correct as well.

If you make any edits to your network dataset, don't forget to run Build Network before running an analysis

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JeremyScott
New Contributor II

Hey, Melinda.

Thank you for getting back to me. I have used the Network Identify tool on

all segments between the two stops and don't see anything that appears to

be out of order (I am not really sure what I am looking for). Any other

suggestions? I was able to connect stop 25 with stop 27 by allowing the

reordering of stops (I can't do this in the final analysis) and that

worked, but still left out stop 26.

Sincerely,

Jeremy

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MelindaMorang
Esri Regular Contributor

It still smells like a connectivity issue to me.  Here is some conceptual documentation explaining the various types of connectivity in case you want to dig into it: Understanding connectivity—Help | Documentation 

If you are able to share your data (both network dataset and Route layer), I could take a look.

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JaySandhu
Esri Regular Contributor

You can also do a service area (with the lines option, not polygons) from one of your stops and see if you can reach the second stop. It might show the connectivity problem area.

Jay Sandhu

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JeremyScott
New Contributor II

Jay,

How do I fix this issue on a global level? I was able to fix the issue with

the previous example, but now running into it in other places. As far as I

can tell, there don't appear to be any network issues (I disconnected and

reconnected each of the segments at the intersection in question). The

screenshot below shows the issue for the road segments in light blue.

Thanks,

Jeremy

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JaySandhu
Esri Regular Contributor

The screen shot in question shows the blue lines connecting to the purple lines at one location. Is the purple line split at that location if you are using End point connectivity? If it is not split, is there a vertex there for the blue lines to connect IF use Any Vertex connectivity? If you do not have it split AND you do not have a vertex on it for any vertex connectivity then you may want to run the GP tool Integrate to create those vertices. If you do use Integrate, make sure you use it on a copy of the data as it will modify the data.

Integrate—Data Management toolbox | Documentation 

Jay Sandhu

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JeremyScott
New Contributor II

Jay,

Thank you for responding. The purple line does split where the blue line

meets. At that intersection, there are three separate lines meeting at the

same vertex. So, it seems there is an intersection there and the

directionality of all segments should allow a traversal from the blue line

to the purple line.

Thanks,

Jeremy

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JaySandhu
Esri Regular Contributor

Can you do a service area lines from a location on the blue lines and does it get stopped at the junction where it connects to purple lines? If yes, then there is some issue in the connectivity there. Perhaps the blue line is not snapped to the purple lines. Or it could be a restriction or negative attribute value that prevents the path.

It is hard to "debug" without looking at the data. If the data is small (or make a subset), perhaps you can package up the data with a couple of locations that do not route and send/post it.

Jay Sandhu

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JeremyScott
New Contributor II

Jay,

Here is the network dataset as well as a subset of the stop locations. The

two stop locations I know are causing problems are OBJECTID 49 and 52. When

I add the Stop Locations, the stop sequence field is defined as STOP SEQ

and the Route Name field I use us RUN BEGIN TIME. This should give you 4

routes, of which only two actually have a solution.

I really appreciate any help you may be able to provide. Let me know if you

have any questions or need anything else.

Sincerely,

Jeremy

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