topic Re: Error: No solution found in ArcGIS Network Analyst Questions

Error: No solution found

KenBurton — Fri, 24 Jun 2011 15:34:46 GMT

Apologies for the simplest of questions, I am very new to networks.

I created a very simple road network. There were errors creating the network, they were all from zero length features in the source data. I think I understand those.

What I can't figure out is when I try to create a route from two graphic pics, I have some intersections that it can't seem to route through. I get a message 'Warning: No route from location 'Graphic Pick1' to location 'Graphic Pick 2'. Error: No solution found.

I can find the specific intersection and turn that it fails on. I just can't see a problem with it. I think they are joined, because I can create map topology for that layer and select that node, having the arcs that touch it rubber band around when I move the node. I assume that means it is physically connected.

Any advice on what to look for would be greatly appreciated.

Also, any resources you know of to learn this stuff, beyond the ESRI help and tuturials, I would appreciate learning about. I don't know where to turn for more info on this topic.

Thanks a bunch.

Ken Burton
US Forest Service

Re: Error: No solution found

KenBurton — Fri, 24 Jun 2011 16:00:52 GMT

I knew all I would have to do was post the question and I would stumble into the answer.

My problem was the 'Connectivity Policy' When I changed it from End to Any Vertex, then the other roads became available to the solution. The clue was when I realized the routes only worked if they were connected at the ends, not in the middle.

Re: Error: No solution found

JoeBorgione — Fri, 24 Jun 2011 16:52:16 GMT

I knew all I would have to do was post the question and I would stumble into the answer.

My problem was the 'Connectivity Policy' When I changed it from End to Any Vertex, then the other roads became available to the solution. The clue was when I realized the routes only worked if they were connected at the ends, not in the middle.

Be careful with vertex connectivity; you may find yourself touting from an over pass to the freeway below....

Re: Error: No solution found

KenBurton — Fri, 24 Jun 2011 18:36:15 GMT

Thanks for the advice, Joe. In this case, the road data is from a national forest, where the road system, and network model, is very simple. In short, I know of no case where there is a bridge crossing another road. Also, if you ignore campground loops, there are no one way roads, and for the most part, no stoplights and very few stopsigns.

At this point, we are just looking to answer some very simple connectivity questions. However, we are likely going to look to integrate forest roads into a larger network of roads. For the moment, I am getting my feet wet in this extension, with the idea that sometime soon, I will need to understand much more than I currently do.

Any ideas for where to go to get smarter on this topic?