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I am trying to digitized the shape file data (attached) that i downloaded from geofabrik, to new roads in my region.

The network anaylst does not work beyond rounds abouts, that I create new ones. It solves the route till round about see pic 1, but beoyond that it fails. and gives me error.

Warning: No route from location "Graphic Pick 1" to location "Graphic Pick 2". Error: No solution found.

when it works

when it gives error

Roundabout in editor mode

then i removed the round about from same position, it work, so something wrong with round about, can anybody help.

roundabout removed

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I've done some testing and I think there are a couple of issues at play here.

Based on your third image it appears the roundabout is a single line that starts and ends at the same point (self connecting/crossing). Each leg of the roundabout should be split to its own segment to provide a distinct network edge. If you create the roundabout as a single line where the first and last vertex/node are at the same point, one of two things will happen depending on how the network was set up (this can be changed by editing the network dataset properties).

  1. The connectivity policy for the street layer is set to End only: If your first/last roundabout point happens to also be an intersection with one of the legs, you can get from that leg onto the roundabout, but not off because a junction can only occur at a line endpoint (aka node, or first/last vertex).
  2. The connectivity policy for the street layer is set to Any Vertex: Junctions can now occur at any vertex, and routes can be found around the line. However, no network edge will be created between the second-to-last vertex and the first/last node depending on how other lines intersect the roundabout.

This network connectivity policy is easiest demonstrated by creating a T intersection. Create a line with three vertices, then a perpendicular line with two - one of which snaps to the middle vertex of the first line. Now create your start point on one leg of the T and your stop on another. In case 1 above, the route will fail with that error message. In case 2 the route will succeed. I can't really explain why your one pre-existing roundabout is functioning, but I cannot tell how it was drawn (ie where the nodes are or if there is a network edge all the way around).

You may also need to modify (or model in the first place) one-way and turn restrictions to ensure correct flow onto, around, and off the roundabout. Your first image shows an invalid route based on the background map arrows. Note that the network must be rebuilt any time the underlying layer is changed.

It may help to turn on the network junctions and edge layers, then use the Network Identify tool to examine the pieces. When you click on a junction or edge, it will tell you which other edges or junction are adjacent to the selected (thus you can see what is and isn't connected).

  • Dear Chris, I tried, I already gave it a try but still it didnt work. Pictures. I constructed the roundabout from separate lines but it still failed, I did put the restrictions, I have also attached the picture from original shp file of roundabout, which appears to be the single line and works flawlessly. – Mike Kevinire Sep 8 '14 at 4:37
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    @MikeKevinire By separate lines I mean from line intersection to line intersection, not necessarily they need to all be two-point lines. And it's more the resulting edges that need to be, at least according to the working networks I have on hand. Did you rebuild the network after making edits to the streets layer? Have you turned on the junction layer to make sure there are network junctions occurring around the roundabout? I assume you're using snapping to make the edits? Are you running any topology checks? Would it be possible to post a portion of the streets with the working and not areas? – Chris W Sep 8 '14 at 20:38

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