1

This question already has an answer here:

Although reasonably experienced with ArcGIS I am a bit of a newbie with Network analyst. I have a situation in which things work Ok with the tutorial data but not with mine!

I am trying to determine an 8km road distance from a set of hospitals in East Africa. I have some roads data that I can build into a network. As far as I can see there is full connectivity. If I work using detailed polygons (which is what I want) I get this.

net2

So the "service area does not go along roads A,B and C, which I would expect it to. and how on earth does it think I am going to get to Point D!!.

Using generalised polygons I get this:

net2

Now I have lost the slightly anomalous point D, but the services area still does not traverse roads A and B.

I am using ArcGIS 10.2 for Desktop.

marked as duplicate by underdark Dec 4 '14 at 21:36

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

  • I find the images very small and hard to read. Also it appears they are hosted off-site - it's better to use the picture icon above the editing box to embed your images so that a copy is permanently included should you delete it or it be otherwise removed from flickr. Regarding D and the detailed polygons, you may want to take a look at this question. Per the answer below, it doesn't look like A and B are connected to the network or there is a barrier in place. Or a connectivity policy issue. – Chris W Dec 1 '14 at 21:39
  • OK, it looks like it was connectivity policy. Thanks for that and the tips on images – Rob Corner Dec 2 '14 at 0:18
2

With respect to A,B,C:

  1. try checking your network with the topology tool, every "line" must be connected to an other line by a "point"(http://resources.arcgis.com/en/help/main/10.1/index.html#//004700000009000000). Sometimes I get the same problem, you can solve it by connecting the errors or - sometimes it´s much faster - edit a new line.

  2. If you use barriers or other rules, then in OSM for example there are point barriers, like gates, or line rules, like private roads. You can´t travel them - if you use rules like that.

With respect to D, it looks like wrong "interpolation" of the GIS, also get sometimes errors like this.

Not the answer you're looking for? Browse other questions tagged or ask your own question.