topic Re: Overlapping routes in Closest Feauture in ArcGIS Network Analyst Questions

Overlapping routes in Closest Feauture

johnpaulou — Wed, 05 Jan 2011 20:28:48 GMT

Hello everybody. My first post in forum. I am a student network engineering and my diploma thesis needs arcgis. let me explain you in a few lines.

I have some building blocks (~400 blocks) [polygons] and street segments (~1000) [polylines] around them. I take random points (~7000) in the blocks and with Network Analyst and Closest Feauture I create new network dataset and take the shortest paths from a central point (Facility) to the 7000 points (Incidents). As a result 7000 routes [polylineM] are generated. My question is how can I find how many routes cross every street segment.

Here is what I' ve done: I make dissolve for the routes (with no fields and not check the button create multipart feautures) and I get a dissolve_routes [polylineM] shape with mutual street segments (~650 segs) but without counting the routes as I wanted.

So, later I made Spatial Join the dissolve_routes (buffer of dissolve_routes) with all the routes to take the join_count field. However it never finishes (I left it for a day and no result). I also tried to take the spatial joins of the routes and the dissolve_routes_points (central x/y points of them) but the result was the same. Any ideas..?

One idea was to reduse my elements, but I want to have large regions with points up to ~50.000.
Any ideas would be helpfull. Thanks, John.

Re: Overlapping routes in Closest Feauture

JaySandhu — Fri, 07 Jan 2011 14:49:22 GMT

When you solve the closest facility (or route), the resulting output contains one line feature per route and do not contain the individual edges that made up that route. However, that information is available in memory in form of a traversal result and can be accessed to turned into line features. Once you have that, you can simply summerize on the source object id and find out how many times each edge has been traversed. You can use the following resource to add the traversal result right after you solve the CF to the ArcMap TOC:

http://resources.arcgis.com/gallery/file/arcobjects-net-api/details?entryID=C8A2186E-1422-2418-3494-48812C8DB8DE

Jay Sandhu

Re: Overlapping routes in Closest Feauture

johnpaulou — Sat, 08 Jan 2011 23:02:59 GMT

Thanks for the reply. I have arcgis 9.3. I saw that addin can be installed on version 10. Any tip?

Re: Overlapping routes in Closest Feauture

JaySandhu — Mon, 10 Jan 2011 14:03:08 GMT

If you have 9.3, then you can use the following VBA and run it after you solve the Closest Facility. It will add two new feature classes representing the lines and junctions that were traversed.
Regards,
Jay Sandhu

Public Sub AddNATraversalResultToArcMap()
Dim pMxDoc As IMxDocument
Dim pNetworkAnalystExtension As INetworkAnalystExtension
Dim pNALayer As INALayer
Dim pFLayer As IFeatureLayer
Dim pTraversalResultQuery As INATraversalResultQuery
Dim pNATraversalResultEdit As INATraversalResultEdit

Set pMxDoc = ThisDocument
Set pNetworkAnalystExtension = Application.FindExtensionByName("Network Analyst")
Set pNALayer = pNetworkAnalystExtension.NAWindow.ActiveAnalysis
Set pTraversalResultQuery = pNALayer.Context.Result
Set pNATraversalResultEdit = pTraversalResultQuery

'Infer Geometry
pNATraversalResultEdit.InferGeometry "", Nothing, New CancelTracker

'Get the Edges and add as a layer
Set pFLayer = New FeatureLayer
Set pFLayer.FeatureClass = pTraversalResultQuery.FeatureClass(esriNETEdge)
pFLayer.Name = pFLayer.FeatureClass.AliasName
pMxDoc.FocusMap.AddLayer pFLayer

'Get the Junctions and add as a layer
Set pFLayer = New FeatureLayer
Set pFLayer.FeatureClass = pTraversalResultQuery.FeatureClass(esriNETJunction)
pFLayer.Name = pFLayer.FeatureClass.AliasName
pMxDoc.FocusMap.AddLayer pFLayer
End Sub

Re: Overlapping routes in Closest Feauture

johnpaulou — Tue, 11 Jan 2011 18:55:27 GMT

After copy / paste your code in Visual Basic Editor and run it I get Edges and Junctions layers but when I open the attributes tables I get no objects. Is there sth on your code I had to change? I am totally newbie at VBA..

Re: Overlapping routes in Closest Feauture

JaySandhu — Tue, 11 Jan 2011 22:48:04 GMT

Did you solve the closest facility just before running the VBA? i.e. if it is an existing map document or layer that has been solved in a previous ArcMap session then there will be no traversal results still in memory for the VBA to access.

Jay Sandhu

Re: Overlapping routes in Closest Feauture

johnpaulou — Wed, 12 Jan 2011 10:36:49 GMT

You re right. I had the routes from previous run. thanks.