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I am running a Salesman analysis and get the following error message:

Terminal at node [1860] cannot be connected to terminal at node [1923]

I have been able to identify one of the nodes by a process of elimination, but is there a way for me to identify node #1860 and #1923 easily and visually?

This relates to my other question Orphan road segments

PolyGeo
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Tim P
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  • Did you run v.net (http://grass.osgeo.org/grass70/manuals/v.net.html) on the network in order to maintain it? – markusN Jul 30 '15 at 10:39
  • Yes. My source data was from OSM. I have (a) snapped it (v.clean.snap), (b) broken it (v.clean.break) and (c) used v.clean.bpol based on another response on this site. I then used network allocation (v.net.alloc) from a single central node connected to the network (v.net connect) so I know all the roads are joined. I then connected my target points to the network and ran the Salesman analysis (and Steiner).

    The Salesman works with a limited data set, but with another set of similar points I get the node errors. This is my problem - how to I identify which nodes are causing the error?

     – Tim P Jul 31 '15 at 13:21
  • Could you make the dataset available? With v.pack (http://grass.osgeo.org/grass70/manuals/v.pack.html) it can be exported losslessly in GRASS vector format. – markusN Jul 31 '15 at 17:52
  • Sure. I have uploaded to Dropbox.https://dl.dropboxusercontent.com/u/12429229/GR_Roads_AllPoints.pack

    Categories 30, 50 and 60 work fine for a Salesman analysis. Categories 10, 20 and 40 cause errors.

    Created using GRASS7.0.1.

     – Tim P Aug 01 '15 at 06:50

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Let me suggest to use the nice vector network analysis tool which you can find in the menu (manual page). It allows you to snap the points to the network (second icon under "Points for analysis") automatically and is really easy to use.

Two screenshots generated based on your data (I created a LatLong location, epsg:4326 for it).

Travelling salesman in GRASS GIS 7: Travelling salesman in GRASS GIS 7

Subnet allocation in GRASS GIS 7: Subnet allocation in GRASS GIS 7

Likewise you can switch to other network analysis methods.

markusN
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  • Hello Markus. Thanks for the response. I see that you added 5 new points for the analysis. What I need to identify is which on my points / nodes are given me the errors (and causing the algorithm to stop), and how to fix this. – Tim P Aug 28 '15 at 11:45
  • Did you process them with the v.net module? – markusN Aug 29 '15 at 08:13