2 Replies Latest reply on Mar 24, 2014 9:08 AM by bking-esristaff

    Network Analyst-counting intersections

      I have ben tasked with an assignment to plan a evacuation route out of a neighborhood that has only 2 exit points. I am trying to make a map that will code a series of streets by the number of turns an evacuee will have to make to get to one of the 2 designated exits. I have made this map by hand for a small neighborhood but now I have to do it for a much larger street network. I don't know if there is a way to get NetWork Analyst to count turns. I can't use nodes because it will include the end of the streets and intersections don't work because going straight is an option. I think closest facility is the way to go but I don't don't know enough about this extension to continue. Any thoughts?
        • Re: Network Analyst-counting intersections
          1. Open (or create a new) network dataset (ND) in ArcCatalog
          2. Riht-Click / Properties / Attributes / Add (when creating a new ND, the default settings will automatically generate a length attribute)
          3. Make it a Cost Attribute / Unknown Units / Integer
          4. Go to Evaluators / Default Values
          5. Element "Turn" / Type "VB Script" / Default --Click Evaluator Properties 5. Enter the following VB script: turnscount = 0 a = Turn.Angle If a >= 20 And a<= 340 Then turnscount = 1 Else turnscount = 0 End If Value= turnscount
          This script will count every turn that is more than 20deg sharp as a turn.

          For counting junctions, do another attribute, and in Default Values, click "Junction", Default=1 This will count every junction as 1
          • Re: Network Analyst-counting intersections
            Andres - Thanks for the reply.

            sstone13 - If you are looking for more info, you might try posting to the forum link below, as the Network Analyst extension is not part of the Esri Defense Mapping solution.  Best of Luck.

            Network-Analyst Forum: http://forums.arcgis.com/forums/102-Network-Analyst