Network Analyst Question

PeteLarson — Wed, 24 Nov 2010 17:18:39 GMT

Hello,

I have 2 point data sets and a road network. I have a set of households and a set of health facilities. I want to calculate the distance along the road network from the households to the nearest health facility.

I can use Network Analyst to get the distance along the road, but the travel distance from the household to the road and from the road to the facility is left out. So what I get is a number of strange distances.

Is there anyway to coax Network Analyst into giving me the total distance?

Thanks,

Pete

Re: Network Analyst Question

JaySandhu — Wed, 24 Nov 2010 18:11:47 GMT

Network Analyst solves on a network. It does not know about "off road". So by default it will give you a total path length based on the network. However you can add in an extra delay at the start and end location to the total path length. Say you are solving on "meters" and you also happen to know how many meters away the start and end locations are from the closest road, then when you load in the stops, you can map in this information to the "Attr_meters" field. Now when you solve, it will add the additional information from the start and end location to the overall path length.

You can read more about the Attr_[Impedance] here:
http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//004700000045000000.htm

So then the question is how far away are the stops from the network. You will have to run some tool to figure that out in the units of your impedance attribute. Couple of tools you could use are the Near tool and the CalcualteLocations tool which adds an additional field with the distance to the snapped location on the network. You may have to change the units of the distance to match your impedance units.

Regards,
Jay Sandhu

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