Trouble with Service Area polygon size

1256
2
Jump to solution
08-29-2012 01:00 AM
Highlighted
New Contributor
Hello,

I've had a look at previous threads discussing this issue but the solutions suggested on those threads have not seemed to help with the problem I have.

I have set the Service Area Polygons to distances of 5, 10 and 20 miles from my locations (using the equivalent number of meters - 8047m, 16093m, 32187m) but the result is confusing. As you can see in the picture there is very little difference between the 5mile and 10mile polygon in the North-East direction despite roads existing there.  Also I measured the 20 mile polygon distance using the green route (applied to the same network) but the route measures 12.5miles yet reaches the edge of the 20mile polygon boundary?

[ATTACH=CONFIG]17312[/ATTACH]

Can anyone explain why this is? In previous threads creating a route on the network was suggested to identify broken links but in this case the route is fine but the service area is incorrect?

Thanks for your time,

Steve.
Tags (2)
Reply
0 Kudos
1 Solution

Accepted Solutions
Highlighted
Esri Regular Contributor
Most likely there is a high cost street in that area. Bring up the properties of the service area layer and turn on the Lines and have it split lines at breaks, re-solve. Now examine the lines in the area of interest to see what is the cost assigned to the edges (from/to cummulative costs). That should point to the underlying network costs causing a distortion in the polygon.
Jay Sandhu

View solution in original post

Reply
0 Kudos
2 Replies
Highlighted
Esri Regular Contributor
Most likely there is a high cost street in that area. Bring up the properties of the service area layer and turn on the Lines and have it split lines at breaks, re-solve. Now examine the lines in the area of interest to see what is the cost assigned to the edges (from/to cummulative costs). That should point to the underlying network costs causing a distortion in the polygon.
Jay Sandhu

View solution in original post

Reply
0 Kudos
Highlighted
New Contributor
Most likely there is a high cost street in that area. Bring up the properties of the service area layer and turn on the Lines and have it split lines at breaks, re-solve. Now examine the lines in the area of interest to see what is the cost assigned to the edges (from/to cummulative costs). That should point to the underlying network costs causing a distortion in the polygon.
Jay Sandhu


Thanks very much for your help Jay. When using the line generation it prompted me to turn off the hierarchy I was using (I numbered motorways, A roads, B roads and minor roads 1-4) and the polygons look correct now. As I'm only interested really in distance, not time I'll not use the hierarchy in future.

Thanks again,

Steve.
Reply
0 Kudos