different service area polygons generated between v10.0 and v10.1???

[HeatherJaramillo]

I created a service area polygon in 10.0, and now using the exact same network in 10.1 (no edits have been made since) and the same settings (I use the default for everything except I choose 4 minutes as my break), I'm getting slightly different results.

Is this happening to anybody else?

[JoeBorgione]

The illustration provided only shows one; where is the difference?

[HeatherJaramillo]

The thicker black boundary is the result from v10.0 and the green poly is the result from v10.1

[JoeBorgione]

That being the case, the only significant difference I notice is to the lower right side of you image.  Can that be explained with the cut off time?

[HeatherJaramillo]

That being the case, the only significant difference I notice is to the lower right side of you image.  Can that be explained with the cut off time?

They are both using a 4 minute cut off time.  I agree, it's really not all that different.  I use these areas for a slew of other calculations and I was asked to run the same calculations with a 6 minute and an 8 minute variable, so when I can't duplicate the same 4 minute result after upgrading it's very frustrating!

[JoeBorgione]

Perhaps Jay, Patrick or one of the other ESRI NA guys can weigh in here....

[JaySandhu]

Is there hierarchy in the network and is that on by default when you do the service area. (I think not looking at the picture but just want to be sure).

Can you turn on the Line generation and re-solve for both 10 and 10.1 and check if the lines are being generated in the the area the polygon was covering in 10?

Jay Sandhu

[HeatherJaramillo]

Is there hierarchy in the network and is that on by default when you do the service area. (I think not looking at the picture but just want to be sure).

Can you turn on the Line generation and re-solve for both 10 and 10.1 and check if the lines are being generated in the the area the polygon was covering in 10?

Jay Sandhu

There is no hierarchy used.

Here are 2 screen shots, one from version 10.0 sp5, and the other from 10.1 sp1.
They are both using the exact same street network and facility location. All other variables are set to the default with the break set to 4 minutes.

The lines generated are identical, the polygons generated are different.

[JaySandhu]

There may have been some changes/bug fixes to the service area generalized method that is causing the changes you see. The polygon generation is very sensitive to slight changes in tolerances we use. Also, the generalized method does not guarantee that all edges that were not traversed will be excluded (i.e., it does not have holes for unreachable streets). You can try the detailed method and that will guarantee correctness in terms of streets that were traversed and those that were not traversed.

Jay Sandhu