Location Allocation (minimize facilities) providing strange results

Discussion created by justinhampton81 on Feb 15, 2012
Latest reply on Feb 16, 2012 by doug_sterling-esristaff
I am trying to identify the minimum number of stations using the Location-Allocation minimize stations function.  I have 710 potential locations and roughly 40,000 demand points.  Based on the street speed limits, and the size of the area, I believe that all of the demand points could be reached by 7-9 stations within 4 minutes, and 4-5 stations in 8 minutes (just
eyeballing it based on previous service area maps). 

However, when I run the minimize facilities problem type using a 4 minute impedance in the location allocation tool, the results show approximately 21 stations, and many are within a thousand feet of each other.  There are only two settings: the impedance cut-off  (I'm using 4) and the impedance transformation (I'm using linear), am I doing this incorrectly? 

Any advice would be much appreciated, I've been working on this for a couple of days with much aggravation.