# Find closest x number of points

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03-22-2016 11:14 AM
Occasional Contributor

I am trying to find a way to equally distribute 10,000 points amongst 26 fire stations. These points are locations of fire inspections. If there are 26 stations, how would I equally distribute 10,000 fire inspections so that each station has an equal number of inspections to perform?

We have tried using closest facility, but it does not equally distribute the number of points per station.

We almost need to iterate through each station. Find closest 385 points for station 1, remove those 385 inspection points from the incidents layer, and start back at the beginning for station 2, look for it's closest 385 points, remove those 385 inspection points from the incidents layer....etc.

Has anyone ran into this before?

Thanks!

I am using ArcGIS 10.3.1- ArcInfo License

1 Solution

Accepted Solutions
Esri Regular Contributor

Hello, Robert.  This actually sounds like a problem you could solve with Location-Allocation.  You would just need to set the all the fire stations as "required" facilities.  You could further limit the results by assigning a weight to each inspection (even if it's just 1) and a capacity to each fire station (the max number of inspections it's allowed to do).

7 Replies
MVP Frequent Contributor

Question - do the inspections need to be determined based on the road network?  I ask as there are several processes for allocation, but they commonly do not take into account a street network.  Since you tagged this with Network Analyst, I assume you want the network taken into account, but just want to verify that.

Chris Donohue, GISP

Occasional Contributor

Chris,

Thanks for the reply! Yes we would like to use our road network. My apologies for not clarifying!

Occasional Contributor

We are however, open to non-network processes if it is difficult to use network analyst!

MVP Honored Contributor

I don't have the answer, but how skewed is the result if you simply allocate each inspection to the nearest station? The problem with iterating by station is that the first station will be very happy (they got all the most convenient 385 inspections), the second station will be happy but less so because some of their most convenient inspections may have been taken by the first station, same for the third station (which may have lost inspections to the first and second stations), and so on until the 26th station gets the remainder with perhaps some close inspections and probably a bunch all the way across town.

Occasional Contributor

Thanks Darren. I did not think about that....gives us more to think about...hmm

Esri Regular Contributor

Hello, Robert.  This actually sounds like a problem you could solve with Location-Allocation.  You would just need to set the all the fire stations as "required" facilities.  You could further limit the results by assigning a weight to each inspection (even if it's just 1) and a capacity to each fire station (the max number of inspections it's allowed to do).

Occasional Contributor

Thanks Melinda! This helped me to find this answer to another question on Geonet:

This expands on your answer a bit and tells us to set a capacity with the "Maximize Capacitated Coverage" option.

Thanks again all!