Site location anlaysis - national scale

[MarkGuagliardo]

For sake of simplicity consider this problem limited to the lower 48 U.S. states.

We have 8.5 million geocoded client residential locations and 1,000 sites of service. For each client we have estimated drive time and drive distance to the nearest site of service. We want to identify the best places in the country to place new service locations. How should we go about it?

Here are some working assumptions, though we invite your input on these as well:

1. We have no rock solid model for how attractiveness of service decays with increasing drive time or drive distance. There is an industry standard that all clients located <= 30 minutes from an existing site of service are considered to have adequate vehicular access, and all others are considered not to have adequate access. Therefore a cluster of ???unserved??? clients centered 60 minutes from an existing site is equally as interesting as one that is 240 minutes from an existing site.

2. All clients are of equal interest, save for their distance from existing sites.

We do not know how many new sites can be funded. Therefore we would like to rank the identified hotspots or clusters of need.

We would prefer to work with the point locations of clients rather than aggregated statistics in administrative bordered areas. However we will consider polygon analysis if the suggested unit of analysis is granular enough.

We will consider statistical sampling but would need guidance on how to go about it.

We are working with ArcGIS 10.x. We have Spatial Analyst, Network Analyst, Geostatistical Analyst and 3D Analyst, as well as StreetMap Premium. We are working on a 16-core server and we don't mind if processes take a few days (or more) to run.

We also have SAS software at our disposal if necessary.

Thanks in advance.

[LaurenRosenshein]

Hi Mark,

This sounds like a very interesting analysis!  One possible way to think about this would be to do a hot spot analysis of the drive times to the nearest site of service.  This would give you an idea of where you have hot spots of customers with very high drive-times to sites of service.  A good place to start.  To learn more about hot spot analysis inside of ArcGIS you may want to check out the short videos and tutorials available here:  http://esriurl.com/spatialstats.  As far as ranking the hot spots, one possibility may be to rank them by the number of features involved?  A hot spot of 10 customers with long drive-times to sites may be less important than a hot spot with 1000 customers with long drive-times.

You may also want to think about posting this question in the Network Analyst forum because, as with any complex problem/question, there are always many ways to go about it, and probably the best way to do it is a combination of several methods including some network analysis/optimization analysis.

Hope this helps.

Lauren Rosenshein
Geoprocessing Product Engineer

[RobertBurke]

Hi Mark,

You didn't mention having Esri's Business Analyst, but that is exactly what that product/extension is used for.  It has tools to help define the site trade areas and determine if any are canabalizing each other. Then there are tools to rank potential sites.  You have 50 potential sites, rank them in order based on attributes of your best performing sites.  I teach the two day Business Analyst class so I could go on and on.

Since you may not have Business Analyst, there is a simple poor-man's technique you might try.

Take your sites and create Theissen polygons, you will find the tool in ArcToolbox. It will create equal competition polygons around all the sites.   You might try this regionally instead of nationwide at first.  The polygons will form a honeycomb like pattern that looks cool.  But what you can do now is look at where 3 or 4 polygons meet.  Say you find a point where 4 polygon corners come together.  Well that spot is really far from 4 of your sites.  It could be a potential spot for a new site since it is so far from all the others.

Problems though.  That spot could be in the middle of a water body or mountain range were there are no people.  However if it is in the middle of a highly populated area, then you might look at that area more  to see if it also has the demographic mix of your best customers.

If you had Business Analyst you could look at consumer spending data for your site's product mix to then also see if that area is spending on your products already.

And of course what about your competition and their locations.

Should be interesting.

Rob