GIS Help: distance calculation based on ZIP Code
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From: ggrothendieck at gmail.com Date: Wed, 8 Dec 2010 10:50:40 -0500 To: lihawaii at gmail.com CC: r-help at r-project.org Subject: Re: [R] GIS Help: distance calculation based on ZIP Code On Wed, Dec 8, 2010 at 10:41 AM, XINLI LI wrote:
Dear R Group Users: If there is a resource or easy way to calculate the distance between zipcodes, for example, if I have the zipcode for 200 patients, and the zipcode of a hospital, how to calculate the travel distance of these individual patient to the hospital based on the zipcode. Your input will be greatly appreciated.
Try the R-Sig-Geo list.
Data sources do come up here a bit so I will comment that you can get line-oriented lists of post office locations and more from the census. The TIGER files would let you find streets etc but are probably too big for hosting yourself. IIRC, I had to cobble together the zipcode locations but the data is available. Probably you need more resolution and other things like traffic data to make a routing decision but I would mention the landmarks DB probably does have hospitals listed. Also, distances are short enough that "as the crow flies" you could probably linearize and use scaled x*x+y*y instead of the spherical stuff. I may have put it up here along with other illustrations of things you can do with public data, http://www.spottext.com/marchywka/distroform.cfm ( I would caution this site is not exactly professional but it may be informative, I am using it for idea testing etc )
-- Statistics & Software Consulting GKX Group, GKX Associates Inc. tel: 1-877-GKX-GROUP email: ggrothendieck at gmail.com
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