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 )

--
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email: ggrothendieck at gmail.com