Distance to nearest store

nop has asked for the wisdom of the Perl Monks concerning the following question:

Hi. I want to find, for each US 5 digit zipcode, the distance to the nearest store run by one of our competitors. I can determine a list of competitor zips by using the store locator on their site. I also need a good source for the latitude and longitude of (the centroid, I guess) each zipcode, as well as a function to get the distance (great circle, I guess) between two points specified in latitude and longitude, as well as reasonable approach to find the closest zip to each zip (as there are 30 or 40K valid zipcodes).

This doesn't need to run in real time -- it is not a web app -- but I do need to refresh the whole process every few months.

Any suggestions from the Monks? Any useful CPAN modules I should be considering? Any good sources of zipcode data in the public domain?

Comment on Distance to nearest store

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Re: Distance to nearest store by lhoward (Vicar) on Jan 03, 2001 at 23:56 UTC
This has been addressed before on perlmonks in some depth: Searching by zip code Determining the distance from one zip code to another	[reply]
(Ovid) Re: Distance to nearest store by Ovid (Cardinal) on Jan 03, 2001 at 23:47 UTC
You may find this link useful. It has links to public domain zip code data and even a module that has some of the functionality that you are searching for. Cheers, Ovid Join the Perlmonks Setiathome Group or just click on the the link and check out our stats.	[reply]
Re: Distance to nearest store by lemming (Priest) on Jan 03, 2001 at 23:41 UTC
jcwren does a nice job with his monk map locator. Check out his page. Though I don't think he uses the great circle technique.	[reply]