Hi guys,

I need a zip code radius finder and calculator in my asp.net application where i will provide a zip code, a distance (in miles) and should get a list of zip codes which are the specified miles away from the specified zip code. A site
http://www.zip-codes.com/zip-code-radius-finder.asp provides the similar feature to its general users but i need this thing in the background (in the form of xml, delimited text etc.) so that i will go ahead and show the rental properties in my database matching those zip codes. Is there any site/service available on the net who can provides this service via the background code (preferably free of cost)?


thanks,


baburman

BaburMan

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BaburMan

For free, no you are not going to find a service like this I don't think. When I did this in the past I purchased a database of Zip Codes (approx. $200 USD) and then wrote the mathmatic equations to caluclate distance based upon a given zip codes latitude and longitude. (Obviously a Zip Code does not represent a specific physical location like a Stree Address)

Google might help you more.

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Ok for now i managed to get this from http://www.zip-codes.com/zip-code-radius-finder.asp using HttpWebRequest and HttpWebResponse objects and posting a request and parsing the received stream for the zip code. Though it servers the purpose but i still need a reliable solution.



thanks

BaburMan

Well I guess what is your definition by reliable. For example, the process that I wrote, providing the zip code I live in and the zip code of a neighboring town would return 7 miles, however, Mapquest would return 10.0 miles. Here is the problem: MapQuest calculations work against GeoSpacial data (roads, interstates, etc) my process applied a Great circle theory to an origin latitude and longitude against a destination latitude and longitude resulting in a straight line. Since the shortest distance between 2 points is a straight line my calculations are obviously going to return a shorter distance than that returned from a Mapping service that takes into account all things one might deal with when they travel.

So how reliable do you need this?

================================================== =========
Read this if you want to know how to get a correct reply for your question:
http://www.catb.org/~esr/faqs/smart-questions.html
================================================== =========
.: Wrox Technical Editor :.
Wrox Books 24 x 7
================================================== =========

In fact i do not mean 'reliable' this way. What i think is that if the site that i am getting the info from by parsing its data - changes its rendering html at any time in future so that my parsing logic becomes obsolete. However for a service who is bound to provide such data as a service (like in xml using a backend interface) will never change its provided data format for its clients.



BaburMan