Re: Zipcode based query, how?

burzin@twinsun.com (Burzin Engineer) wrote: >Hello, > I am wondering if anyone has any ideas on zipcode based >approximations for a list of addresses. The idea is that when a >user types his zip, he gets a list of stores that are within a radius >for him. Sounds simple but what happens when your zipcode does not match >exactly? Which zipcode should you go to next? >Seems like their should be a solution for this. Any pointers appreciated. >Thanks. Zip Codes are a poor way to do distance-based searches. Many zip codes gerrymander all over the place--that is, they are irregularly shaped and often have appendages that would thwart most techniques. Also, urban zip codes are densely packed and rural zip codes are not. The Empire State building has its own zip code, as does the Educational Testing Service, but there are zip codes in Wyoming that are probably close to the size of Rhode Island. If you can get zip+4, then there should be a way to get the latitude and longitude values, and then apply a formula for calculating distances between two lat./long. coordinates.