I want to better understand what is required in order to implement a geo-spatial (aka proximity) search. I'd appreciate clarification on the following:
Beyond the latitude & longitude for corresponding zip codes, what if anything, is required?
Can anyone recommend any resources (books, websites, etc.) for understanding the formulas that can be used to calculate proximity such as: Haversine, Vincenty, Spherical?
How easy and effective are Mysql's tools for implementing proximity searches?
Does Google Maps have an API for proximity searches? For example if I provide, a zip code can it return zip codes within a set radius? I searched the Google Maps website but found nothing of the sort.
Thanks.