Zipcode based search

Question

I want to make a geographical search using US city and state or zip-code and corresponding results will be viewed. In the search we have to mention the radius distance. For example: i would like to search between 25 miles around California.

To do this, what should i do? is there any database containing us city,state,zip, latitude, longitude information?????

Please help me with this asap

with regards Tarek Mahmud Apu

Answer 1

For zipcode-based geolocation, see http://code.google.com/p/zip-code/ for example.

Answer 2

GeoNames

The GeoNames geographical database covers all countries and contains over eight million placenames that are available for download free of charge.

There is also a webservice.

Answer 3

Once you convert your zip code data to longitude and latitude, here are a couple resources for working with the coordinates.

Converting miles to degrees longitude and latitude

Computing distance from longitude and latitude

Answer 4

Free zip code database with lat/long coordinates at:

http://www.populardata.com