Geocoding with PHP and the Google Maps API
Beginning with Google Maps
While we are not specifically dealing with the display of maps on our web sites in this article, we still need to be familiar with the Google Maps API. All documentation for the API can be found at http://code.google.com/apis/maps/index.html.
The first thing that you must do is to create an API key for your web site. This is used to identify all requests to the API. You can receive a free key by agreeing to the terms and entering your web site URL at http://code.google.com/apis/maps/signup.html.
At time of writing this article, the limit on geocoder requests is 15,000 per day, which will hopefully be sufficient for your needs. As mentioned later in this article, you are encouraged to cache geocoder data in your own application wherever possible.
Once you have an API key then you are able to access the geocoder. In the rest of this article we will cover how to use the geocoder, which is based on the documentation at http://code.google.com/apis/maps/documentation/services.html#Geocoding_Direct.