Working with
Existing Address
Information
O
ften the information you want to use in your examples is based on
your own knowledge and discovery of suitable latitude/longitude
points for the information that you want to display. There are
times, however, when you already have address information and want to
take that address and convert it into the latitude and longitude data required
by Google Maps for creating points and polylines. For this, the method you
require is called geocoding. This chapter examines the role of geocoding, how
to use geocoder services, and how to update your existing databases with
location information so that you can use the data in your Google Maps
applications.Looking Up Geocode Information
Geocoding is the process of matching up an address, Zip/postal code,
or city with the coordinates required to locate that place on a map. The
geocoding system required depends on the information you require and the
location of the original address. Within Google Maps you are looking for
latitude and longitude information, and this is the most prolific of the ser-
vices available.Data about U.S. addresses is the easiest to look up, because more services
provide the U.S.-based information than information for other countries.
The situation is changing rapidly, and the services available for looking
up information in a range of different countries and through a variety of
methods are constantly expanding.The basic methods of looking up information remain fairly constant. You
must connect to a specific service, supply the information about the address
that you have, and hope to get a response back. Different geocoding services
expose their services in different ways. Some use web services, some use
simple URL-based interfaces, and some are even available “offline” as part
of a separate downloadable package.̨Use a geocoder
̨Look up U.S.
information̨Look up global
informationchapter
in this chapter