Building a map using Yahoo! Maps or Google Maps requires Latitude and Longitude points. Until Yahoo! released it's GeoCoding APIs getting address latitude and longitude was neither easy or free. At this time Yahoo! allows you to GeoCode 50,000 addresses a day. The code below will call the Yahoo! GeoCoding API using C# and ASP.NET 2.0.

Latitude and Longitude Precision

When supplying Yahoo! with an address, it will try to return the highest level of precision. The returned XML document will tell you how precise the latitude and longitude are. If it can't resolve an address, it will return a warning.

Files Included in Download

* GeoCode.aspx - Form to enter address. Also will display response from Yahoo!.
* GeoCode.aspx.cs - Calls class to make geocoding request.
* GeoAddress.cs - An address class.
* GeoAddressAPI.cs - Class which calls Yahoo! and parses response.
* web.config - Holds application ID required by Yahoo!

GeoCode.zip - Don't forget to enter your application ID at the end of the querystring in the web.config file. This format supports ASP.NET 2.0. If you are running 1.1, you will need to make some minor adjustments to how you store your API url in the web.config file.

Working Demo

GeoCoding C# Yahoo Demo

Labels: API, ASP.NET, Mapping, Yahoo