Introduction

One of the unique capabilities of mobile Web access is the ability it affords the user to tailor his or her experience based on physical location. Palm OS Web clipping supports this through U.S. Postal Service Zone Improvement Plan (ZIP) Code information that can be provided for the device.

Each Palm VII device communicates with Palm.Net via a BellSouth Mobitex base station. The wireless system keeps track of the base station with which a Palm VII device is communicating, and also the ZIP Code of each base station. By correlation, the wireless system can determine the ZIP Code of a Palm VII device.

Using ZIP Code information is a way to make your applications position-sensitive. You will find that despite some technical challenges, ZIP Code interpretation can greatly improve the user experience. Technical challenges include the need to turn ZIP Codes into coordinates and searching through a database to find coordinate-based information (for example, the closest address). It can be quite complicated, but the challenges are typically justified by the outcome.

Already, many useful position-based systems exist. Weather applications use your local ZIP Code to tell you about conditions nearby. Store and bank locators can tell you the closest branch position. News sites can tailor the coverage to include both local and national stories.

In this chapter, you will learn how to make your WCA position-sensitive, including both obtaining and processing position information. You will learn how to find a Palm VII device s ZIP Code and how to map...