iPhone SDK 3 Programming: Advanced Mobile Development for Apple iPhone and iPod touch

Chapter 13. Location Awareness

This chapter addresses the topic of Location Awareness. First, Section 13.1 covers the Core Location framework and how to use it to build location-aware applications. After that, Section 13.2 discusses a simple location-aware application. Next, Section 13.3 covers the topic of geocoding. In that section, you learn how to translate postal addresses into geographical locations. In Section 13.4, you learn how to sample movement of the device and display that information on maps. After that, Section 13.5 discusses how to relate zip codes to geographical information. In that section, you also learn the actual formula that implements the distance between two locations. Next, Section 13.6 shows you how to utilize the Map Kit API to add an interactive map to your view hierarchy. Finally, we summarize the chapter in Section 13.7.

The Core Location Framework

The second generation of the iPhone (iPhone 3G) is equipped with a Global Positioning System (GPS) chip. GPS utilizes three or four satellites to triangulate the position of a point on earth. The accuracy of the point's position using this technique ranges from 5 to 40 meters.

The first generation of the iPhone uses non-GPS techniques for identifying the location of the device. Non-GPS techniques such as Cell-Identification, Time-of-Arrival (TOA) and Enhanced Observed Time Difference (E-OTD) can be used in conjunction with Wi-Fi and Bluetooth to provide a reasonable substitute for the lack of a GPS chip [3]. ...