CHAPTER 31
Accessing Location-Based Services
A popular feature on current-era mobile devices is GPS capability, so the device can tell you where you are at any point in time. While the most popular use of GPS service is mapping and directions, there are other things you can do if you know your location. For example, you might set up a dynamic chat application where the people you can chat with are based on physical location, so you're chatting with those you are nearest. Or, you could automatically "geotag" posts to Twitter or similar services. GPS is not the only way a mobile device can identify your location. Alternatives include: •
The European equivalent to GPS, called Galileo, which is still under development at the time of this writing
•
Cell tower triangulation, where your position is determined based on signal strength to nearby cell towers
•
Proximity to public WiFi "hotspots" that have known geographic locations
Android devices may have one or more of these services available to them. You, as a developer, can ask the device for your location, plus details on what providers are available. There are even ways for you to simulate your location in the emulator, for use in testing your location-enabled applications.
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