Truly revolutionary: now you can write geolocation applications directly in the browser, rather than develop native apps for particular devices. This concise book demonstrates the W3C Geolocation API in action, with code and examples to help you build HTML5 apps using the "write once, deploy everywhere" model. Along the way, you get a crash course in geolocation, browser support, and ways to integrate the API with common geo tools like Google Maps. Ideal for experienced JavaScript developers. Learn how geo information is gathered from different sources, depending on the device Discover how coordinate systems work, including geodetic systems and datums Use the API to collect location information from a user’s browser with JavaScript code Place geo information on a map using the Google Maps or ArcGIS JavaScript APIs Save geo data with databases, the Keyhole Markup Language, or the shapefile format Be familiar with several practical uses for geo data, such as geomarketing, geosocial, geotagging, and geo-applications