Quick code snippets to easily set up a background task to poll geolocation information on iOS on a 10 second interval

alloy.js

// Setup Geoloaction Background Tasks for the app
Ti.Geolocation.purpose = "This app would like to use your location.";
Ti.App.iOS.registerBackgroundService({url: "geoBackgroundTask.js"});


/**
 * Note: If you are programming in a standard project for Titanium, 
 * this snippet would probably go in your app.js file
 * /

geoBackgroundTask.js

/**
 * Setting up Geolocation to run as a background Task in IOS
 *
 * Include the underscore library - you need to do this since background tasks run outside of the scope
 * of the main application. Its found under the alloy folder for alloy based projects, otherwise you can
 * find it here:
 * 
 * http://underscorejs.org/
 */
Ti.include("alloy/underscore.js");

function getCurrentPosition() {

  // Setup a variable to store the locally stored list.
	var waypoints = Ti.App.Properties.getList("waypoints");
	
	//Call the Geolocation API to get current position (passes a callback function)
	Ti.Geolocation.getCurrentPosition(function(e){
		
		// Create a marker object for the lat/long and timestamp
		var waypoint = {
			timestamp: new Date(),
			latitude: e.coords.latitude,
			longitude: e.coords.longitude,
		};
		
		//Just in case this is the list hasn't been initialized with data, make sure we create an array
		if(!_.isArray(waypoints)){
			waypoints = [];	
		}
		
		// Add the way point to the list
		waypoints.push(waypoint);
		
		// Update the persistent List
		Ti.App.Properties.setList("waypoints", waypoints );
		Ti.API.info("GEOMARKERS: "+ JSON.stringify(waypoints));
		
		//Cleanup
		waypoints = null;
	});
}

/**
 * Setup Interval check for background service. Current Position should be recorded, and added to an
 * locally stored list.
 */
setInterval(getCurrentPosition, 10000);

tiapp_snippet.xml

<!--
  Add this snippet within the <ti:app> tags of your tiapp.xml file
-->
<backgroundModes>
  	<mode>location</mode>
</backgroundModes>