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# Calculating the distance between two locations in Symbian Web Runtime

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Article Metadata
Tested with
Devices(s): Nokia 5800 XpressMusic
Compatibility
Platform(s): S60 5th Edition
Article
Keywords: device.getServiceObject(), Service.Location, Service.Location.GetLocation(), Service.Location.Calculate()
Created: (17 Nov 2008)
Last edited: hamishwillee (13 Apr 2011)

## Overview

This code snippet demonstrates how to calculate the distance between two locations using the Location Service API of Web Runtime (WRT).

## Source: widget.xhtml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
<link rel="StyleSheet" href="style/general.css" type="text/css" />
<script type="text/javascript" src="script/script.js" />
<title>WRT Application</title>
</head>
<body>
<div id="bodyContent" class="bodyContent">
<input type="button" value="Display distance"
onclick="displayDistance();" />
</div>
</body>
</html>

## Source: script.js

var serviceObj = null;
var distanceCriteria = null;

window.onload = init;

// Initializes the widget
function init() {
// Obtain the Location service object
try {
serviceObj = device.getServiceObject("Service.Location", "ILocation");
} catch (ex) {
alert("Service object cannot be found.");
return;
}

// Initialize the criteria for the service object
criteria = new Object();
criteria.LocationInformationClass = "BasicLocationInformation";

distanceCriteria = new Object();
distanceCriteria.MathRequest = "FindDistance";
}

function displayDistance() {
if (serviceObj == null) {
alert("Service object has not been initialized.");
return;
}

// Obtain the location information (asynchronous)
try {
var result = serviceObj.ILocation.GetLocation(criteria,
locationDataReady);
} catch (ex) {
alert(ex);
return;
}
}

// Called when the location data has been obtained
function locationDataReady(transId, eventCode, result) {
// On error situation, display the error message
if (eventCode == 4) {
alert("Error " + result.ErrorCode + ": " + result.ErrorMessage);
return;
}

// The source location is where the device now is
var srcLocation = new Object();
srcLocation.Latitude = result.ReturnValue.Latitude;
srcLocation.Longitude = result.ReturnValue.Longitude;
srcLocation.Altitude = result.ReturnValue.Altitude;

// The destination location is initialized to specific coordinates
var destLocation = new Object();
destLocation.Latitude = 61.0;
destLocation.Longitude = 24.0;
destLocation.Altitude = 0;

// Calculate the distance between the source and the destination
var distance = calculateDistance(srcLocation, destLocation);
// Display the distance rounded to two decimals
alert(distance.toFixed(2) + " m");
}

// Calculates the distance from the source location to the destination location
function calculateDistance(srcLocation, destLocation) {
var distance = 0.0;
distanceCriteria.DistanceParamSource = srcLocation;
distanceCriteria.DistanceParamDestination = destLocation;
try {
var distResult = serviceObj.ILocation.Calculate(distanceCriteria);
distance = distResult.ReturnValue;
} catch (ex) {
alert(ex);
distance = undefined;
}
return distance;
}

## Postconditions

The distance between two locations is displayed.

## See also

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