Building location aware
websites
Paul Hagon

@paulhagon

W3C geolocation specification
... define a secure and privacy-sensitive interface
for using client-side location information in
location-aware Web applications.
http://www.w3.org/2008/geolocation/

IP address inaccurate
Wi-Fi
Triangulation
GPS accurate

Built in GPS

Applications - Objective C

Firefox 3.5 iPhone OS 3.0

Opera Fennec

Google Gears

Privacy
User is alerted
before sending
their location

Privacy
IP address
Access point
Random client identifier
http://www.google.com/privacy-lsf.html
http://www.skyhookwireless.com/howitworks/privacy.php

Starting out
<script type="text/javascript">
function findLocation() {
}
</script>

Make geolocation call
<script type="text/javascript">
function findLocation() {
navigator.geolocation.getCurrentPosition();
}
</script>

Success
<script type="text/javascript">
function findLocation() {
navigator.geolocation.getCurrentPosition(successCallback);
}
function successCallback(position) {
}
</script>

Get the latitude & longitude
<script type="text/javascript">
function findLocation() {
navigator.geolocation.getCurrentPosition(successCallback);
}
function successCallback(position) {
var lat = position.coords.latitude;
var lon = position.coords.longitude;
}
</script>

Do something
<script type="text/javascript">
function findLocation() {
navigator.geolocation.getCurrentPosition(successCallback);
}
function successCallback(position) {
var lat = position.coords.latitude;
var lon = position.coords.longitude;
alert("latitude: " + lat + ", longitude: " + lon);
}
</script>

Error handling
<script type="text/javascript">
function findLocation() {
navigator.geolocation.getCurrentPosition(successCallback,errorCallback);
}
function successCallback(position) {
var lat = position.coords.latitude;
var lon = position.coords.longitude;
alert("latitude: " + lat + ", longitude: " + lon);
}
function errorCallback() {
// Do something with the error
}
</script>

Error handling
<script type="text/javascript">
function findLocation() {
if(navigator.geolocation) {
navigator.geolocation.getCurrentPosition(successCallback,errorCallback);
} else {
// Do something to alert the user
}
}
function successCallback(position) {
var lat = position.coords.latitude;
var lon = position.coords.longitude;
alert("latitude: " + lat + ", longitude: " + lon);
}
function errorCallback() {
// Do something with the error
}
</script>

Finished script
<script type="text/javascript">
function findLocation() {
if(navigator.geolocation) {
navigator.geolocation.getCurrentPosition(successCallback,errorCallback);
} else {
// Do something to alert the user
}
}
function successCallback(position) {
var lat = position.coords.latitude;
var lon = position.coords.longitude;
alert("latitude: " + lat + ", longitude: " + lon);
}
function errorCallback() {
// Do something with the error
}
</script>

Reverse geocoding
Take a latitude and longitude
and return an address
-35.300114,149.132726
Parkes ACT 2620, Australia

Parkes
Parkes, ACT
Parkes, NSW
Henry Parkes

Yahoo Placemaker
Extracts location information
from text or a URL
http://developer.yahoo.com/geo/placemaker/

Parkes Australia
Name Type WOE ID Latitude Longitude
Parkes, New Town 1104910 -33.1369 148.175
South Wales, AU
Parkes, Canberra, Suburb 7225344 -35.3028 149.129
Australian Capital
Territory, AU

Open Australia
Repurposing Australian Hansard so people
can keep track of their representatives
http://www.openaustralia.org/

http://www.openaustralia.org/debates/?id=2009-06-23.8.1
Match Real name Type WOE ID Latitude Longitude
Melbourne Melbourne, Town 1103816 -37.8175 144.967
Victoria, AU
Warringah Warringah, County 55864177 -33.7033 151.25
New South
Wales, AU
North Sydney North Sydney, Suburb 1107124 -33.8399 151.208
Sydney, New
South Wales,
AU

Can I use this yet?
YES

within 1 week 50% upgraded
to iPhone OS 3.0
(iPhone 0.1% of traffic to NLA)

For NLA - Firefox 3.5 is around
1% of users (2nd most popular
version of Firefox)

More than 95% of the NLA
users have the potential to use
these features if they install
Google Gears

Thanks!
slideshare.net/paulhagon
delicious.com/paulhagon/wsg09
www.paulhagon.com
@paulhagon
phagon@nla.gov.au