A presentation I had

1. HTML 5 geolocation
Kristoffer Snabb

2. Scope of the working group
• Retrieve a users location only once
• Retrieve several data points over time
• Retrieve a sequence of locations at irregular
intervals (e.g. each time a photo is taken)

3. Geolocation API
• Simple interface to get user location with the
help of three functions
– getCurrentPosition
– watchPosition
– clearWatch

4. The interface
• navigator.geolocation.<function name>
• successCallback, errorCallback
• PositionOptions
– enableHighAccuracy – False, True
– Timeout
– maximumAge
– requireCoords – True, False
– requestAddress – False, True

5. The output
• Coords
– latitude, longitude, altitude, accuracy, altitudeAcc
uracy, heading, speed, verticalSpeed
• Address
– country, region, county, city, street, streetNumber,
premises, postalCode
• timestamp

6. What makes it complex?

7. Triangulation/forward link examples
• GPS
– Accuracy about 10m
– Does not work indoors
• Wi-Fi
– Accuracy about 20m
– Works indoors
• Cell tower
– Accuracy depends on cell coverage

8. Geo IP example
• Mobile phone ip address is ephemeral?
• Latency and traceroute information

9. Social network example
• likelihood of friendship with a person is
decreasing with distance
• Your friend shared location with GPS
• Your friends profile has an address
 Good enough for marketing, good
computational performance and increased
location probability when used with geo IP

10. Search query analysis example
WWW 2008 / Refereed Track: Search - Query Analysis April 21-25, 2008 · Beijing, China
F i gur e 8: Spher es of i nfl uence of basebal l t eam s.

11. References
• Spatial variation in search engine
queries, www2008, L. Backstrom, J. Kleinberg, R.
Kumar, J. Novak
• Find me if you can: improving geographical
prediction with social and spatial
proximity, www2010, L. Backstrom, E. Sun, C.
Marlow,
• Uses of W3C’s geolocation API, CINTI 2010, B.
Pejic, A. Pejic, Z. Covic
• The locative Web, locweb2008, E. Wilde, M.
Kofahl