Geolocation
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Transcript of Geolocation
![Page 1: Geolocation](https://reader036.fdocuments.us/reader036/viewer/2022081602/54b6e8594a7959aa218b45f6/html5/thumbnails/1.jpg)
HTML 5 geolocation
Kristoffer Snabb
![Page 2: Geolocation](https://reader036.fdocuments.us/reader036/viewer/2022081602/54b6e8594a7959aa218b45f6/html5/thumbnails/2.jpg)
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)
![Page 3: Geolocation](https://reader036.fdocuments.us/reader036/viewer/2022081602/54b6e8594a7959aa218b45f6/html5/thumbnails/3.jpg)
Geolocation API
• Simple interface to get user location with the help of three functions– getCurrentPosition– watchPosition– clearWatch
![Page 4: Geolocation](https://reader036.fdocuments.us/reader036/viewer/2022081602/54b6e8594a7959aa218b45f6/html5/thumbnails/4.jpg)
The interface
• navigator.geolocation.<function name>• successCallback, errorCallback• PositionOptions– enableHighAccuracy – False, True– Timeout– maximumAge– requireCoords – True, False– requestAddress – False, True
![Page 5: Geolocation](https://reader036.fdocuments.us/reader036/viewer/2022081602/54b6e8594a7959aa218b45f6/html5/thumbnails/5.jpg)
The output
• Coords– latitude, longitude, altitude, accuracy,
altitudeAccuracy, heading, speed, verticalSpeed• Address– country, region, county, city, street, streetNumber,
premises, postalCode• timestamp
![Page 6: Geolocation](https://reader036.fdocuments.us/reader036/viewer/2022081602/54b6e8594a7959aa218b45f6/html5/thumbnails/6.jpg)
What makes it complex?
![Page 7: Geolocation](https://reader036.fdocuments.us/reader036/viewer/2022081602/54b6e8594a7959aa218b45f6/html5/thumbnails/7.jpg)
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
![Page 8: Geolocation](https://reader036.fdocuments.us/reader036/viewer/2022081602/54b6e8594a7959aa218b45f6/html5/thumbnails/8.jpg)
Geo IP example
• Mobile phone ip address is ephemeral?• Latency and traceroute information
![Page 9: Geolocation](https://reader036.fdocuments.us/reader036/viewer/2022081602/54b6e8594a7959aa218b45f6/html5/thumbnails/9.jpg)
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
![Page 10: Geolocation](https://reader036.fdocuments.us/reader036/viewer/2022081602/54b6e8594a7959aa218b45f6/html5/thumbnails/10.jpg)
Search query analysis example
![Page 11: Geolocation](https://reader036.fdocuments.us/reader036/viewer/2022081602/54b6e8594a7959aa218b45f6/html5/thumbnails/11.jpg)
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