How does Chrome know my geolocation?

Question

Chrome seems to be very accurate in detecting my location. How does it do it? Can you point me to the source code?

Answer 1

Geolocation can be calculated based on:

1. GPS (if available)
2. Available wi-fi networks and signal strengths
3. Available cell towers and signal strengths
4. IP Address lookup

See the W3C Geolocaton API and Google Gears API (which Chrome's/W3C Geolocation API is based on).

Chromium's geolocation source code can be viewed online.