Google Gears GeolocationAPI
详见：http://code.google.com/p/gears/wiki/GeolocationAPI
使用方法：curl -d ‘{”version”: “1.1.0″,”host”: “maps.google.com”,”home_mobile_country_code”:310,”home_mobile_network_code”: 410,”radio_type”: “gsm”,”carrier”: “Vodafone”,”request_address”: true,”address_language”: “en_GB”,”location”: {”latitude”: 51.0,”longitude”: -0.1},”cell_towers”: [{ "cell_id": "42", "location_area_code": 415,"mobile_country_code": 310,"mobile_network_code": 410,"age": 0,"signal_strength": -60,"timing_advance": 5555},{"cell_id": "88","location_area_code": 415,"mobile_country_code": 310,"mobile_network_code": 580,"age": 0,"signal_strength": -70,"timing_advance": 7777}],”wifi_towers”: [{"mac_address": "01-23-45-67-89-ab","signal_strength": 8,"age": 0},{"mac_address": "01-23-45-67-89-ac","signal_strength": 4,"age": 0}]}’ http://www.google.com/loc/json
非必须的可以省略不提交。