Location Guard for Chrome
More About Location Guard
This extension allows you to enjoy the useful applications of geolocation while protecting your privacy. It does so by reporting a fake location to websites, obtained by adding a certain amount of "noise" to the real location. The noise is randomly selected in a way that ensures that the real location cannot be inferred with high accuracy.
Three configurable privacy levels are provided. The higher the privacy level the greater the amount of noise, which gives better privacy at the expense of a less accurate fake location. This can be configured per-website for flexibility: a more accurate location can be provided for driving directions than for a weather forecast. There's also an option to use a fixed location, instead of adding noise to the real one. This offers the best privacy (no dependence on the real location at all), at the cost of very low accuracy.