How do I automatically find a user's location?

Question

I am currently working on a show listing website. I am going to display show information by location for the user sorted in a variety of different ways.

I know I could ask the user where they are located when they first sign into the site, but I've seem to notice that many sites have this capability built-in to detect location automatically? (Ex. see Last.fm "Events: Concert Listings in your area").

Anyone have any idea how they do this? I'm currently building my website in Rails.

Answer 1

you google maps api to geo-locate user. they have a function for that.

Answer 2

They usually do using IP resolution by IP tables. ip2nation might give some idea

Answer 3

Here's a link to the documentation on the relevant Google Maps API:

http://code.google.com/apis/ajax/documentation/#ClientLocation

It shows an example of how to use it:

/**
 * Set the currentState_ and currentCountry_ properties based on the client's
 * current location (when available and in the US), or to the defaults.
 */
InTheNews.prototype.setDefaultLocation_ = function() {
  this.currentState_ = this.options_.startingState;
  if (google.loader.ClientLocation &&
      google.loader.ClientLocation.address.country_code == "US" &&
      google.loader.ClientLocation.address.region) {

    // geo locate was successful and user is in the United States. range
    // check the region so that we can safely use it when selecting a
    // state level polygon overlay
    var state = google.loader.ClientLocation.address.region.toUpperCase();
    if (InTheNews.stateNames[state]) {
      this.currentState_ = state;
    }
  }
  this.currentCountry_ = "US";
}

And tells you what you will get from it:

When populated, the google.loader.ClientLocation object is populated with the following metro-level granularity properties:

• ClientLocation.latitude — supplies the low resolution latitude associated with the client's IP address

• ClientLocation.longitude — supplies the low resolution longitude associated with the client's IP address

• ClientLocation.address.city — supplies the name of the city associated with the client's IP address

• ClientLocation.address.country — supplies the name of the country associated with the client's IP address

• ClientLocation.address.country_code — supplies the name of the ISO 3166-1 country code associated with the client's IP address

• ClientLocation.address.region — supplies the country specific region name associated with the client's IP address

Answer 4

You might like to look at MaxMind's GeoLite soluton for IP location. An open source solution.

Answer 5

There is a new way , infact its the better way to find geo-location, because Browser will natively support W3C api for geolocation... You should checkout GeoMereLaal