Reverse GEO lookup in C#

Nov 19, 2008

Google’s maps API now supports reversed GEO lookup which allows you to find an address based on geo coordinates. All you need is a latitude, a longitude and this handy method:

private const string endPoint = "http://maps.google.com/maps/geo?q={0},{1}&output=xml&sensor=true&key=YOURKEY";

private static string GetAddress(double latitude, double longitude) 

{ 

  string lat = latitude.ToString(CultureInfo.InvariantCulture);

  string lon = longitude.ToString(CultureInfo.InvariantCulture);

  string url = string.Format(endPoint, lat, lon);

  using (WebClient client = new WebClient()) 

  { 

    string xml = client.DownloadString(url);

    XmlDocument doc = new XmlDocument();

    doc.LoadXml(xml);

    XmlNode node = doc.ChildNodes[1].FirstChild.ChildNodes[2].ChildNodes[0];

    return node.InnerText;

  } 

}

It returns the address as a string.

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Comments (2) -

Yoann. B

11/28/2008 2:55:07 PM #

Hi,

Thanks for that article.

I also wrote an article about this subject : blog.sb2.fr/.../...ionGeoTargeting-for-ASPNET.aspx

Andrés Zacchino

12/17/2008 6:32:23 PM #

Great, Gracias

una cosa nomas. error code.

private static string GetAddress(double latitude, double longitude)
{
string lat = latitude.ToString(CultureInfo.InvariantCulture);
string lon = longitude.ToString(CultureInfo.InvariantCulture);
string url = string.Format(endPoint, lat, lon);

using (WebClient client = new WebClient())
{
    string xml = client.DownloadString(url);
    XmlDocument doc = new XmlDocument();
    doc.LoadXml(xml);

    XmlNode nodeStatus = doc.ChildNodes[1].FirstChild.ChildNodes[1].ChildNodes[0];
    if (nodeStatus.InnerText == "200") // if status code is OK
    {
       XmlNode node = doc.ChildNodes[1].FirstChild.ChildNodes[2].ChildNodes[0];
       return node.InnerText; // Primera Direccion que resulve
    }
    else
        return "Not Found";
}
}