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C#: Geocoding to get Latitude and Longitude using Google Maps API

Geocoding is the process of getting the latitude and longitude of an address or set of addresses, which you can use to place markers or position the map.

Geocoding can be done on the client-side as well as on the server-side, based on your requirements you need to choose one out of both options.

For geocoding I am using Google Maps API which is quite reliable and faster in response to other geocoding APIs.

You can check the JSON response by directly running the API with the address on the browser window or you can take service of POSTMAN as well. Sample JSON response of Google Map API is given below:

Requested geocoding of "Gurgaon" using Google Maps API
Request: http://maps.googleapis.com/maps/api/geocode/json?sensor=true&address=Gurgaon
Response:
{
    "results" : [
       {
           "address_components" : [
              {
                  "long_name" : "Gurgaon",
                  "short_name" : "Gurgaon",
                  "types" : [ "locality", "political" ]
              },
              {
                  "long_name" : "Gurgaon",
                  "short_name" : "Gurgaon",
                  "types" : [ "administrative_area_level_2", "political" ]
              },
              {
                  "long_name" : "Haryana",
                  "short_name" : "HR",
                  "types" : [ "administrative_area_level_1", "political" ]
              },
              {
                  "long_name" : "India",
                  "short_name" : "IN",
                  "types" : [ "country", "political" ]
              },
              {
                  "long_name" : "122001",
                  "short_name" : "122001",
                  "types" : [ "postal_code" ]
              }
           ],
           "formatted_address" : "Gurgaon, Haryana 122001, India",
           "geometry" : {
               "bounds" : {
                   "northeast" : {
                       "lat" : 28.5458782,
                       "lng" : 77.12264519999999
                   },
                   "southwest" : {
                       "lat" : 28.303795,
                       "lng" : 76.8569182
                   }
               },
               "location" : {
                   "lat" : 28.4594965,
                   "lng" : 77.0266383
               },
               "location_type" : "APPROXIMATE",
               "viewport" : {
                   "northeast" : {
                       "lat" : 28.5458782,
                       "lng" : 77.12264519999999
                   },
                   "southwest" : {
                       "lat" : 28.303795,
                       "lng" : 76.8569182
                   }
               }
           },
           "place_id" : "ChIJWYjjgtUZDTkRHkvG5ehfzwI",
           "types" : [ "locality", "political" ]
       }
    ],
    "status" : "OK"
}

Below C# code demonstrates calling the Google Maps geocoding service. To parse returned JSON data Newtonsoft.Json library is used and mapping classes are used to Deserialize JSON responses returned by Google Map API.

using Newtonsoft.Json;
using System.Configuration;
using System.IO;
using System.Linq;
using System.Net;
using System.Web;

namespace GoogleGeoApp
{
    public class GoogleGeoCoder
    {
        public static GeoLocation GeoLocate(string address)
        {
            var requestUrl = "http://maps.googleapis.com/maps/api/geocode/json?address="
                             + HttpUtility.UrlEncode(address);

            var httpWebRequest = (HttpWebRequest)WebRequest.Create(requestUrl);
            httpWebRequest.ContentType = "application/json;";
            httpWebRequest.Method = "GET";

            GeoLocation gLocation = null;
            try
            {
                var httpResponse = (HttpWebResponse)httpWebRequest.GetResponse();
                using (var reader = new StreamReader(httpResponse.GetResponseStream()))
                {
                    var response = reader.ReadToEnd();

                    var gResponse = JsonConvert.DeserializeObject<GeoResponse>(response);
                    if (gResponse.Status.ToUpper() == "OK")
                    {
                        var geoResult = gResponse.Results.FirstOrDefault();

                        if (geoResult != null)
                        {
                            gLocation = geoResult.Geometry.Location;
                        }
                    }
                }
            }
            catch
            {
            }
            return gLocation;
        }
    }
    public class GeoLocation
    {
        public double Lat { get; set; }

        public double Lng { get; set; }
    }
    public class GeoGeometry
    {
        public GeoLocation Location { get; set; }
    }
    public class GeoResult
    {
        public GeoGeometry Geometry { get; set; }
    }
    public class GeoResponse
    {
        public string Status { get; set; }

        public GeoResult[] Results { get; set; }
    }
}

You can call GeoLocate method as:
var gLoc = GoogleGeoCoder.GeoLocate("Gurgaon");

And it’ll provide you latitude and longitude of the given address

Note: If you have a Google Maps API key you can use that key while requesting for geocoding, but use HTTPS instead of HTTP, as HTTP won’t work in case of Map API request with key. Sample request with key is like:
https://maps.googleapis.com/maps/api/geocode/json?key=API-KEY&address=Gurgaon

If you use an API key with the HTTP request, you'll get an error message in JSON response as given below:
{
   "error_message" : "Requests to this API must be over SSL. Load the API with \"https://\" instead of \"http://\".",
   "results" : [],
   "status" : "REQUEST_DENIED"
}
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