Working with the Google Location API

Question

Forgive me for my ignorance, but after several hours of searching, I'm having little luck.

Anyway, I am attempting to write a small desktop application that will allow a user to enter an address and then have their approximate location returned in GPS coordinates. From what I can tell, Google provides a geocoding API[1] that allows requests in the following form:

http://maps.googleapis.com/maps/api/geocode/output?parameters

While I'm familiar with writing basic C Sharp applications, I really have no idea where to start when it comes to interfacing with this API. Any help that you guys could provide would be greatly appreciated.

Solution 1

Fully documented .NET library -

Google Maps Web Services API wrapper for .NET https://github.com/maximn/google-maps/

//Directions
DirectionsRequest directionsRequest = new DirectionsRequest()
{
        Origin = "NYC, 5th and 39",
        Destination = "Philladephia, Chesnut and Wallnut",
};

        DirectionsResponse directions = MapsAPI.GetDirections(directionsRequest);

//Geocode
GeocodingRequest geocodeRequest = new GeocodingRequest()
{
        Address = "new york city",
};


GeocodingResponse geocode = MapsAPI.GetGeocode(geocodeRequest);

Console.WriteLine(geocode);

//Elevation
ElevationRequest elevationRequest = new ElevationRequest()
{
        Locations = new Location[] { new Location(54, 78) },
};


ElevationResponse elevation = MapsAPI.GetElevation(elevationRequest);

Console.WriteLine(elevation);

Solution 2

Here is a sample code to get what you want

using System;
using System.Web;
using System.Net;
using System.Runtime.Serialization.Json;

namespace GoogleMapsSample
{
    public class GoogleMaps
    {

        /// <summary>
        /// 
        /// </summary>
        /// <param name="address"></param>
        /// <returns></returns>
        public static GeoResponse GetGeoCodedResults(string address)
        {
            string url = string.Format(
                    "http://maps.google.com/maps/api/geocode/json?address={0}&region=dk&sensor=false",
                    HttpUtility.UrlEncode(address)
                    );
            var request = (HttpWebRequest)HttpWebRequest.Create(url);
            request.Headers.Add(HttpRequestHeader.AcceptEncoding, "gzip,deflate");
            request.AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate;
            DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(GeoResponse));
            var res = (GeoResponse)serializer.ReadObject(request.GetResponse().GetResponseStream());
            return res;
        }


    }

and you helper class would be

 namespace GoogleMapsSample
{
    [DataContract]
    public class GeoResponse
    {
        [DataMember(Name = "status")]
        public string Status { get; set; }
        [DataMember(Name = "results")]
        public CResult[] Results { get; set; }

        [DataContract]
        public class CResult
        {
            [DataMember(Name = "geometry")]
            public CGeometry Geometry { get; set; }

            [DataContract]
            public class CGeometry
            {
                [DataMember(Name = "location")]
                public CLocation Location { get; set; }

                [DataContract]
                public class CLocation
                {
                    [DataMember(Name = "lat")]
                    public double Lat { get; set; }
                    [DataMember(Name = "lng")]
                    public double Lng { get; set; }
                }
            }
        }

        public GeoResponse()
        { }
    }


}

Then you can use this code in your control/winforms like this

            GeoResponse response = new GeoResponse();
            response = GoogleMaps.GetGeoCodedResults(TextBoxPostcode.Text);

and build the JS on the code behind using StringBuilder or anyting else

Solution 3

The Geocode API is rather simple, to get lat/lon from the api you only need to 3 params: output, sensor and address.

output the output format you want, json or xml (IIRC)

sensor should be a boolean indicating weather or not the value comes from a sensor such as a GPS chip.

address should be the address (don't forget to url encode it) you wish to geocode.

This is an example, where I geocode my office address, and get JSON in response: http://maps.googleapis.com/maps/api/geocode/json?sensor=false&address=1+Maritime+Plaza+San+Francisco+CA

If you navigate to that you should see something like:

{
  "status": "OK",
  "results": [ {
    "types": [ "street_address" ],
    "formatted_address": "1 Maritime Plaza, San Francisco, CA 94111, USA",
    "address_components": [ {
      "long_name": "1",
      "short_name": "1",
      "types": [ "street_number" ]
    }, {
      "long_name": "Maritime Plaza",
      "short_name": "Maritime Plaza",
      "types": [ "route" ]
    }, {
      "long_name": "San Francisco",
      "short_name": "San Francisco",
      "types": [ "locality", "political" ]
    }, {
      "long_name": "San Francisco",
      "short_name": "San Francisco",
      "types": [ "administrative_area_level_3", "political" ]
    }, {
      "long_name": "San Francisco",
      "short_name": "San Francisco",
      "types": [ "administrative_area_level_2", "political" ]
    }, {
      "long_name": "California",
      "short_name": "CA",
      "types": [ "administrative_area_level_1", "political" ]
    }, {
      "long_name": "United States",
      "short_name": "US",
      "types": [ "country", "political" ]
    }, {
      "long_name": "94111",
      "short_name": "94111",
      "types": [ "postal_code" ]
    } ],
    "geometry": {
      "location": {
        "lat": 37.7953907,
        "lng": -122.3991803
      },
      "location_type": "ROOFTOP",
      "viewport": {
        "southwest": {
          "lat": 37.7922431,
          "lng": -122.4023279
        },
        "northeast": {
          "lat": 37.7985383,
          "lng": -122.3960327
        }
      }
    }
  } ]
}

If you take the lat/lon provided and place it on a map you see a pointer on my office building.

Solution 4

I recently had to build a Store Locator for a project I am working on. I have never before this used any of the Google or Bing API's. Using this tutorial I was able to get a pretty good grasp of the Location API. I would suggest going through this tutorial and by the end of the three tutorials you should have a good understanding.

Building a Store Locator ASP.NET Application Using Google Maps API (Part 1)

Building a Store Locator ASP.NET Application Using Google Maps API (Part 2)

Building a Store Locator ASP.NET Application Using Google Maps API (Part 3)

Solution 5

By using GuigleAPI nuget you can simply do:

GoogleGeocodingAPI.GoogleAPIKey = "YOUR API KEY";
var result = await GoogleGeocodingAPI.GetCoordinatesFromAddressAsync("100 Market St, Southbank");
var latitude = result.Item1;
var longitude = result.Item2;

Just install it with the nuget command Install-Package Easyforce.GuigleAPI and you're good to go.

Check this answer for more details: https://stackoverflow.com/a/44484010/1550202

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Comments

[Admin]

I'll be sure to try this out. I just wanted to say thanks in the meantime, I really appreciate it.

[Cees Timmerman]

If you add the optional region parameter, it will try harder to return a location there.

[czetsuya]

Anybody tried this API on MVC3 c# app? In my side it's loading page for a long time :-? But when I run a console app everything is working fine.

[Killnine]

@czetsuya I had the same problem with the latest version on GitHub last night. just appears to hang and never recover...

[Maxim]

We just fixed it few days ago. Please make sure you're running on the latest version. In addition, I'll upload a nuget package in the next days.

[Johann]

@Maxim - The library is awesomely easy to use, thanks :) I'm still having this issue though, has the NuGet package been updated with a version that fixes this problem? I'm not running with an Enterprise license yet, but we are planning on purchasing one when we get everything working.

[Brendon Bezuidenhout]

Thanks for this @Maxim - One thing I'm curious about is how to change the unit system from metric to imperial for instance?

[Maxim]

This is just wrapping Google's Maps API, it doesn't add any functionality. As I remember they don't support it but you can do it very easily in your code.