Batch Geocoding with Google Geocode API and C#

Introduction: Geocoding is the process of converting addresses into geographic coordinates (like latitude and longitude), which can be used to place on the map. The Google Geocoding API provides a direct way to access a these services via an HTTP request. Please see the full documentation at https://developers.google.com/maps/documentation/geocoding/.

Geocoding API Request :
http://maps.googleapis.com/maps/api/geocode/output?parameters.
Some of the parameters are required and some are optional. The parameters are separated by ampersand (&) character.

Required Parameters:
Address – The address that needs to be geocoded.
Latlng – The latitude/longitude value for which the closest address can be obtained.
Components – Component filter for which geocode needs to be obtained.
Sensor: Whether a geocoding request comes from a device with location sensor.

Geocoding Response:
Geocoding response is returned in the format indicated by the output flag. It is either JSON or XML.

JSON output Formats: API requests a JSON output for Address 600 W. Chicago,IL 70345

http://maps.googleapis.com/maps/api/geocode/json?address=600+w.+Chicago,+IL+70345 &sensor=true_or_false

XML output Format: API requests a JSON output for Address 600 W. Chicago,IL 70345

http://maps.googleapis.com/maps/api/geocode/XML?address=600+w.+Chicago,+IL+70345 &sensor=true_or_false

Both output returns Status and Result elements.

Status Element: returns the status of the request.

Result Element:  it consists of the following:

Types[] Array : types of returned result.
Formatted_address: Address of the location.
Address_component []- contains separated address_components.
Geometry – contains:

(1)    Location: geocoded latitude and Logitude

(2)    Location_type: location Types- the following values are supported:

(A)Rooftop: indicates that the returned result is a precise geocode for which we have location information accurate down to street address precision.

(B)Range_interpolated : indicates that the returned result reflects an approximation (usually on a road) interpolated between two precise points (such as intersections).

©Geometric Center- indicates that the returned result is the geometric center of a result such as a polyline (for example, a street) or polygon (region).

(D)Approximate- indicates that the returned result is approximate
Partial Match- indicates that the geocoder did not return an exact match for the original request, though it was able to match part of the requested address.
Here I’ll provide C# code that calls Google Geocode API. It geocodes addresses in a batch. It takes addresses from a .csv file and returns a .csv file with geocodes (Latitude/Longitude) for each address if it finds a geo location. Also, it returns a status code and location type.
Open a Windows Form Application from Visual studio. Drag a button and call it ‘Geocode’ and paste the following code under private void Geocode_Click(object sender, EventArgs e) events. Prepare a file with Addresses (street address, City, State, and zip) and save it as .csv file. In my code I placed it under c: drive and name it as ‘Address.txt’. Change your file name and path location. Run this program and click the ‘Geocode’ button. It’ll create a ‘AddressWithGeocode.csv’ file under c: drive. You can change the file path and file name.

 Code

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;

using System.Xml;

using System.Xml.Serialization;

using System.IO;

using System.Diagnostics;

using System.Net;

namespace WindowsFormsApplication1

{

    public partial class Form1 : Form

    {

        public Form1()

        {

            InitializeComponent();

        }

        HttpWebRequest request;

        Stream responseReader;

        Uri address;

        public string lng = "";

        string lat = "";

        String location_type = "";

        String partial_match = "";

        String callingServer;

        XmlDocument xmlDoc;

        System.Xml.XmlDocument rootNode = new System.Xml.XmlDocument();

        System.Xml.XmlDocument rootNodeGeo = new System.Xml.XmlDocument();

        private void Form1_Load(object sender, EventArgs e)

        {

        }

        private void Geocode_Click(object sender, EventArgs e)

        {

             StreamReader sr = new StreamReader("C:\\address.txt"); //reading from Address file

            String strline = "";

            String[] _values = null;

            //int x = 0;

            StreamWriter wr = new StreamWriter(@"C:\AddressWithGeoCode.csv"); //writting to AddressWithGeoCode file

           

            wr.WriteLine("Address" + ","+ "City" +","+ "State"+","+"Zip"+ "," + "latitude" + "," + "Longitude" + "," + "Partial Match" + "," + "Location type");

                     

            while (!sr.EndOfStream)

            {

               

                strline = sr.ReadLine();

               

               

                _values = strline.Split(',');

                String Street = _values[0];

                String City = _values[1];

                String State = _values[2];

                String Zip = _values[3];

            

                callingServer = "http://maps.googleapis.com/maps/api/geocode/xml?address=" +

                     Street+City+State+Zip +"&sensor=false";

                address = new Uri(callingServer);

                try

                {

                    //request

                    request = (HttpWebRequest)WebRequest.Create(callingServer);

                }

                catch (Exception ex)

                {

                    MessageBox.Show(ex.ToString());

                }

                request.ContentType = "application/xml; charset=utf-8";

             

                // Get response 

                HttpWebResponse response = (HttpWebResponse)request.GetResponse();

               // Get the response stream into a reader 

                responseReader = response.GetResponseStream();

                XmlTextWriter outXML;

                outXML = new XmlTextWriter("response.xml", null);

                xmlDoc = new XmlDocument();

                xmlDoc.Load(responseReader);

                xmlDoc.Save(outXML);

                outXML.Close();

                responseReader.Close();

                //PopulateNodes(rootNode);

               

                rootNode.Load(@"response.xml");

                XmlNodeList itemList = rootNode.GetElementsByTagName("location");

                XmlNodeList itemList1 = rootNode.GetElementsByTagName("partial_match");

                XmlNodeList itemList2 = rootNode.GetElementsByTagName("location_type");

        

                foreach (XmlNode currNode in itemList)

                {                 

                       lat = currNode.ChildNodes[0].ChildNodes[0].Value.ToString();

                       lng = currNode.ChildNodes[1].ChildNodes[0].Value.ToString();

                       break;

                     

                }       

                foreach (XmlNode currNode in itemList1)

                {           

                     partial_match = currNode.ChildNodes[0].Value.ToString();

                     break;

                }

                foreach (XmlNode currNode in itemList2)

                {

                     location_type = currNode.ChildNodes[0].Value.ToString();

                     break;

                }

             

              

                wr.WriteLine(Street+","+City+","+State+","+Zip + "," + lat + "," + lng + "," + partial_match + "," + location_type);

               }

            MessageBox.Show("Geocoding is done. Pl. check your file");

            wr.Close();

            wr.Close();

          

        }     

    }

}

 output:

Address,City,State,Zip,latitude,Longitude,Partial Match,Location type
1007 Mandalay ct,Naperviile,IL,60563,41.7866794,-88.2149432,,RANGE_INTERPOLATED
5566 West Chester Road,West Chester,OH,45069,39.3302867,-84.439955,,RANGE_INTERPOLATED
3075 Highland Parkway,Downers Grove,IL,60515,41.832551,-88.005306,,ROOFTOP
1275 First Street,West Lafayette,IN,47906,40.4253133,-86.9249989,,ROOFTOP
6 Mortomar Dr,Andover,MA,1810,40.4253133,-86.9249989,,ROOFTOP
601 Old Court Circle,Mekinney,TX,75070,40.4253133,-86.9249989,,ROOFTOP
131 Quill Ridge Dr,Westmont,IL,60559,41.8236432,-87.9571126,,RANGE_INTERPOLATED