Webservice to get distance from Latitude and Longitude

 Sample Application for Web Service


Write this code on WebService Page

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Services;

[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
// To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line.
// [System.Web.Script.Services.ScriptService]

public class Service : System.Web.Services.WebService
{
    public Service () {

    }
    [WebMethod]
    public double distanceFrom(double lat1, double lng1, double lat2, double lng2)
    {
        double dist;       
        dist= distance(lat1, lng1, lat2, lng2);
        return dist;
    }
    private double distance(double lat1, double lon1, double lat2, double lon2)
    {
        double theta = lon1 - lon2;
        double dist = Math.Sin(deg2rad(lat1)) * Math.Sin(deg2rad(lat2)) + Math.Cos(deg2rad(lat1)) * Math.Cos(deg2rad(lat2)) * Math.Cos(deg2rad(theta));
        dist = Math.Acos(dist);
        dist = rad2deg(dist);
        dist = dist * 60 * 1.1515;
        //For Kilometer
       // dist = dist * 1.609344;
       //For S Miles
       //   dist = dist * 0.8684;
        dist = Math.Round(dist, 2);
        return (dist);
    }
    private double deg2rad(double deg)
    {
        return (deg * Math.PI / 180.0);
    }
    private double rad2deg(double rad)
    {
        return (rad / Math.PI * 180.0);
    }
}

After This Add Web Reference in your site and write code on your aspx.cs page.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using ServiceReference1;

public partial class Test : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }
    protected void Button1_Click(object sender, EventArgs e)
    {
       
        ServiceReference1.ServiceSoapClient sp=new ServiceSoapClient();
        double lat1=Convert.ToDouble(TextBox1.Text);
        double lat2 = Convert.ToDouble(TextBox3.Text); ;
        double lon1=Convert.ToDouble(TextBox2.Text);
        double lon2 = Convert.ToDouble(TextBox4.Text); ;
        double str = sp.distanceFrom(lat1,lon1,lat2,lon2);
        TextBox5.Text = str.ToString()+' '+"Miles";
    }
}