Execution time more Required in foreach loop

Question

I have used 3 or 4 for each loop my code, as well as one internet URL, hit in one loop.

I have used Asynchronous in my code but it same time required for execution. 

 

how to optimize execution time in below code suggest me....

 

public string GetCorrectDistance(double lat1,double long1,double lat2,double long2)
      {
          string s;
          string d = null;


              using (WebClient client = new WebClient())
              {
                  s = client.DownloadString("http://yournavigation.org/api/dev/route.php?flat=" + lat1 + "&flon=" + long1 + "&tlat=" + lat2 + "&tlon=" + long2 + "&v=motorcar&fast=1&instructions=1");
              }
              XmlDocument _doc = new XmlDocument();
              _doc.LoadXml(s);
              XmlNodeList _fnames = _doc.GetElementsByTagName("distance");
              for (int _i = 0; _i < _fnames.Count; ++_i)
              {
                  d = _fnames[_i].InnerText;
              }

            return d;
      }
      public async Task<ActionResult>  DateWLocationKM(int UserId =0)
      {



              var _checlAuth = this.CheckAuthentication();
          if (_checlAuth != null)
          {
              return _checlAuth;
          }
          ViewModel.MobileGPSLocation.GPSDateW gps = new ViewModel.MobileGPSLocation.GPSDateW();

          List<ViewModel.MobileGPSLocation.GPSDateW> listsample = new List<ViewModel.MobileGPSLocation.GPSDateW>();
          List<ViewModel.MobileGPSLocation.MobileGPSLocation> listgps = new List<ViewModel.MobileGPSLocation.MobileGPSLocation>();

          string lastmonth = Repository.IndainTime.getCreatedDate().Date.AddMonths(-1).ToString();
          // var ccheckdata = WebApp.MvcApplication.listGPSLocation.Where(a => a.UserId == UserId && Convert.ToDateTime(a.CreatedDate).Date>=Convert.ToDateTime(lastmonth).Date ).OrderByDescending(a => a.Id).ToList().Select(a=>a.CreatedDate.Date).Distinct();
          string df =DateTime.Now.Date.ToString("yyyy-MM-dd");
          string dg = Convert.ToDateTime(lastmonth).Date.ToString("yyyy-MM-dd");
          var ccheckdata = GETAllLocation(UserId).Where(a => a.UserId == UserId && Convert.ToDateTime(a.CreatedDate).Date >= Convert.ToDateTime(dg).Date && Convert.ToDateTime(a.CreatedDate).Date <= Convert.ToDateTime(df).Date).OrderByDescending(a => a.Id).ToList().Select(a=>Convert.ToDateTime(a.CreatedDate).Date).Distinct();
          //var ccheckdata = WebApp.MvcApplication.listGPSLocation.Where(a => a.UserId == UserId && Convert.ToDateTime(a.CreatedDate) >=Convert.ToDateTime(dg).Date  && Convert.ToDateTime(a.CreatedDate) <= Convert.ToDateTime(df).Date).ToList();
            foreach (var item in ccheckdata)
          {
              ViewModel.MobileGPSLocation.GPSDateW model = new ViewModel.MobileGPSLocation.GPSDateW();
              double d =await ListGPS(item.Date.ToString(), item.Date.ToString(), UserId);
              model.dateTime = item.Date.ToString();
              model.countkM = d;
              model.Id = UserId;
              listsample.Add(model);
          }
          gps.list = listsample;
          gps.Id = UserId;
          return View(gps);
      }
       public async Task<double> ListGPS(string date, string endDate, int Id)
      {

          sum = 0;
          List<ViewModel.MobileGPSLocation.MobileGPSLocation> listgps = new List<ViewModel.MobileGPSLocation.MobileGPSLocation>();
          string area = null;
         var ccheckdata = listGPSLocation.Where(a => a.UserId == Id && Convert.ToDateTime(a.CreatedDate).Date >= Convert.ToDateTime(date).Date && Convert.ToDateTime(a.CreatedDate).Date <= Convert.ToDateTime(endDate).Date).OrderByDescending(a => a.Id).ToList();
          #region
          double lat1 = 0;
          double lat2 = 0;
          double long1 = 0;
          double long2 = 0;
          foreach (var s in ccheckdata)
          {
              ViewModel.MobileGPSLocation.MobileGPSLocation ss = new ViewModel.MobileGPSLocation.MobileGPSLocation();
              if (area == null)
              {
                  area = s.Address;
                  area = s.Address;
                  ss.Lat = s.Lat;
                  ss.Long = s.Long;
                  ss.Id = s.Id;
                  ss.Address = s.Address;
                  listgps.Add(ss);

              }
              else if (area == s.Address)
              {
                  //ss.Lat = s.Lat.Trim();
                  //ss.Long = s.Long.Trim();
                  //ss.Id = s.Id;
                  //ss.Address = s.Address.Trim();
                  //listgps.Add(ss);
                  area = s.Address;
              }
              else
              {
                  ss.Lat = s.Lat.Trim();
                  ss.Long = s.Long.Trim();
                  ss.Id = s.Id;
                  ss.Address = s.Address.Trim();
                  listgps.Add(ss);
                  area = s.Address;

              }

          }

          #endregion
          #region
          foreach (var item in listgps.OrderBy(a => a.Id))
          {
              if (lat1.Equals(0))
              {

                  lat1 = Convert.ToDouble(item.Lat);
                  long1 = Convert.ToDouble(item.Long);
              }
              else if (lat2.Equals(0))
              {
                  lat2 = Convert.ToDouble(item.Lat);
                  long2 = Convert.ToDouble(item.Long);
              }
              else if (lat1 != 0 && lat2 != 0)
              {
                  //double che = distance(lat1, long1, lat2, long2, 'K');
                  //string newFormat = ;

                  sum += Convert.ToDouble((GetCorrectDistance(lat1, long1, lat2, long2)).ToString());

                  lat1 = lat2;
                  long1 = long2;
                  //  double convertdist = Convert.ToDouble(d.Value);
                  lat2 = Convert.ToDouble(item.Lat);
                  long2 = Convert.ToDouble(item.Long);
              }

          }

          if (listgps.Count() > 0)
          {
              if (lat1 != 0 && lat2 != 0)
              {
                  // double che = distance(lat1, long1, lat2, long2, 'K');
                  //string newFormat = ;
//below function one url hit each time then we will get output  ...this url intenet is required.
                  sum += Convert.ToDouble((GetCorrectDistance(lat1, long1, lat2, long2)).ToString());

              }
          }
          #endregion



          return sum;
      }