How to parse Google Maps direction api's “overview_polyline”

How to parse Google Maps direction api's “overview_polyline”

1.In Javascript I use this function to decode Polyline‌​s in my Node.JS program. – josebetomex
// These functions decode a polyline pointstring.
// The first is mine and simply links the second function to the form.
function decode () {
  var instring;
  var outstring;
  var points;
 
  instring = document.getElementById("polylineDecoder").encodedPolylineIn.value;
  instring = instring.replace(/\\\\/g, "\\");
  points = decodeLine(instring);
  outstring = "";
  for(i=0; i < points.length; i++) {
    outstring = outstring + points[i][0] + ", " + points[i][1] + "\n";
  }
  document.getElementById("polylineDecoder").decodedPolylineOut.value = outstring;
}
// This function is from Google's polyline utility.
function decodeLine (encoded) {
  var len = encoded.length;
  var index = 0;
  var array = [];
  var lat = 0;
  var lng = 0;
  while (index < len) {
    var b;
    var shift = 0;
    var result = 0;
    do {
      b = encoded.charCodeAt(index++) - 63;
      result |= (b & 0x1f) << shift;
      shift += 5;
    } while (b >= 0x20);
    var dlat = ((result & 1) ? ~(result >> 1) : (result >> 1));
    lat += dlat;
    shift = 0;
    result = 0;
    do {
      b = encoded.charCodeAt(index++) - 63;
      result |= (b & 0x1f) << shift;
      shift += 5;
    } while (b >= 0x20);
    var dlng = ((result & 1) ? ~(result >> 1) : (result >> 1));
    lng += dlng;
    array.push([lat * 1e-5, lng * 1e-5]);
  }
  return array;
}
//a}oeFfljjViEh@pAnS|AxU?v@UfBAPKVOd@GR?b@{@TEFCLIj@WrCSxCUhDAnA?VENOd@Kt@EvAClCDlAEp@Oj@S^ELAROlAGXI\Ob@e@hCeAxGU`DCdA@~@HzED`EBt@Jn@VbAz@`B|@tA~@vAt@rA\v@X~@Pt@Df@Ab@Et@In@qArFOh@gAbEId@Cz@F`CFx@b@rD\dBd@tAn@xBNf@FTl@vBj@dCl@tDHz@Vn@Tj@Ll@Xt@B|@Hz@PZJNR\H^Dh@@d@BXHVH^Dj@?rBJp@@RAfABh@b@dCX`CLdA^zB`@~Cd@zB?RQ`@X`@lAvFh@tCZlAPz@b@pBFr@@~@EdAQx@OZd@rCn@vCnApEj@`BTbAL~@R|A@pBEnBEz@GXeAxDaAbASJJZHTHF`AEZ@HHd@bAPh@BROtAKd@Bb@J|@HHhAz@RtBPj@b@lAL|@XbALfAFXb@hBCpAD`@Nz@?x@BvAHj@Ct@FZB`BQ@SAo@K{@IuB?sEHwDTw@H@RJX@~@qCR
//ht tp:/ / s tackoverflow.com/questions/6082440/how-to-parse-google-maps-direction-apis-overview-polyline

2.if you got this encoded string on server side. here is decoder in C# – Saboor Awan

private List<Location> DecodePolylinePoints(string encodedPoints)
            {
                if (encodedPoints == null || encodedPoints == "") return null;
                List<Location> poly = new List<Location>();
                char[] polylinechars = encodedPoints.ToCharArray();
                int index = 0;

                int currentLat = 0;
                int currentLng = 0;
                int next5bits;
                int sum;
                int shifter;
              
                try
                {
                    while (index < polylinechars.Length)
                    {
                        // calculate next latitude                         sum = 0;
                        shifter = 0;
                        do
                        {
                            next5bits = (int)polylinechars[index++] - 63;
                            sum |= (next5bits & 31) << shifter;
                            shifter += 5;
                        } while (next5bits >= 32 && index < polylinechars.Length);

                        if (index >= polylinechars.Length)
                            break;

                        currentLat += (sum & 1) == 1 ? ~(sum >> 1) : (sum >> 1);

                        //calculate next longitude                         sum = 0;
                        shifter = 0;
                        do
                        {
                            next5bits = (int)polylinechars[index++] - 63;
                            sum |= (next5bits & 31) << shifter;
                            shifter += 5;
                        } while (next5bits >= 32 && index < polylinechars.Length);

                        if (index >= polylinechars.Length && next5bits >= 32)
                            break;

                        currentLng += (sum & 1) == 1 ? ~(sum >> 1) : (sum >> 1);
                        Location p = new Location();
                        p.Latitude = Convert.ToDouble(currentLat) / 100000.0;
                        p.Longitude = Convert.ToDouble(currentLng) / 100000.0;
                        poly.Add(p);
                    }
                }
                catch (Exception ex)
                {
                    // logo it                 }
                return poly;
           }

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