distance of a polyline

Question

I am working in a polyline and I need to obtain the distance of this. So if anyone can help I would be very gratefully.

Best regards.

This is my code:

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Answer 1

It's easy - using built in functions in the geometry library...

const polyLengthInMeters = google.maps.geometry.spherical.computeLength(yourPolyline.getPath().getArray());

To use the geometry library you declare it when you load the map api

<script type="text/javascript" src="https://maps.googleapis.com/maps/api/js?key={YOUR_KEY}&amp;sensor=false&amp;libraries=geometry"></script>

for more info see:

Google API Polyline reference

Google API mcvArray reference

Google API Spherical geometry reference

Answer 2

The "geometry" library has a computeDistanceBetween method.

This will return the result in meters:

var polylineLength = 0;
for (var i = 0; i < markersPath.length; i++) {
  var lat = parseFloat(markersPath[i].getAttribute("lat"));
  var lng = parseFloat(markersPath[i].getAttribute("lng"));
  var pointPath = new google.maps.LatLng(lat,lng);
  path.push(pointPath);
  if (i > 0) polylineLength += google.maps.geometry.spherical.computeDistanceBetween(path[i], path[i-1]);

}
alert("the length of the polyline is "+polylineLength+" meters");

Update: There is now also a computeLength in the geometry library:

computeLength(path[, radius])
Parameters:
path: Array|MVCArray
radius: number optional
Return Value: number
Returns the length of the given path.

const polyline = new google.maps.Polyline({
    path: polylineCoordinates,
    strokeColor: "#FF0000",
    strokeOpacity: 1.0,
    strokeWeight: 2,
    map: map
  });
var polylineLength = google.maps.geometry.spherical.computeLength(polyline.getPath());

proof of concept fiddle

code snippet:

// This example creates a 2-pixel-wide red polyline showing the path of
// a drive from New York, NY to Newark, NJ
function initMap() {
  const map = new google.maps.Map(document.getElementById("map"),{
  center: {lat:40.71248,lng: -74.006200},
  zoom: 10
  });
  const polyline = new google.maps.Polyline({
    path: polylineCoordinates,
    strokeColor: "#FF0000",
    strokeOpacity: 1.0,
    strokeWeight: 2,
    map: map
  });
  var bounds = new google.maps.LatLngBounds();
  for (var i = 0; i < polyline.getPath().getLength(); i++) {
    console.log(polyline.getPath().getAt(i).toUrlValue(6));
    bounds.extend(polyline.getPath().getAt(i));
  }
  map.fitBounds(bounds);
  var polylineLength = google.maps.geometry.spherical.computeLength(polyline.getPath());
  document.getElementById('info').innerHTML = polylineLength.toFixed(2)+" meters, "+(polylineLength/1000).toFixed(2)+" km, "+(polylineLength/1609).toFixed(2)+" miles";
  console.log(polylineLength.toFixed(2)+" meters, "+(polylineLength/1000).toFixed(2)+" km, "+(polylineLength/1609).toFixed(2)+" miles");
}
// per Google Directions service 13.9 mi. About 31 mins
// 13.9 mi = 22.36988 km
const polylineCoordinates = [
{lat:40.712480,lng:-74.006200},
{lat:40.712450,lng:-74.006150},
{lat:40.712310,lng:-74.005810},
{lat:40.712300,lng:-74.005810},
{lat:40.712300,lng:-74.005800},
{lat:40.712290,lng:-74.005790},
{lat:40.712280,lng:-74.005780},
{lat:40.712260,lng:-74.005770},
{lat:40.712250,lng:-74.005770},
{lat:40.712130,lng:-74.005700},
{lat:40.712130,lng:-74.005700},
{lat:40.712090,lng:-74.005830},
{lat:40.712050,lng:-74.005970},
{lat:40.712020,lng:-74.006090},
{lat:40.711980,lng:-74.006230},
{lat:40.711930,lng:-74.006390},
{lat:40.711930,lng:-74.006440},
{lat:40.711830,lng:-74.006810},
{lat:40.711800,lng:-74.006950},
{lat:40.711770,lng:-74.007050},
{lat:40.711690,lng:-74.007420},
{lat:40.711670,lng:-74.007480},
{lat:40.711660,lng:-74.007510},
{lat:40.711660,lng:-74.007550},
{lat:40.711660,lng:-74.007570},
{lat:40.711660,lng:-74.007600},
{lat:40.711660,lng:-74.007650},
{lat:40.711670,lng:-74.007690},
{lat:40.711680,lng:-74.007710},
{lat:40.711690,lng:-74.007740},
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{lat:40.711750,lng:-74.007840},
{lat:40.711800,lng:-74.007920},
{lat:40.711850,lng:-74.007990},
{lat:40.711870,lng:-74.008010},
{lat:40.711910,lng:-74.008050},
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<!DOCTYPE html>
<html>
  <head>
    <title>Simple Polylines</title>
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