Google Maps add remove Polyline

Question

i've a question about 'removing Polylines' from Google Maps. In this document is explained, how can be added or removed a polyline. (https://developers.google.com/maps/documentation/javascript/examples/polyline-remove?hl=de)

But my situation is a little bit different. I've a 'addPolyline' function, which adds polyline on Google Maps. With this function i can add Polylines, so i can return 'polyline Object', but i can't remove this polyine with same way.

If you click on 'addLines', it can be drawn a line, but if i click on removeLine, it will not be removed.

var map;
var flightPlanCoordinates;

function addPolyline(el){
    polyName = new google.maps.Polyline({
        path: el,
        strokeColor: '#FF0000',
        strokeOpacity: 1.0,
        strokeWeight: 2
  });
   return polyName;
}


function initialize() {
  var mapOptions = {
    zoom: 3,
    center: new google.maps.LatLng(0, -180),
    mapTypeId: google.maps.MapTypeId.TERRAIN
  };

  map = new google.maps.Map(document.getElementById('map-canvas'), mapOptions);

  flightPlanCoordinates = [
    new google.maps.LatLng(37.772323, -122.214897),
    new google.maps.LatLng(21.291982, -157.821856),
    new google.maps.LatLng(-18.142599, 178.431),
    new google.maps.LatLng(-27.46758, 153.027892)
  ];  
}

function addLine(el) {
  el.setMap(map);
}

function removeLine(el) {
  el.setMap(null);
}

google.maps.event.addDomListener(window, 'load', initialize);

Here is Fiddle : http://jsfiddle.net/aldimeola1122/gna00zwb/

How can i achieve that, can you help me? Thanks in advance.

Answer 1

You are creating a new polyline, then removing it.

<input onclick="removeLine(addPolyline(flightPlanCoordinates));" type=button value="Remove line">

If you want to remove the existing polyline, you need to keep a reference to it.

<input onclick="removeLine(polyline);" type=button value="Remove line">
<input onclick="polyline=addLine(addPolyline(flightPlanCoordinates));" type=button value="Add line">

working fiddle

var map;
var flightPlanCoordinates;
var polyline;

function addPolyline(el) {
  polyName = new google.maps.Polyline({
    path: el,
    strokeColor: '#FF0000',
    strokeOpacity: 1.0,
    strokeWeight: 2
  });
  return polyName;
}


function initialize() {
  var mapOptions = {
    zoom: 3,
    center: new google.maps.LatLng(0, -180),
    mapTypeId: google.maps.MapTypeId.TERRAIN
  };

  map = new google.maps.Map(document.getElementById('map-canvas'), mapOptions);

  flightPlanCoordinates = [
    new google.maps.LatLng(37.772323, -122.214897),
    new google.maps.LatLng(21.291982, -157.821856),
    new google.maps.LatLng(-18.142599, 178.431),
    new google.maps.LatLng(-27.46758, 153.027892)
  ];
}

function addLine(el) {
  el.setMap(map);
  return el;
}

function removeLine(el) {
  el.setMap(null);
}

google.maps.event.addDomListener(window, 'load', initialize);

html,
body,
#map-canvas {
  height: 100%;
  margin: 0px;
  padding: 0px
}
#panel {
  position: absolute;
  top: 5px;
  left: 50%;
  margin-left: -180px;
  z-index: 5;
  background-color: #fff;
  padding: 5px;
  border: 1px solid #999;
}

<script src="https://maps.googleapis.com/maps/api/js"></script>
<div id="panel">
  <input onclick="removeLine(polyline);" type=button value="Remove line">
  <input onclick="polyline=addLine(addPolyline(flightPlanCoordinates));" type=button value="Add line">
</div>
<div id="map-canvas"></div>