Google Maps add remove Polyline - google-maps

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>