Javascript: Polygon not showing on the map

April 14, 2022

Why polygon not showing on the map? I was trying to highlight a specific location using polygon but it is not showing on the map even though there is no error. here is the code:

<!DOCTYPE html>
<html>
<head>
    <meta name="viewport" content="initial-scale=1,maximum-scale=1,user-scalable=no" 
    />
    <link rel="stylesheet" 
href="https://cdnjs.cloudflare.com/ajax/libs/leaflet/1.7.1/leaflet.css" />
<script src="https://cdnjs.cloudflare.com/ajax/libs/leaflet/1.7.1/leaflet.js"> 
</script>
<style>
  #map {position: absolute; top: 0; right: 0; bottom: 0; left: 0;}
</style>
</head>
<body>
<div id="map">
  <a href="https://www.maptiler.com" 
style="position:absolute;left:10px;bottom:10px;z-index:999;"><img 
src="https://api.maptiler.com/resources/logo.svg" alt="MapTiler logo"></a>
</div>
<p><a href="https://www.maptiler.com/copyright/" target="_blank">© MapTiler</a> <a 
href="https://www.openstreetmap.org/copyright" target="_blank">© OpenStreetMap 
contributors</a></p>
<script>
  var map = L.map('map').setView([8.94917, 125.54361], 12);
  L.tileLayer('https://api.maptiler.com/maps/streets/{z}/{x}/{y}.png? 
key=aLd1dKi19JrBFCzDze2p',{
    tileSize: 512,
    zoomOffset: -1,
    minZoom: 1,
    attribution: "\u003ca href=\"https://www.maptiler.com/copyright/\" 
target=\"_blank\"\u003e\u0026copy; MapTiler\u003c/a\u003e \u003ca 
href=\"https://www.openstreetmap.org/copyright\" target=\"_blank\"\u003e\u0026copy; 
OpenStreetMap contributors\u003c/a\u003e",
    crossOrigin: true
  }).addTo(map);
  var polygon = L.polygon([8.94917, 125.54361],[9.00333023, 125.48916626], 
[8.85280991, 125.66551208]).addTo(map);
</script>
</body>
</html>

>Solution :

There are several issues that prevent the map from displaying, and the polygon shape for loading:

some small errors in source, caused by line returns: see browser console to check and correct these. (note these might not exist in your source, but may be caused by line wrapping when copy/pasting the source).
Main issue is that the polygon coordinates should be wrapped in an array, as shown in bold in this example :

var polygon = L.polygon( [ [8.94917, 125.54361],[9.00333023, 125.48916626], [8.85280991, 125.66551208] ] ).addTo(map);