Style Map¶
Switch between base map styles (Street, Dark, Hybrid) and toggle the Traffic layer on/off as an overlay. For more information about available styles, see Map Style.
Example¶
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>Map SDK</title>
<meta name="viewport" content="initial-scale=1,maximum-scale=1,user-scalable=no" />
<script src='https://unpkg.com/@vietmap/vietmap-gl-js@6.0.1/dist/vietmap-gl.js'></script>
<link rel='stylesheet' href='https://unpkg.com/@vietmap/vietmap-gl-js@6.0.1/dist/vietmap-gl.css' />
<style>
body {
margin: 0;
padding: 0;
}
#map {
position: absolute;
top: 0;
bottom: 0;
width: 100%;
height: 100%;
}
/*layerSwitcherControl*/
.vietmapgl-ctrl-basemaps {
display: flex;
flex-direction: row;
pointer-events: auto;
bottom: 15px;
position: relative;
left: 20px;
}
.vietmapgl-ctrl-basemaps.reverse {
flex-direction: row-reverse;
}
.vietmapgl-ctrl-basemaps.column {
flex-direction: column;
}
.vietmapgl-ctrl-basemaps.column.reverse {
flex-direction: column-reverse;
}
.vietmapgl-ctrl-basemaps .basemap {
width: 90px;
height: 90px;
margin: 2px;
border: 2px solid #ccc;
box-shadow: 0 1px 5px rgba(0, 0, 0, 0.65);
cursor: pointer;
}
.vietmapgl-ctrl-basemaps .basemap.active {
border-color: orange;
box-shadow: 2px 2px 4px #000;
}
.vietmapgl-ctrl-basemaps.closed .basemap {
display: none;
}
.vietmapgl-ctrl-basemaps.closed .basemap.active {
display: block;
border: 2px solid #ccc;
}
</style>
</head>
<body>
<div id="map"></div>
<button id="traffic-toggle" style="position:absolute;top:10px;left:10px;z-index:1;padding:8px 14px;background:#fff;border:2px solid #ccc;border-radius:4px;cursor:pointer;font-size:13px;font-weight:600;">
🚦 Traffic: OFF
</button>
<script>
const API_KEY = "YOUR_API_KEY_HERE";
const baseMaps = {
WHITE: {
img: "./assets/light-vietmap.png",
url: `https://maps.vietmap.vn/maps/styles/tm/style.json?apikey=${API_KEY}`,
},
DARK: {
img: "./assets/dark-vietmap.png",
url: `https://maps.vietmap.vn/maps/styles/dm/style.json?apikey=${API_KEY}`,
},
HYBRID: {
img: "./assets/hybrid-vietmap.png",
url: `https://maps.vietmap.vn/maps/styles/hm/style.json?apikey=${API_KEY}`,
},
};
const map = new vietmapgl.Map({
container: "map",
style: baseMaps["WHITE"].url, // Set initial style
center: [106.66817068179284, 10.803866192772915],
zoom: 9,
});
class LayerSwitcherControl {
constructor(options) {
this._options = { ...options };
this._container = document.createElement("div");
this._container.classList.add(
"vietmapgl-ctrl",
"vietmapgl-ctrl-basemaps",
"closed"
);
this._container.addEventListener("mouseenter", () => {
this._container.classList.remove("closed");
});
this._container.addEventListener("mouseleave", () => {
this._container.classList.add("closed");
});
}
onAdd(map) {
this._map = map;
const basemaps = this._options.basemaps;
Object.keys(basemaps).forEach((layerId) => {
const base = basemaps[layerId];
const basemapContainer = document.createElement("img");
basemapContainer.src = base.img;
basemapContainer.classList.add("basemap");
basemapContainer.dataset.id = layerId;
basemapContainer.addEventListener("click", () => {
const activeElement = this._container.querySelector(".active");
if (activeElement) {
activeElement.classList.remove("active");
}
basemapContainer.classList.add("active");
map.setStyle(base.url); // Set new style
});
this._container.appendChild(basemapContainer);
if (this._options.initialBaseMap === base.url) {
basemapContainer.classList.add("active");
}
});
return this._container;
}
onRemove() {
this._container.parentNode?.removeChild(this._container);
delete this._map;
}
}
// Add the layer switcher control
map.addControl(
new LayerSwitcherControl({
basemaps: baseMaps,
initialBaseMap: baseMaps["WHITE"].url,
}),
"bottom-left"
);
map.addControl(new vietmapgl.NavigationControl());
// Traffic overlay toggle (vector style merge)
let trafficVisible = false;
let trafficStyle = null; // cached after first fetch
let trafficLayerIds = [];
let trafficSourceIds = [];
// Find the first symbol (text/icon) layer so traffic sits below labels
function getFirstSymbolLayerId() {
const layers = map.getStyle().layers || [];
const found = layers.find((l) => l.type === "symbol");
return found ? found.id : undefined;
}
// Apply already-fetched traffic style synchronously
function applyTrafficLayers() {
if (!trafficStyle) return;
trafficSourceIds = [];
trafficLayerIds = [];
Object.entries(trafficStyle.sources || {}).forEach(([id, src]) => {
if (!map.getSource(id)) map.addSource(id, src);
trafficSourceIds.push(id);
});
const beforeId = getFirstSymbolLayerId();
(trafficStyle.layers || []).forEach((layer) => {
if (!map.getLayer(layer.id)) map.addLayer(layer, beforeId);
trafficLayerIds.push(layer.id);
});
}
function removeTrafficLayer() {
trafficLayerIds.forEach((id) => { if (map.getLayer(id)) map.removeLayer(id); });
trafficSourceIds.forEach((id) => { if (map.getSource(id)) map.removeSource(id); });
trafficLayerIds = [];
trafficSourceIds = [];
}
// Re-add synchronously on style.load — no async delay, so layers are never dropped
map.on("style.load", () => {
if (trafficVisible) applyTrafficLayers();
});
document.getElementById("traffic-toggle").addEventListener("click", async () => {
trafficVisible = !trafficVisible;
const btn = document.getElementById("traffic-toggle");
if (trafficVisible) {
// Fetch once, cache for all future style switches
if (!trafficStyle) {
const res = await fetch(`https://maps.vietmap.vn/maps/styles/tf/style.json?apikey=${API_KEY}`);
trafficStyle = await res.json();
}
applyTrafficLayers();
btn.style.borderColor = "orange";
btn.textContent = "🚦 Traffic: ON";
} else {
removeTrafficLayer();
btn.style.borderColor = "#ccc";
btn.textContent = "🚦 Traffic: OFF";
}
});
</script>
</body>
</html>
