#### Layer Z-Index

Example of ordering layers using Z-index.

There are are two managed layers (square and triangle) and one unmanaged layer (star).
The Z-index determines the rendering order; with {square: 1, triangle: 0, star: unmanaged} indices, the rendering order is triangle, square and star on top.

##### main.js
``````import Feature from 'ol/Feature.js';
import Map from 'ol/Map.js';
import Point from 'ol/geom/Point.js';
import VectorLayer from 'ol/layer/Vector.js';
import VectorSource from 'ol/source/Vector.js';
import View from 'ol/View.js';

const styles = {
square: {
'shape-points': 4,
'shape-angle': Math.PI / 4,
'shape-stroke-color': 'black',
'shape-stroke-width': 1,
'shape-fill-color': 'blue',
},
triangle: {
'shape-points': 3,
'shape-rotation': Math.PI / 4,
'shape-stroke-color': 'black',
'shape-stroke-width': 1,
'shape-fill-color': 'red',
},
star: {
'shape-points': 5,
'shape-rotation': Math.PI / 4,
'shape-stroke-color': 'black',
'shape-stroke-width': 1,
'shape-fill-color': 'green',
},
};

function createLayer(coordinates, style, zIndex) {
const feature = new Feature(new Point(coordinates));

const source = new VectorSource({
features: [feature],
});

const vectorLayer = new VectorLayer({
source: source,
style,
});
vectorLayer.setZIndex(zIndex);

return vectorLayer;
}

const layer0 = createLayer([40, 40], styles.star);
const layer1 = createLayer([0, 0], styles.square, 1);
const layer2 = createLayer([0, 40], styles.triangle, 0);

const layers = [];
layers.push(layer1);
layers.push(layer2);

const map = new Map({
layers: layers,
target: 'map',
view: new View({
center: [0, 0],
zoom: 18,
}),
});

layer0.setMap(map);

function bindInputs(id, layer) {
const idxInput = document.getElementById('idx' + id);
idxInput.onchange = function () {
layer.setZIndex(parseInt(this.value, 10) || 0);
};
idxInput.value = String(layer.getZIndex());
}
bindInputs(1, layer1);
bindInputs(2, layer2);
``````
##### index.html
``````<!DOCTYPE html>
<html lang="en">
<meta charset="UTF-8">
<title>Layer Z-Index</title>
<style>
.map {
width: 100%;
height: 400px;
}
</style>
<body>
<div id="map" class="map"></div>
<div>
<label for="idx1">
<input type="number" id="idx1"></input>
Square layer Z-index
</label></br>

<label for="idx2">
<input type="number" id="idx2"></input>
Triangle layer Z-index
</label>
</div>

<script type="module" src="main.js"></script>
</body>
</html>``````
##### package.json
``````{
"name": "layer-z-index",
"dependencies": {
"ol": "8.1.0"
},
"devDependencies": {
"vite": "^3.2.3"
},
"scripts": {
"start": "vite",
"build": "vite build"
}
}``````