Example of two WMS layers using the projection EPSG:21781, which is unknown to the client.
As long as no coordinate transformations are required, OpenLayers works fine with projections that are only configured with a code
and units
.
<!DOCTYPE html>
<html>
<head>
<title>WMS without Projection</title>
<link rel="stylesheet" href="https://openlayers.org/en/v4.6.4/css/ol.css" type="text/css">
<!-- The line below is only needed for old environments like Internet Explorer and Android 4.x -->
<script src="https://cdn.polyfill.io/v2/polyfill.min.js?features=requestAnimationFrame,Element.prototype.classList,URL"></script>
<script src="https://openlayers.org/en/v4.6.4/build/ol.js"></script>
</head>
<body>
<div id="map" class="map"></div>
<script>
var layers = [
new ol.layer.Tile({
source: new ol.source.TileWMS({
attributions: '© <a href="http://www.geo.admin.ch/internet/geoportal/' +
'en/home.html">Pixelmap 1:1000000 / geo.admin.ch</a>',
crossOrigin: 'anonymous',
params: {
'LAYERS': 'ch.swisstopo.pixelkarte-farbe-pk1000.noscale',
'FORMAT': 'image/jpeg'
},
url: 'https://wms.geo.admin.ch/'
})
}),
new ol.layer.Image({
source: new ol.source.ImageWMS({
attributions: '© <a href="http://www.geo.admin.ch/internet/geoportal/' +
'en/home.html">National parks / geo.admin.ch</a>',
crossOrigin: 'anonymous',
params: {'LAYERS': 'ch.bafu.schutzgebiete-paerke_nationaler_bedeutung'},
serverType: 'mapserver',
url: 'https://wms.geo.admin.ch/'
})
})
];
// A minimal projection object is configured with only the SRS code and the map
// units. No client-side coordinate transforms are possible with such a
// projection object. Requesting tiles only needs the code together with a
// tile grid of Cartesian coordinates; it does not matter how those
// coordinates relate to latitude or longitude.
var projection = new ol.proj.Projection({
code: 'EPSG:21781',
units: 'm'
});
var map = new ol.Map({
layers: layers,
target: 'map',
view: new ol.View({
center: [660000, 190000],
projection: projection,
zoom: 9
})
});
</script>
</body>
</html>