Restricting layer rendering to a limited extent.
This example uses the layer.setExtent()
method to modify the extent of the overlay layer. Use the controls below to limit rendering based on an extent.
<!DOCTYPE html>
<html>
<head>
<title>Limited Layer Extent</title>
<script src="https://code.jquery.com/jquery-1.11.2.min.js"></script>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap.min.css">
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/js/bootstrap.min.js"></script>
<link rel="stylesheet" href="http://openlayers.org/en/v3.9.0/css/ol.css" type="text/css">
<script src="http://openlayers.org/en/v3.9.0/build/ol.js"></script>
</head>
<body>
<div class="container-fluid">
<div class="row-fluid">
<div class="span12">
<div id="map" class="map"></div>
</div>
</div>
<div class="btn-group">
<button type="button" class="btn btn-default" id="northwest">northwest</button>
<button type="button" class="btn btn-default" id="northeast">northeast</button>
<button type="button" class="btn btn-default" id="southeast">southeast</button>
<button type="button" class="btn btn-default" id="southwest">southwest</button>
<button type="button" class="btn btn-default" id="world">world</button>
</div>
</div>
<script>
function transform(extent) {
return ol.proj.transformExtent(extent, 'EPSG:4326', 'EPSG:3857');
}
var extents = {
northwest: transform([-180, 0, 0, 85]),
northeast: transform([0, 0, 180, 85]),
southeast: transform([0, -85, 180, 0]),
southwest: transform([-180, -85, 0, 0]),
world: transform([-180, -85, 180, 85])
};
var base = new ol.layer.Tile({
source: new ol.source.TileJSON({
url: 'http://api.tiles.mapbox.com/v3/' +
'mapbox.world-black.jsonp',
crossOrigin: 'anonymous'
})
});
var overlay = new ol.layer.Tile({
extent: extents.northwest,
source: new ol.source.TileJSON({
url: 'http://api.tiles.mapbox.com/v3/' +
'mapbox.world-glass.jsonp',
crossOrigin: 'anonymous'
})
});
var map = new ol.Map({
layers: [base, overlay],
target: 'map',
view: new ol.View({
center: [0, 0],
zoom: 1
})
});
for (var key in extents) {
document.getElementById(key).onclick = function(event) {
overlay.setExtent(extents[event.target.id]);
};
}
</script>
</body>
</html>