Openlayers示例11 | CartoDB source example
两个图层，一个是底图，另外一个图层是根据条件查询显示地图范围。
<!DOCTYPE html>
<html lang="zn">
<head>
<meta charset="UTF-8">
<!-- 引入OpenLayers CSS样式 -->
<link rel="stylesheet"
href="https://cdn.jsdelivr.net/gh/openlayers/openlayers.github.io@master/en/v6.13.0/css/ol.css">
<!-- 引入OpenLayers JS库 -->
<script src="https://cdn.jsdelivr.net/gh/openlayers/openlayers.github.io@master/en/v6.13.0/build/ol.js"></script>
<!-- css代码 -->
<style>
.map {
width: 100%;
height: 500px;
}
</style>
<title>CartoDB source example</title>
</head>
<body>
<div class="row-fluid">
<div class="span12">
<div id="map" class="map"></div>
<div>
<form class="form-horizontal">
<label>
Show countries larger than
<select id="country-area" class="form-control">
<option value="0" default>0 ㎢</option>
<option value="5000">5000 ㎢</option>
<option value="10000">10000 ㎢</option>
<option value="50000">50000 ㎢</option>
<option value="100000">100000 ㎢</option>
</select>
</label>
</form>
</div>
</div>
</body>
<script>
const mapConfig = {
'layers': [
{
'type': 'cartodb',
'options': {
'cartocss_version': '2.1.1',
'cartocss': '#layer { polygon-fill: #F00; }',
'sql': 'select * from european_countries_e where area > 0',
},
},
],
};
const cartoDBSource = new ol.source.CartoDB({
account: 'documentation',
config: mapConfig,
});
const map = new ol.Map({
layers: [
new ol.layer.Tile({
source: new ol.source.OSM(),
}),
new ol.layer.Tile({
source: cartoDBSource,
}),
],
target: 'map',
view: new ol.View({
center: [0, 0],
zoom: 2,
}),
});
function setArea(n) {
mapConfig.layers[0].options.sql =
'select * from european_countries_e where area > ' + n;
cartoDBSource.setConfig(mapConfig);
}
document.getElementById('country-area').addEventListener('change', function () {
setArea(this.value);
});
</script>
</html>
