本文基于腾讯课堂老胡的课《跟我学Openlayers--基础实例详解》做的学习笔记，使用的openlayers 5.3.x api。
源码 见 1024.html ，对应的 官网示例 https://openlayers.org/en/latest/examples/layer-extent.html?q=setExtent
image.png
<!DOCTYPE html>
<html>
<head>
<title>按限定范围加载图层
</title>
<link rel="stylesheet" href="../include/ol.css" type="text/css">
<script src="../include/ol.js"></script>
<script src="../include/jquery-3.1.1.min.js"></script>
</head>
<style>
</style>
<body>
<div>
<button type="button" class="btn btn-default" id="India">印度</button>
<button type="button" class="btn btn-default" id="Argentina">阿根廷</button>
<button type="button" class="btn btn-default" id="Nigeria">尼日利亚</button>
<button type="button" class="btn btn-default" id="Sweden">瑞典</button>
<div id="map" class="map"></div>
<script>
function transform(extent) {
return ol.proj.transformExtent(extent, 'EPSG:4326', 'EPSG:3857');
}
var extents = {
India: transform([68.17665, 7.96553, 97.40256, 35.49401]),
Argentina: transform([-73.41544, -55.25, -53.62835, -21.83231]),
Nigeria: transform([2.6917, 4.24059, 14.57718, 13.86592]),
Sweden: transform([11.02737, 55.36174, 23.90338, 69.10625])
};
var base = new ol.layer.Tile({
source: new ol.source.TileJSON({
url: 'https://api.tiles.mapbox.com/v4/mapbox.world-light.json?secure&access_token=pk.eyJ1IjoiYWhvY2V2YXIiLCJhIjoiY2pzbmg0Nmk5MGF5NzQzbzRnbDNoeHJrbiJ9.7_-_gL8ur7ZtEiNwRfCy7Q',
crossOrigin: 'anonymous'
})
});
//覆盖图
var overlay = new ol.layer.Tile({
extent: extents.India,
source: new ol.source.TileJSON({
url: 'https://api.tiles.mapbox.com/v4/mapbox.world-black.json?secure&access_token=pk.eyJ1IjoiYWhvY2V2YXIiLCJhIjoiY2pzbmg0Nmk5MGF5NzQzbzRnbDNoeHJrbiJ9.7_-_gL8ur7ZtEiNwRfCy7Q',
crossOrigin: 'anonymous'
})
});
var map = new ol.Map({
layers: [base, overlay],
target: 'map',
view: new ol.View({
center: [0, 0],
zoom: 1
})
});
//遍历显示限制地图数组，当按钮单击的时候，设置图层TileJSON的边界
for (var key in extents) {
document.getElementById(key).onclick = function (event) {
overlay.setExtent(extents[event.target.id]);
};
}
</script>
</body>
</html>
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