leaflet 基本案例-图层控件：基础图层+业务图层
可执行示例一个，如下：
<!DOCTYPE html>
<html>
<head>
<title>Layers Control Tutorial - Leaflet</title>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<link rel="shortcut icon" type="image/x-icon" href="docs/images/favicon.ico" />
<link rel="stylesheet" href="https://unpkg.com/leaflet@1.6.0/dist/leaflet.css" integrity="sha512-xwE/Az9zrjBIphAcBb3F6JVqxf46+CDLwfLMHloNu6KEQCAWi6HcDUbeOfBIptF7tcCzusKFjFw2yuvEpDL9wQ==" crossorigin=""/>
<script src="https://unpkg.com/leaflet@1.6.0/dist/leaflet.js" integrity="sha512-gZwIG9x3wUXg2hdXF6+rVkLF/0Vi9U8D2Ntg4Ga5I5BZpVkVxlJWbSQtXPSiUTtC0TjtGOmxa1AJPuV0CPthew==" crossorigin=""></script>
<style>
html, body {
height: 100%;
margin: 0;
}
#map {
width: 1000px;
height: 700px;
}
</style>
</head>
<body>
<div id='map'></div>
<script>
//地图marker数组
var markers=[];
var marker1 =L.marker([39.61, -105.02]).bindPopup('This is Littleton, CO.');
var marker2 =L.marker([39.74, -104.99]).bindPopup('This is Denver, CO.');
var marker3 =L.marker([39.73, -104.8]).bindPopup('This is Aurora, CO.');
var marker4 =L.marker([39.77, -105.23]).bindPopup('This is Golden, CO.');
markers.push(marker1);
markers.push(marker2);
markers.push(marker3);
markers.push(marker4);
//利用marker数组构建marker图层
var citiesLayer = L.layerGroup(markers);
//利用切片地图服务地址，创建图层
var grayscaleLayer= L.tileLayer('http://map.geoq.cn/ArcGIS/rest/services/ChinaOnlineCommunity/MapServer/tile/{z}/{y}/{x}',
{id: 'map11'});
var streetsLayer = L.tileLayer('http://map.geoq.cn/ArcGIS/rest/services/ChinaOnlineStreetPurplishBlue/MapServer/tile/{z}/{y}/{x}',
{id: 'map12'});
//1、基础地图
var baseLayers = {
"Grayscale": grayscaleLayer,
"Streets": streetsLayer
};
//1、业务图层
var overLayers = {
"Cities": citiesLayer
};
var map = L.map('map', {
minZoom: 5,
maxZoom: 12,
center: [39.73, -104.99],
zoom: 10,
layers: [grayscaleLayer, citiesLayer],//默认显示的图层
//zoomDelta: 0.5,//点击+-按钮的放缩刻度尺度，默认值1
//zoomSnap: 0.5,//地图能放缩的zoom的最小刻度尺度，默认值1
fullscreenControl: false,//全屏控件，不显示
zoomControl: false,//放大缩小控件，不显示
attributionControl: false//右下角属性控件，不显示
});
//map的图层控件
var layerControl=L.control.layers(baseLayers, overLayers);
map.addControl(layerControl);
//单个图层，也可以通过，map,addLayer()来添加
//map.setView([36.045, 103.83333], 15);//切换地图视野范围
//和setView类似，但是flyTo会带一个平滑的动画
//map.flyTo([36.045, 103.83333], 15,{ animate: true, duration: 0.2 });
//map.setZoom(0);
</script>
</body>
</html>
