OpenLayers-加载地图数据(Google Map)
除了WMS地图外,OpenLayers可以直接添加Google Map, Microsoft Virtual Earth等地图。
1. 添加google map的key 使用google map的数据需要google map的一个key。OpenLayers的examples里面有一个key,可以直接使用。也可以在https://developers.google.com/maps/signup?hl=zh-cn上获取一个自己的key。
<script src='http://maps.google.com/maps?file=api&v=2&key=ABQIAAAAjpkAC9ePGem0lIq5XcMiuhR_wWLPFku8Ix9i2SXYRVK3e45q1BQUd_beF8dtzKET_EteAjPdGDwqpQ'></script>
2)
2. 创建OpenLayers Google 图层对象
<script type="text/javascript">
var map = null;
function init()
{
//创建map对象,
map = new OpenLayers.Map("map");
map.addControl(new OpenLayers.Control.LayerSwitcher());
//创建google Map图层对象
var gphy = new OpenLayers.Layer.Google(
"Google Physical", //Google Map Physical图层
{type: G_PHYSICAL_MAP}
);
var gmap = new OpenLayers.Layer.Google(
"Google Streets", //Google Map Streets图层
{numZoomLevels: 20} //设置Google Map的zoom级别
);
var ghyb = new OpenLayers.Layer.Google(
"Google Hybrid", //Google Physical图层
{type: G_HYBRID_MAP, numZoomLevels: 20}
);
var gsat = new OpenLayers.Layer.Google(
"Google Satellite", //Google Map Satellite图层
{type: G_SATELLITE_MAP, numZoomLevels: 22}
);
// 添加图层
map.addLayers([gphy, gmap, ghyb, gsat]);
// 放大到全屏
map.zoomToMaxExtent();
}
</script>
3. 设置html的onload函数
<BODY onload="init()">
然后打开网页就可以看到OpenLayers加载的Google Map地图。通过右侧的Layer Switch可以切换图层。
完整的代码如下所示:
1 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
2 <HTML>
3 <HEAD>
4 <TITLE> Google Map </TITLE>
5 <link rel="stylesheet" href="./OpenLayers-2.10/theme/default/style.css" type="text/css" />
6 <link rel="stylesheet" href="css/style.css" type="text/css" />
7 <script src="./OpenLayers-2.10/lib/OpenLayers.js"></script>
8 <script src='http://maps.google.com/maps?file=api&v=2&key=ABQIAAAAjpkAC9ePGem0lIq5XcMiuhR_wWLPFku8Ix9i2SXYRVK3e45q1BQUd_beF8dtzKET_EteAjPdGDwqpQ'></script>
9 <script type="text/javascript">
10
11 var map = null;
12 function init()
13 {
14 //创建map对象,
15 map = new OpenLayers.Map("map");
16 map.addControl(new OpenLayers.Control.LayerSwitcher());
17
18 //创建google Map图层对象
19 var gphy = new OpenLayers.Layer.Google(
20 "Google Physical", //Google Map Physical图层
21 {type: G_PHYSICAL_MAP}
22 );
23 var gmap = new OpenLayers.Layer.Google(
24 "Google Streets", //Google Map Streets图层
25 {numZoomLevels: 20} //设置Google Map的zoom级别
26 );
27 var ghyb = new OpenLayers.Layer.Google(
28 "Google Hybrid", //Google Physical图层
29 {type: G_HYBRID_MAP, numZoomLevels: 20}
30 );
31 var gsat = new OpenLayers.Layer.Google(
32 "Google Satellite", //Google Map Satellite图层
33 {type: G_SATELLITE_MAP, numZoomLevels: 22}
34 );
35
36 // 添加图层
37 map.addLayers([gphy, gmap, ghyb, gsat]);
38 // 放大到全屏
39 map.zoomToMaxExtent();
40 }
41 </script>
42
43 </HEAD>
44
45 <BODY onload="init()">
46 <div id="map" class="smallmap"></div>
47 </BODY>
48 </HTML>
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