OpenLayers调用天地图WMTS示例
最近，工作中有需要用OpenLayers脚本库调用天地图的WMTS服务接口，由于这两个都是刚开始接触，所以是摸着石头过河，遇到了地图显示不了的问题。
我也通过用浏览器直接提供的地址打开，来进行参数对比。再看了OpenLayers和天地图的相关文档和网络上的文章，也加入了相关群下载相关资料浏览并询问群友，还是未果。
虽然官网http://www.zjditu.cn/resource/apihelp 有这么一个例子，但是我替换成提供的正式地址，并没有显示地图（每个层级都是需要的，否则只能通过放大或者缩小才能看到，还有layer的值大小写需要匹配）。
最后还是让提供方给了个例子，完成了实现（刚开始要，没给，不知道是忙还是什么情况）。
为了让刚接触这种需求的广大程序猿能够少走点弯路，下面给出示例，有注释。有些参数不懂或者想使用复杂功能的，则查阅下列网址：
OpenLayers官网：https://openlayers.org/
扯淡大叔的教程：http://anzhihun.coding.me/ol3-primer/
示例代码如下：
<!DOCTYPE html>
<html>
<head>
<title></title>
<link rel="stylesheet" href="https://openlayers.org/en/v4.6.4/css/ol.css" type="text/css">
<script src="https://openlayers.org/en/v4.6.4/build/ol.js"></script>
</head>
<body>
<div>
选中的经纬度：
<input id="Coordinates" type="text" value="" disabled="disabled" style="width: 350px;" />
</div>
<div id="map" class="map" style="height: 493px;"></div>
<div id="div_overlay" style="display: none;">
<div id="marker" title="">
<img src="position_orange.png" />
</div>
<div id="popup" title=""></div>
</div>
<script>
var projection = ol.proj.get('EPSG:4326');//设置坐标系
var projectionExtent = projection.getExtent();
//分辨率
var resolutions = [
1.40625,
0.703125,
0.3515625,
0.17578125,
0.087890625,
0.0439453125,
0.02197265625,
0.010986328125,
0.0054931640625,
0.00274658203125,
0.001373291015625,
0.0006866455078125,
0.00034332275390625,
0.000171661376953125,
0.0000858306884765625,
0.00004291534423828125,
0.000021457672119140625,
0.000010728836059570312,
0.000005364418029785156,
0.000002682209014892578,
0.000001341104507446289
];
//瓦片矩阵
var matrixIds = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20];
var centerXY = "121.54449462890625,29.875946044921875";//地图中心点，默认宁波市
var center = ReturnCenter(centerXY);
var emap_attributions = new ol.Attribution({
html: '<span class="span_switch" onclick="ChangeToImgMap()">点击切换地图类型</span>'
});
function EMap() {
var map = new ol.Map({
controls: ol.control.defaults({
attribution: false
}).extend([
new ol.control.MousePosition()//是否显示鼠标所在地图点的经纬度
]),
layers: [
new ol.layer.Tile({
source: new ol.source.WMTS({
attributions: emap_attributions,
name: "中国矢量1-14级",
url: "http://t{0-6}.tianditu.com/vec_c/wmts",
layer: "vec",
style: "default",
matrixSet: "c",
format: "tiles",
wrapX: true,//地图缩小后，防止在一个页面出现多个一样的地图
tileGrid: new ol.tilegrid.WMTS({
origin: ol.extent.getTopLeft(projectionExtent),
resolutions: resolutions.slice(0, 15),//slice方法不清楚的请百度
matrixIds: matrixIds.slice(0, 15)
})
}),
maxResolution: resolutions[0],
minResolution: resolutions[14]
}),
new ol.layer.Tile({
source: new ol.source.WMTS({
attributions: emap_attributions,
name: "中国矢量注记1-14级",
url: "http://t{0-6}.tianditu.com/cva_c/wmts",
layer: "cva",
style: "default",
matrixSet: "c",
format: "tiles",
wrapX: true,
tileGrid: new ol.tilegrid.WMTS({
origin: ol.extent.getTopLeft(projectionExtent),
resolutions: resolutions.slice(0, 15),
matrixIds: matrixIds.slice(0, 15)
})
}),
maxResolution: resolutions[0],
minResolution: resolutions[14]
}),
new ol.layer.Tile({
source: new ol.source.WMTS({
attributions: emap_attributions,
name: "浙江矢量15-17级",
url: "http://srv{0-6}.zjditu.cn/ZJEMAP_2D/wmts",
layer: "TDT_ZJEMAP",
style: "default",
matrixSet: "TileMatrixSet0",
format: "image/png",
wrapX: true,
tileGrid: new ol.tilegrid.WMTS({
origin: ol.extent.getTopLeft(projectionExtent),
resolutions: resolutions.slice(15, 18),
matrixIds: matrixIds.slice(15, 18)
})
}),
maxResolution: resolutions[14],//指定当前级数的上一级来平滑过渡，否则滚轮缩放当前级数会显示空白
minResolution: resolutions[17]
}),
new ol.layer.Tile({
source: new ol.source.WMTS({
attributions: emap_attributions,
name: "浙江矢量注记15-17级",
url: "http://srv{0-6}.zjditu.cn/ZJEMAPANNO_2D/wmts",
layer: "ZJEMAPANNO",
style: "default",
matrixSet: "TileMatrixSet0",
format: "image/png",
wrapX: true,
tileGrid: new ol.tilegrid.WMTS({
origin: ol.extent.getTopLeft(projectionExtent),
resolutions: resolutions.slice(15, 18),
matrixIds: matrixIds.slice(15, 18)
})
}),
maxResolution: resolutions[14],//指定当前级数的上一级来平滑过渡，否则滚轮缩放当前级数会显示空白
minResolution: resolutions[17]
}),
new ol.layer.Tile({
source: new ol.source.WMTS({
attributions: emap_attributions,
name: "XX县矢量18-20级",
url: "替换成你需要的wmts服务接口地址",
layer: "jsemap",
style: "default",
matrixSet: "TileMatrixSet0",
format: "image/png",
wrapX: true,
tileGrid: new ol.tilegrid.WMTS({
origin: ol.extent.getTopLeft(projectionExtent),
resolutions: resolutions.slice(18, 21),
matrixIds: matrixIds.slice(18, 21)
})
}),
maxResolution: resolutions[17],//指定当前级数的上一级来平滑过渡，否则滚轮缩放当前级数会显示空白
minResolution: resolutions[20]
}),
new ol.layer.Tile({
source: new ol.source.WMTS({
attributions: emap_attributions,
name: "XX县矢量注记18-20级",
url: "替换成你需要的wmts服务接口地址",
layer: "jsemapanno",
style: "default",
matrixSet: "TileMatrixSet0",
format: "image/png",
wrapX: true,
tileGrid: new ol.tilegrid.WMTS({
origin: ol.extent.getTopLeft(projectionExtent),
resolutions: resolutions.slice(18, 21),
matrixIds: matrixIds.slice(18, 21)
})
}),
maxResolution: resolutions[17],//指定当前级数的上一级来平滑过渡，否则滚轮缩放当前级数会显示空白
minResolution: resolutions[21]
})
],
target: "map",
view: new ol.View({
center: center,//地图中心点
projection: projection,//投影类别
zoom: 10,//默认缩放级别
maxZoom: 20,//最大缩放级别
minZoom: 1//最小缩放级别
})
});
//鼠标点击时设置中心点覆盖物
GetElementId("map").onclick = function () {
coordinates = GetElementsByClassName('ol-mouse-position')[0].innerHTML;
SetPosition(map, coordinates);
};
}
EMap();//显示E电子地图
function GetElementId(id) {
return document.getElementById(id);
}
function GetElementsByClassName(className) {
return document.getElementsByClassName(className);
}
//中心点处理
function ReturnCenter(centerXY) {
var centerObj = centerXY.split(',');
var centerX = centerObj[0];
var centerY = centerObj[1];
return [parseFloat(centerX), parseFloat(centerY)];//一定要转换下类型，否则拖拽后，地图就消失了
}
//设置中心点覆盖物
function SetPosition(map, coordinates) {
GetElementId("Coordinates").value = coordinates;
var newcenter = ReturnCenter(coordinates);
// Position marker
var marker = new ol.Overlay({
position: newcenter,
positioning: 'bottom-center',
element: document.getElementById('marker'),
stopEvent: false
});
map.addOverlay(marker);
}
</script>
</body>
</html>
可将上述代码直接复制到txt文件中并保存html，即可成功浏览。点击鼠标可以显示覆盖物并把坐标值显示在上面的文本框中。
附上坐标覆盖物图片和效果图：
如果你踩到坑了，没准在我这会有填坑方法哦，虽然可能只是沧海一粟，O(∩_∩)O
