Openlayers3加载天地图

概述：

在前文中分别讲到了在Arcgis for js、Openlayers2中去加载天地图，同时也讲到了天地图的离线加载方式。在本文，讲述在Openlayers3中实现在线/离线的天地图的加载。

实现：

直接贴代码吧，效果就不贴了

<script type="text/javascript" src="../../../../plugin/ol3/build/ol-debug.js"></script><script type="text/javascript" src="../../../../plugin/jquery/jquery-1.8.3.js"></script><script type="text/javascript"> var map; function init(){ var bounds = [73.4510046356223, 18.1632471876417, 134.976797646506, 53.5319431522236]; var projection = new ol.proj.Projection({ code: 'EPSG:4326', units: 'degrees' }); var vec_c = getTdtLayer("vec_c"); var cva_c = getTdtLayer("cva_c"); var wms = new ol.layer.Image({ source: new ol.source.ImageWMS({ ratio: 1, url: 'https://localhost:8088/geoserver/lzugis/wms', params: { 'FORMAT': 'image/png', 'VERSION': '1.1.1', LAYERS: 'lzugis:capital', STYLES: '' } }) }); var map = new ol.Map({ controls: ol.control.defaults({ attribution: false }), target: 'map', layers: [vec_c,cva_c,wms], view: new ol.View({ projection: projection, minZoom:2, maxZoom:8 }) }); map.getView().fitExtent(bounds, map.getSize()); } function getTdtLayer(lyr){ var url = "https://localhost:8081/lzugis/tdttile?T="+lyr+"&X={x}&Y={y}&L={z}"; // var url = "https://t0.tianditu.com/DataServer?T="+lyr+"&X={x}&Y={y}&L={z}";在线 var projection = ol.proj.get("EPSG:4326"); var projectionExtent = [ -180, -90, 180, 90 ]; var maxResolution = (ol.extent.getWidth(projectionExtent) / (256 * 2)); var resolutions = new Array(16); var z; for (z = 0; z