leaflet

重写openalyers 的方法，加载天地图瓦片数据

by giser · 2019-04-03

将TiandituLayer 加载到OpenLayers.js Grid类后。

OpenLayers.Layer.TiandituLayer = OpenLayers.Class(OpenLayers.Layer.Grid,
		{

			mapType : null,
			mirrorUrls : null,
			topLevel : null,
			bottomLevel : null,

			topLevelIndex : 0,
			bottomLevelIndex : 20,
			topTileFromX : -180,
			topTileFromY : 90,
			topTileToX : 180,
			topTileToY : -270,

			isBaseLayer : true,
             
			initialize : function(name, url, options) {

				options.topLevel = options.topLevel ? options.topLevel
						: this.topLevelIndex;
				options.bottomLevel = options.bottomLevel ? options.bottomLevel
						: this.bottomLevelIndex;
				options.maxResolution = this
						.getResolutionForLevel(options.topLevel);
				options.minResolution = this
						.getResolutionForLevel(options.bottomLevel);
				var newArguments = [ name, url, {}, options ];
				OpenLayers.Layer.Grid.prototype.initialize.apply(this,
						newArguments);
			},

			clone : function(obj) {

				if (obj == null) {
					obj = new OpenLayers.Layer.TDTLayer(this.name, this.url,
							this.options);
				}

				obj = OpenLayers.Layer.Grid.prototype.clone
						.apply(this, [ obj ]);

				return obj;
			},

			getURL : function(bounds) {
				var level = this
						.getLevelForResolution(this.map.getResolution());
				var coef = 360 / Math.pow(2, level);
				var x_num = this.topTileFromX < this.topTileToX ? Math
						.round((bounds.left - this.topTileFromX) / coef) : Math
						.round((this.topTileFromX - bounds.right) / coef);
				var y_num = this.topTileFromY < this.topTileToY ? Math
						.round((bounds.bottom - this.topTileFromY) / coef)
						: Math.round((this.topTileFromY - bounds.top) / coef);

				var type = this.mapType;
				if (type == "EMap") {
					if (level >= 2 && level <= 10) {
						type = "A0512_EMap";
					} else if (level == 11 || level == 12) {
						type = "B0627_EMap1112";
					} else if (level >= 13 && level <= 18) {
						type = "siwei0608";
					}
				}else if(type=="RMap"){
				    if (level >= 2 && level <= 7) {
						type = "sbsm0210";
					} else if (level >= 8 && level <= 10) {
						type = "sbsm0210";
					} else if (level >= 11 && level <= 14) {
						type = "e11";
					}else if (level >= 15 && level <= 18) {
						type = "sbsm1518";
					}
				}
           
				var url = this.url;
				
				if (this.mirrorUrls != null) {
					url = this.selectUrl(x_num, this.mirrorUrls);
				}
              
				return this.getFullRequestString({
					T : type,
					X : x_num,
					Y : y_num,
					L : level
				}, url);
			},
			selectUrl : function(a, b) {
				return b[a % b.length]
			},
			getLevelForResolution : function(res) {
				var ratio = this.getMaxResolution() / res;
				if (ratio < 1)
					return 0;
				for ( var level = 0; ratio / 2 >= 1;) {
					level++;
					ratio /= 2;
				}
				return level;
			},
			getResolutionForLevel : function(level) {
				return 360 / 256 / Math.pow(2, level);
			},
			getMaxResolution : function() {
				return this.getResolutionForLevel(this.topLevelIndex)
			},
			getMinResolution : function() {
				return this.getResolutionForLevel(this.bottomLevelIndex)
			},
			addTile : function(bounds, position) {
				var url = this.getURL(bounds);
				return new OpenLayers.Tile.Image(this, position, bounds, url,
						this.tileSize);
			},

			CLASS_NAME : "OpenLayers.Layer.TiandituLayer"
		});

测试页面

<!DOCTYPE html>
<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0">
    <meta name="apple-mobile-web-app-capable" content="yes">
    <title>OpenLayers Tiled Map Service Example</title>
    <link rel="stylesheet" href="../theme/default/style.css" type="text/css">
    <link rel="stylesheet" href="style.css" type="text/css">
   <script src="../lib/OpenLayers.js"></script>
    <script type="text/javascript">
      
        var map, layer;

        function init(){
		    var extent = new OpenLayers.Bounds(-180.0, -90.0, 180.0, 90.0);
            var tempScales = [295497593.05875003,147748796.52937502,73874398.264687508,36937199.132343754,18468599.566171877];
		    var mapOptions = {
                maxExtent: extent
            };
			var options= {
			    mapType:"EMap",
                topLevel: 3, 
                bottomLevel: 20
				
            };
            map = new OpenLayers.Map("map",mapOptions);
                        
			layer = new OpenLayers.Layer.TiandituLayer("qincy", "http://tile0.tianditu.com/DataServer",options);
            map.addLayer(layer);
            map.addControls([new OpenLayers.Control.MousePosition()]);
			
            map.setCenter(new OpenLayers.LonLat(106,39), 3);
			
        }
      

    </script>
  </head>
  <body onload="init()">


    <div id="map" style="width:1000px;height:500px"></div>


  </body>
</html>

补充问题，由于天地图12级别以后，标注与地图分离，所以要修改下geturldaim

加载两个图层一个图层设置成隐藏。

转载自：https://blog.csdn.net/cnsd007/article/details/84237399

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Tags: leaflet 重写openalyers 的方法，加载天地图瓦片数据

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