arcgis api for javascipt 加载天地图、百度地图

写在前面的话：

1.百度地图是自己定义的坐标系统，wkid=102100.百度地图数据是加密的产物。下文将附上百度坐标与WGS84，谷歌等坐标系统转换方法（地理-地理），此方法并未亲测，据说准

2.百度地图可以直接加载经纬度坐标

3.百度地图如果加载的arcgis api中会出现坐标偏移，1.中已经解决了地理坐标转换，那么找到百度投影-地理坐标的转换方式，则arcgis就可以直接无偏加载了，网上很多方法，但是亲测不行。

4.天地图不是涉密数据，根据本文提供的类库,arcgis api for js可以直接加载。但是数据有略微的偏移

天地图的切片地图可以通过esri.layers.TiledMapServiceLayer来加载，在此将之进行了一定的封装，如下：

1、切片线划图——TDTLayer.js

define(["dojo/_base/declare",

"esri/layers/tiled"],

function (declare) {

return declare(esri.layers.TiledMapServiceLayer, {

constructor: function () {

this.spatialReference = new esri.SpatialReference({ wkid: 4326 });

this.initialExtent = (this.fullExtent = new esri.geometry.Extent(-180.0, -90.0, 180.0, 90.0, this.spatialReference));

this.tileInfo = new esri.layers.TileInfo({

"rows": 256,

"cols": 256,

"compressionQuality": 0,

"origin": {

"x": -180,

"y": 90

},

"spatialReference": {

"wkid": 4326

},

"lods": [

{ "level": 2, "resolution": 0.3515625, "scale": 147748796.52937502 },

{ "level": 3, "resolution": 0.17578125, "scale": 73874398.264687508 },

{ "level": 4, "resolution": 0.087890625, "scale": 36937199.132343754 },

{ "level": 5, "resolution": 0.0439453125, "scale": 18468599.566171877 },

{ "level": 6, "resolution": 0.02197265625, "scale": 9234299.7830859385 },

{ "level": 7, "resolution": 0.010986328125, "scale": 4617149.8915429693 },

{ "level": 8, "resolution": 0.0054931640625, "scale": 2308574.9457714846 },

{ "level": 9, "resolution": 0.00274658203125, "scale": 1154287.4728857423 },

{ "level": 10, "resolution": 0.001373291015625, "scale": 577143.73644287116 },

{ "level": 11, "resolution": 0.0006866455078125, "scale": 288571.86822143558 },

{ "level": 12, "resolution": 0.00034332275390625, "scale": 144285.93411071779 },

{ "level": 13, "resolution": 0.000171661376953125, "scale": 72142.967055358895 },

{ "level": 14, "resolution": 8.58306884765625e-005, "scale": 36071.483527679447 },

{ "level": 15, "resolution": 4.291534423828125e-005, "scale": 18035.741763839724 },

{ "level": 16, "resolution": 2.1457672119140625e-005, "scale": 9017.8708819198619 },

{ "level": 17, "resolution": 1.0728836059570313e-005, "scale": 4508.9354409599309 },

{ "level": 18, "resolution": 5.3644180297851563e-006, "scale": 2254.4677204799655 }

]

});

this.loaded = true;

this.onLoad(this);

},

getTileUrl: function (level, row, col) {

return "http://t" + col % 8 + ".tianditu.cn/vec_c/wmts?SERVICE=WMTS&REQUEST=GetTile&VERSION=1.0.0&LAYER=vec&STYLE=default&TILEMATRIXSET=c&TILEMATRIX=" + level + "&TILEROW=" + row + "&TILECOL=" + col + "&FORMAT=tiles";

}

});

2、切片标注——TDTAnnoLayer.js