扩展TiledMapServiceLayer，加载ArcGIS Server发布的切片地图

来源：互联网发布：中兴手机下载软件编辑：程序博客网时间：2024/05/16 05:24

通常情况下我们直接使用ArcGISTiledMapServiceLayer来加载ArcGIS Server 发布的地图服务。但若我们需自定义一些功能的话，需扩展TiledMapServiceLayer来加载ArcGIS Server发布的切片地图。

下面我们一步一步来实现自定义TiledMapServiceLayer加载ArcGIS Server发布的切片：

首先查看需要加载的地图服务：http://x.x.x.x:8399/arcgis/rest/services/map/MapServer

内容大致如下：

Tile Info:

Height: 256
Width: 256
DPI: 96
Levels of Detail: (# Levels 10)
- Level ID: 0 [ Start Tile, End Tile ]
- Level ID: 1 [ Start Tile, End Tile ]
- Level ID: 2 [ Start Tile, End Tile ]
- Level ID: 3 [ Start Tile, End Tile ]
- Level ID: 4 [ Start Tile, End Tile ]
- Level ID: 5 [ Start Tile, End Tile ]
- Level ID: 6 [ Start Tile, End Tile ]
- Level ID: 7 [ Start Tile, End Tile ]
- Level ID: 8 [ Start Tile, End Tile ]
- Level ID: 9 [ Start Tile, End Tile ]
Format: PNG24
Compression Quality: 0
Origin: X: -400.0
Y: 400.0
Spatial Reference: 4326

Initial Extent:

XMin: 110

YMin: 20

XMax: 112

YMax: 30

Spatial Reference: 4326

Full Extent:

XMin: 110

YMin: 20

XMax: 112

YMax: 30

Spatial Reference: 4326

其中

切片大小

切片原点

切片格式

每一级切片的分辨率、比例尺

地图初始化范围

地图范围

对扩展TiledMapServiceLayer非常重要。

下面我们来扩展TiledMapServiceLayer

package com.css.conponents
{
import com.esri.ags.SpatialReference;
import com.esri.ags.geometry.Extent;
import com.esri.ags.geometry.MapPoint;
import com.esri.ags.layers.supportClasses.LOD;
import com.esri.ags.layers.supportClasses.TileInfo;
import com.esri.ags.layers.TiledMapServiceLayer;

import flash.net.URLRequest;

public class MyMapServiceLayer extends TiledMapServiceLayer
{
  public function MyMapServiceLayer()
  {
   super();
   buildTileInfo(); // to create our hardcoded tileInfo
   setLoaded(true); // Map will only use loaded layers
  }

  private var _tileInfo:TileInfo = new TileInfo(); // see buildTileInfo()
  private var _baseURL:String = "http://x.x.x.x:8399/arcgis/server/arcgiscache/map/Layers/_alllayers";
    // 对应 Initial Extent:
  override public function get fullExtent():Extent
  {
   return new Extent(110, 20, 112, 30, new SpatialReference(4326));
  }
  // 对应 Full Extent:

  override public function get initialExtent():Extent
  {
   return new Extent(110, 20, 112, 30, new SpatialReference(4326));
  }

  override public function get spatialReference():SpatialReference
  {
   return new SpatialReference(4326);
  }

  override public function get tileInfo():TileInfo
  {
   return _tileInfo;
  }
  override protected function getTileURL(level:Number, row:Number, col:Number):URLRequest
  {
    var url:String = _baseURL
    + "/L" + padString(String(level), 2, "0")
    + "/R" + padString(row.toString(16), 8, "0")
    + "/C" + padString(col.toString(16), 8, "0") + ".png";
   return new URLRequest(url);
  }

  private function buildTileInfo():void
  {

  // 对应   Tile Info:height /width :
   _tileInfo.height = 256;
   _tileInfo.width = 256;

  // 对应 Tile Info:Origin :
   _tileInfo.origin = new MapPoint(-400, 400);
   _tileInfo.spatialReference = new SpatialReference(4326);

  // 对应 Tile Info: Levels of Detail:
   _tileInfo.lods =
    [

new LOD(0, 0.0023794610058302797, 1000000.0),
...

     new LOD(9, 4.758922011660559E-6,2000)
    ];
  }

  private function padString(text:String, size:int, ch:String):String
  {
   while (text.length < size)
   {
    text = ch + text;
   }
   return text;
  }
}

}

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