SuperMap iClient for Silverlight API聚合ArcGIS server的REST服务
SuperMap iClient for Silverlight API不仅可以对接SuperMap iServerJava6R、SuperMap iServerJava2008、SuperMap ISDotNet6的服务，实现加载其对应的图层，还可以进行扩展实现第三方图层的加载。例如在项目可能用到ArcGIS的REST服务出的图片作为底图，而业务服务用的是SuperMap的，所以就要通过扩展SuperMap iClient for Silverlight API来实现加载ArcGIS的REST服务。
扩展首先要知道：
1、Bounds：图层的地理范围。
2、CRS：当前图层的坐标参考系。坐标参考系使用 EPSG 发布的代表特定椭球体、单位、地理坐标系或投影坐标系的 Well Konwn ID 值（简称 WKID）。多个图层叠加时，该属性必设。
3、TileSize：请求图片的大小。
4、Resolutions：当前图层的分辨率数组。
5、Url：当前图层地址。
这几个属性是必须知道的。
这里我们就用ERSI_StreetMap_World_2D(MapServer)为例。
http://server.arcgisonline.com/ArcGIS/rest/services/ESRI_StreetMap_World_2D/MapServer
在这上面我们可以得到我们想要的所有数据。
扩展类如下：
1 namespace Test
2 {
3 public enum EMapType
4 {
5 Imagery,
6 Street
7 }
8
9 public class TiledESRIOnlineMapsLayer : TiledCachedLayer
10 {
11 private const string ImageryUrl = " http://services.arcgisonline.com/ArcGIS/rest/services/ESRI_Imagery_World_2D/MapServer/tile/{0}/{1}/{2} " ;
12 private const string StreetMapUrl = " http://services.arcgisonline.com/ArcGIS/rest/services/ESRI_StreetMap_World_2D/MapServer/tile/{0}/{1}/{2} " ;
13 // private const string topoUrl = " http://services.arcgisonline.com/ArcGIS/rest/services/NGS_Topo_US_2D/MapServer/tile/ {0}/{1}/{2}";
14 private const int WKID = 4326 ;
15
16 public override string GetTileUrl( int indexX, int indexY, int level)
17 {
18 return string .Format( this .Url, level, indexY, indexX);
19 }
20
21 public override void Initialize()
22 {
23 this .Bounds = new Rectangle2D( - 179.999999 , - 89.999999 , 179.999999 , 89.999999 );
24 this .CRS = new CoordinateReferenceSystem(WKID, Unit.DecimalDegree);
25 this .TileSize = 512 ;
26
27 double res = 0.3515625 ;
28 double [] resolutions = new double [ 16 ];
29 for ( int i = 0 ; i < resolutions.Length; i ++ )
30 {
31 resolutions[i] = res;
32 res *= 0.5 ;
33 }
34 this .Resolutions = resolutions;
35
36 switch ( this .MapType)
37 {
38 case EMapType.Imagery:
39 this .Url = ImageryUrl;
40 break ;
41 case EMapType.Street:
42 this .Url = StreetMapUrl;
43 break ;
44 }
45 base .Initialize();
46 }
47 public EMapType MapType
48 {
49 get { return (EMapType)GetValue(MapTypeProperty); }
50 set { SetValue(MapTypeProperty, value); }
51 }
52
53 public static readonly DependencyProperty MapTypeProperty = DependencyProperty.Register( " MapType " , typeof (EMapType), typeof (TiledESRIOnlineMapsLayer), new PropertyMetadata( new PropertyChangedCallback(OnMapTypePropertyChanged)));
54 private static void OnMapTypePropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
55 {
56 TiledESRIOnlineMapsLayer layer = d as TiledESRIOnlineMapsLayer;
57 if (layer.IsInitialized)
58 {
59 layer.ChangedTileSource();
60 }
61 }
62
63 private void ChangedTileSource()
64 {
65 switch ( this .MapType)
66 {
67 case EMapType.Imagery:
68 this .Url = ImageryUrl;
69 break ;
70 case EMapType.Street:
71 this .Url = StreetMapUrl;
72 break ;
73 }
74 if ( ! base .IsInitialized)
75 {
76 base .Initialize();
77 }
78 else
79 {
80 base .Refresh();
81 }
82 }
83
84 }
85 }
这样这个扩展类就写完了。
用法：
1 < UserControl x:Class = " TestforArcGIS.Test "
2 xmlns = " http://schemas.microsoft.com/winfx/2006/xaml/presentation "
3 xmlns:x = " http://schemas.microsoft.com/winfx/2006/xaml "
4 xmlns:icMapping = " clr-namespace:SuperMap.Web.Mapping;assembly=SuperMap.Web "
5 xmlns:local = " clr-namespace:iClient60ForSilverlight "
6 >
7 < Grid x:Name = " LayoutRoot " Background = " White " >
8 < icMapping:Map x:Name = " MyMap " >
9 < local:TiledArcGISMapsLayer />
10 </ icMapping:Map >
11 </ Grid >
12 </ UserControl >
效果图：
