ArcGIS Server 中栅格数据的查询。

 本例是想获取dem数据中的某点的高程值。有两种方法可以实现，一种是用ADF 来实现，另外一种就是通过AO来实现了。

（其中对象pt就是要查询的点）

《1》ADF方法

//获取栅格地图资源  

ESRI.ArcGIS.ADF.Web.DataSources.IMapFunctionality func = map.GetFunctionality("DEM");
          

 ESRI.ArcGIS.ADF.Web.DataSources.IGISResource gisRes = func.Resource;
           bool supp = gisRes.SupportsFunctionality(typeof(ESRI.ArcGIS.ADF.Web.DataSources.IQueryFunctionality));
           DataTable[] dt = new DataTable[1];
           int m_IdentifyTolerance = 2;
           IdentifyOption m_idOption = IdentifyOption.VisibleLayers;
           if (supp)
           {
               ESRI.ArcGIS.ADF.Web.DataSources.IQueryFunctionality qfunc = (ESRI.ArcGIS.ADF.Web.DataSources.IQueryFunctionality)gisRes.CreateFunctionality(typeof(ESRI.ArcGIS.ADF.Web.DataSources.IQueryFunctionality), null);
               if (qfunc != null && qfunc.Supports("identify"))
               {
                   try
                   {
                       dt = qfunc.Identify(func.Name, pt, m_IdentifyTolerance, m_idOption, null);//dt即为查询结果
                   }
                   catch
                   {

                   }

               }

           }

            string h=dt.tables[0][1].toString();  //h即为所要查询的高程值

《2》AO方法

          //因地图资源与开发不在同一机器上，因而首先连接远程地图服务。

                  ESRI.ArcGIS.ADF.Identity id = new ESRI.ArcGIS.ADF.Identity();
                    id.UserName =  "Administrator" ;           

                      id.Password = "123456";
                    id.Domain = "gis2_trq";
                    string domainstr = "10.150.38.34";

                    ESRI.ArcGIS.ADF.Connection.AGS.AGSServerConnection agsconn = new ESRI.ArcGIS.ADF.Connection.AGS.AGSServerConnection(domainstr, id);
                    agsconn.Connect();
                    if (!agsconn.IsConnected)
                    {
                        agsconn.Dispose();
                        return "";
                    }
                    ESRI.ArcGIS.Server.IServerObjectManager som = agsconn.ServerObjectManager;
                    string servertype = "MapServer";

                     //获取dem地图资源
                    string serverobjectname1 = "DEM_12503";
                    ESRI.ArcGIS.Server.IServerContext sc1 = som.CreateServerContext(serverobjectname1, servertype);
                    IMapServer pMapServer1 = sc1.ServerObject as IMapServer;
                    IMapServerObjects pMapServerObjs1 = pMapServer1 as IMapServerObjects;
                    IMap pMap1 = pMapServerObjs1.get_Map(pMapServer1.DefaultMapName);

                    IRasterLayer pRLayer = pMap1.get_Layer(0) as IRasterLayer;
                    //IRaster pRaster = pRLayer.Raster as IRaster;
                    ESRI.ArcGIS.Geometry.IPoint pt1 = sc1.CreateObject("esriGeometry.Point") as ESRI.ArcGIS.Geometry.IPoint;
                    pt1.X = pt.X;
                    pt1.Y = pt.Y;
                    IIdentify identify = (IIdentify)pRLayer;
                    IArray pIDArray = identify.Identify(pt1);
                    string HVal = String.Empty;
                    if (pIDArray != null)
                    {
                        IRasterIdentifyObj pRasObj = (IRasterIdentifyObj)pIDArray.get_Element(0);
                        HVal = pRasObj.Name;
                    }

            HVal 就是所要的特定点的高程值（转换成double类型就好了）。