Arcgis Engine最短路径分析

using System;

using ESRI.ArcGIS.Carto;

using ESRI.ArcGIS.Geometry;

using ESRI.ArcGIS.Geodatabase;

using ESRI.ArcGIS.NetworkAnalysis;

namespace GisEditor

{

 /// <summary>

 /// 最短路径分析

 /// </summary>

 public class ClsPathFinder

 {

  private IGeometricNetwork m_ipGeometricNetwork;

  private IMap m_ipMap;

  private IPointCollection m_ipPoints;

  private IPointToEID m_ipPointToEID;

  private double m_dblPathCost =0;

  private IEnumNetEID m_ipEnumNetEID_Junctions;

  private IEnumNetEID m_ipEnumNetEID_Edges;

  private IPolyline   m_ipPolyline;

  #region Public Function

  //返回和设置当前地图

  public IMap SetOrGetMap

  {

   set{ m_ipMap = value;}

   get{return   m_ipMap;}

  }

  //打开几何数据集的网络工作空间

  public void OpenFeatureDatasetNetwork(IFeatureDataset FeatureDataset)

  {

   CloseWorkspace();  

   if (!InitializeNetworkAndMap(FeatureDataset))

    Console.WriteLine( "打开network出错");

  }

  //输入点的集合

  public IPointCollection StopPoints

  {

   set{m_ipPoints= value;}

   get{return   m_ipPoints;}

  }

  //路径成本

  public double PathCost

  {

   get {return m_dblPathCost;}

  }

  //返回路径的几何体

  public IPolyline PathPolyLine()

  {

   IEIDInfo ipEIDInfo;

   IGeometry ipGeometry;   

   if(m_ipPolyline!=null)return m_ipPolyline;

   m_ipPolyline = new PolylineClass();

   IGeometryCollection ipNewGeometryColl = m_ipPolyline as IGeometryCollection;

   ISpatialReference ipSpatialReference = m_ipMap.SpatialReference;

   IEIDHelper ipEIDHelper = new EIDHelperClass();

   ipEIDHelper.GeometricNetwork = m_ipGeometricNetwork;  

   ipEIDHelper.OutputSpatialReference = ipSpatialReference;

   ipEIDHelper.ReturnGeometries = true;

   IEnumEIDInfo ipEnumEIDInfo = ipEIDHelper.CreateEnumEIDInfo(m_ipEnumNetEID_Edges);

   int count = ipEnumEIDInfo.Count;

   ipEnumEIDInfo.Reset();

   for(int i =0;i<count;i++)

   {

    ipEIDInfo = ipEnumEIDInfo.Next();

    ipGeometry = ipEIDInfo.Geometry;

    ipNewGeometryColl.AddGeometryCollection( ipGeometry as IGeometryCollection);

   }

   return m_ipPolyline;

  }

  //解决路径

  public void SolvePath(string WeightName)

  {

   try

   {  

    int intEdgeUserClassID;

    int intEdgeUserID;

    int intEdgeUserSubID;

    int intEdgeID;

    IPoint ipFoundEdgePoint;

    double dblEdgePercent;    

    /*PutEdgeOrigins方法的第二个参数要求是IEdgeFlag类型的数组,

     * 在VB等其他语言的代码中，只需传人该类型数组的第一个元素即

     * 可，但C#中的机制有所不同，需要作出如下修改：使用

     * ITraceFlowSolverGEN替代ITraceFlowSolver

     */

    ITraceFlowSolverGEN  ipTraceFlowSolver = new TraceFlowSolverClass() as ITraceFlowSolverGEN;

    INetSolver ipNetSolver = ipTraceFlowSolver as INetSolver;

    INetwork ipNetwork = m_ipGeometricNetwork.Network;

    ipNetSolver.SourceNetwork = ipNetwork;

    INetElements ipNetElements = ipNetwork as INetElements;

    int intCount = m_ipPoints.PointCount;

    //定义一个边线旗数组

    IEdgeFlag[] pEdgeFlagList = new EdgeFlagClass[intCount];

    for(int i = 0;i<intCount ;i++)

    {

     INetFlag ipNetFlag = new EdgeFlagClass()as INetFlag;

     IPoint  ipEdgePoint = m_ipPoints.get_Point(i);

     //查找输入点的最近的边线

     m_ipPointToEID.GetNearestEdge(ipEdgePoint, out intEdgeID,out ipFoundEdgePoint, out dblEdgePercent);

     ipNetElements.QueryIDs( intEdgeID, esriElementType.esriETEdge, out intEdgeUserClassID, out intEdgeUserID,out intEdgeUserSubID);

     ipNetFlag.UserClassID = intEdgeUserClassID;

     ipNetFlag.UserID = intEdgeUserID;

     ipNetFlag.UserSubID = intEdgeUserSubID;

     IEdgeFlag pTemp = (IEdgeFlag)(ipNetFlag as IEdgeFlag);

     pEdgeFlagList[i]=pTemp;   

    }

    ipTraceFlowSolver.PutEdgeOrigins(ref pEdgeFlagList);

    INetSchema ipNetSchema = ipNetwork as INetSchema;

    INetWeight ipNetWeight = ipNetSchema.get_WeightByName(WeightName);

    INetSolverWeights ipNetSolverWeights = ipTraceFlowSolver as INetSolverWeights;

    ipNetSolverWeights.FromToEdgeWeight = ipNetWeight;//开始边线的权重

    ipNetSolverWeights.ToFromEdgeWeight = ipNetWeight;//终止边线的权重

    object [] vaRes =new object[intCount-1];

    //通过findpath得到边线和交汇点的集合

    ipTraceFlowSolver.FindPath(esriFlowMethod.esriFMConnected,

     esriShortestPathObjFn.esriSPObjFnMinSum,

     out m_ipEnumNetEID_Junctions,out m_ipEnumNetEID_Edges, intCount-1, ref vaRes);

    //计算元素成本

    m_dblPathCost = 0;

    for (int i =0;i<vaRes.Length;i++)

    {

     double m_Va =(double) vaRes[i];

     m_dblPathCost = m_dblPathCost + m_Va;

    }     

    m_ipPolyline = null;

   }

   catch(Exception ex)

   {

    Console.WriteLine(ex.Message);

   }

  }

  #endregion

  #region Private Function

  //初始化几何网络和地图

  private bool InitializeNetworkAndMap(IFeatureDataset FeatureDataset)

  {

   IFeatureClassContainer ipFeatureClassContainer;

   IFeatureClass ipFeatureClass ;

   IGeoDataset ipGeoDataset;

   ILayer ipLayer ;

   IFeatureLayer ipFeatureLayer;

   IEnvelope ipEnvelope, ipMaxEnvelope ;

   double dblSearchTol;

   INetworkCollection ipNetworkCollection = FeatureDataset as INetworkCollection;

   int count = ipNetworkCollection.GeometricNetworkCount;

   //获取第一个几何网络工作空间

   m_ipGeometricNetwork = ipNetworkCollection.get_GeometricNetwork(0);

   INetwork ipNetwork = m_ipGeometricNetwork.Network;

   if(m_ipMap!=null)

   {

    m_ipMap = new MapClass();

    ipFeatureClassContainer = m_ipGeometricNetwork as IFeatureClassContainer;

    count = ipFeatureClassContainer.ClassCount;

    for(int i =0;i<count;i++)

    {

     ipFeatureClass = ipFeatureClassContainer.get_Class(i);     

     ipFeatureLayer = new FeatureLayerClass();

     ipFeatureLayer.FeatureClass = ipFeatureClass;    

     m_ipMap.AddLayer( ipFeatureLayer);

    }

   }

   count = m_ipMap.LayerCount;

   ipMaxEnvelope = new EnvelopeClass();

   for(int i =0;i<count;i++)

   {

    ipLayer = m_ipMap.get_Layer(i);

    ipFeatureLayer = ipLayer as IFeatureLayer;   

    ipGeoDataset = ipFeatureLayer as IGeoDataset;

    ipEnvelope = ipGeoDataset.Extent;   

    ipMaxEnvelope.Union( ipEnvelope);

   }

   m_ipPointToEID = new PointToEIDClass();

   m_ipPointToEID.SourceMap = m_ipMap;

   m_ipPointToEID.GeometricNetwork = m_ipGeometricNetwork;

   double dblWidth = ipMaxEnvelope.Width;

   double dblHeight = ipMaxEnvelope.Height;

   if( dblWidth > dblHeight)

    dblSearchTol = dblWidth / 100;

   else

    dblSearchTol = dblHeight / 100;

   m_ipPointToEID.SnapTolerance = dblSearchTol;

   return true  ;

  }

  //关闭工作空间           

  private void CloseWorkspace()

  {

   m_ipGeometricNetwork = null;

   m_ipPoints = null;

   m_ipPointToEID = null;

   m_ipEnumNetEID_Junctions = null;

   m_ipEnumNetEID_Edges = null;

   m_ipPolyline = null;

  }

  #endregion

 }

}

备注：

在调用该类时的次序：

ClsPathFinder  m_ipPathFinder;

if(m_ipPathFinder==null)//打开几何网络工作空间

   {

    m_ipPathFinder = new ClsPathFinder();

    ipMap = this.m_ActiveView.FocusMap;

    ipLayer = ipMap.get_Layer(0);

    ipFeatureLayer = ipLayer as IFeatureLayer;

    ipFDB = ipFeatureLayer.FeatureClass.FeatureDataset;

    m_ipPathFinder.SetOrGetMap = ipMap;

    m_ipPathFinder.OpenFeatureDatasetNetwork(ipFDB);

   }

private void ViewMap_OnMouseDown(object sender, ESRI.ArcGIS.MapControl.IMapControlEvents2_OnMouseDownEvent e)//获取地图上鼠标输入的点

  {

   IPoint ipNew ; 

   if( m_ipPoints==null)

   {

    m_ipPoints = new MultipointClass();

    m_ipPathFinder.StopPoints = m_ipPoints;

   }

   ipNew = ViewMap.ActiveView.ScreenDisplay.DisplayTransformation.ToMapPoint(e.x,e.y);

   object o = Type.Missing;

   m_ipPoints.AddPoint(ipNew,ref o,ref o);   

  }

m_ipPathFinder.SolvePath("Weight");//先解析路径

IPolyline ipPolyResult = m_ipPathFinder.PathPolyLine();//最后返回最短路径