ArcGIS 最短路径计算

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
 
 }
}