clspathfinder.cs

经典最短路径算法

using System;
using System.Collections.Generic;
using System.Text;
using ESRI.ArcGIS.Carto;
using ESRI.ArcGIS.Geometry;
using ESRI.ArcGIS.Geodatabase;
using ESRI.ArcGIS.NetworkAnalysis;
using ESRI.ArcGIS.DataSourcesGDB;
using System.Windows.Forms;

namespace 最短路径
{
    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;
        private IActiveView m_ipActiveView;
        //返回和设置当前地图
        public IMap SetOrGetMap
        {
            set { m_ipMap = value; }
            get { return m_ipMap; }
        }
        public IActiveView SetOrGetActiveView
        {
            set { m_ipActiveView = value; }
            get { return m_ipActiveView; }
        }
        //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;//引用传递

            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;//这里的points有值吗？
                //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];//我修改过
                    m_dblPathCost = m_dblPathCost + m_Va;
                }
                m_ipPolyline = null;
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }
        }
        //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;
                    for (int j = 0; j < m_ipMap.LayerCount; j++)
                    {
                        if (m_ipMap.get_Layer(j).Name.ToUpper() == ipFeatureLayer.Name.ToUpper())
                        {
                            continue;
                        }
                    }
                    m_ipMap.AddLayer(ipFeatureLayer);
                }
                m_ipActiveView.Refresh();
            }
            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;
        }
        public void OpenAccessNetwork(string AccessFileName, string FeatureDatasetName)
        {
            IWorkspaceFactory ipWorkspaceFactory;
            IWorkspace ipWorkspace;
            IFeatureWorkspace ipFeatureWorkspace;
            IFeatureDataset ipFeatureDataset;
            CloseWorkspace();

           //open the mdb
           ipWorkspaceFactory = new AccessWorkspaceFactory();
           ipWorkspace = ipWorkspaceFactory.OpenFromFile(AccessFileName, 0);

           //et the FeatureWorkspace
           ipFeatureWorkspace = ipWorkspace as IFeatureWorkspace;
  
           //open the FeatureDataset
           ipFeatureDataset = ipFeatureWorkspace.OpenFeatureDataset(FeatureDatasetName);

           //initialize Network and Map (m_ipNetwork, m_ipMap)
           if(InitializeNetworkAndMap(ipFeatureDataset))
           {
               MessageBox.Show("Error!");
           }
        }
    }

}