ArcGIS二次开发基础教程(13)：网络分析之最近设施分析

最近设施分析

/// <summary>/// Geodatabase function: open work space/// </summary>/// <param name="strGDBName">Input file name</param>/// <returns>Workspace</returns>public IWorkspace OpenWorkspace(string strMDBName){// As Workspace Factories are Singleton objects, they must be instantiated with the Activatorvar workspaceFactory = System.Activator.CreateInstance(System.Type.GetTypeFromProgID("esriDataSourcesGDB.AccessWorkspaceFactory")) as ESRI.ArcGIS.Geodatabase.IWorkspaceFactory;if (!System.IO.File.Exists(strMDBName)){MessageBox.Show("The workspace: " + strMDBName + " does not exist", "Workspace Error");return null;}IWorkspace workspace = null;try{workspace = workspaceFactory.OpenFromFile(strMDBName, 0);}catch (Exception ex){MessageBox.Show("Opening workspace failed: " + ex.Message, "Workspace Error");}return workspace;}/// <summary>/// Geodatabase function: open network dataset/// </summary>/// <param name="workspace">Input workspace</param>/// <param name="strNDSName">Input network dataset name</param>/// <returns>NetworkDataset</returns>public INetworkDataset OpenNetworkDataset(IWorkspace workspace, string featureDatasetName, string strNDSName){// Obtain the dataset container from the workspacevar featureWorkspace = workspace as IFeatureWorkspace;ESRI.ArcGIS.Geodatabase.IFeatureDataset featureDataset = featureWorkspace.OpenFeatureDataset(featureDatasetName);var featureDatasetExtensionContainer = featureDataset as ESRI.ArcGIS.Geodatabase.IFeatureDatasetExtensionContainer;ESRI.ArcGIS.Geodatabase.IFeatureDatasetExtension featureDatasetExtension = featureDatasetExtensionContainer.FindExtension(ESRI.ArcGIS.Geodatabase.esriDatasetType.esriDTNetworkDataset);var datasetContainer3 = featureDatasetExtension as ESRI.ArcGIS.Geodatabase.IDatasetContainer3;// Use the container to open the network dataset.ESRI.ArcGIS.Geodatabase.IDataset dataset = datasetContainer3.get_DatasetByName(ESRI.ArcGIS.Geodatabase.esriDatasetType.esriDTNetworkDataset, strNDSName);return dataset as ESRI.ArcGIS.Geodatabase.INetworkDataset;}/// <summary>/// Geodatabase function: get network dataset/// </summary>/// <param name="networkDataset">Input network dataset</param>/// <returns>DE network dataset</returns> public IDENetworkDataset GetDENetworkDataset(INetworkDataset networkDataset){// Cast from the network dataset to the DatasetComponentIDatasetComponent dsComponent = networkDataset as IDatasetComponent;// Get the data elementreturn dsComponent.DataElement as IDENetworkDataset;}/// <summary>/// Create NASolver and NAContext/// </summary>/// <param name="networkDataset">Input network dataset</param>private void CreateSolverContext(INetworkDataset networkDataset){if (networkDataset == null) return;//Get the Data ElementIDENetworkDataset deNDS = GetDENetworkDataset(networkDataset);INASolver naSolver = new NAClosestFacilitySolverClass();f_NAContext = naSolver.CreateContext(deNDS, naSolver.Name);((INAContextEdit)f_NAContext).Bind(networkDataset, new GPMessagesClass());}/// <summary>/// Create a layer for the network dataset and add it to the map/// </summary>private void AddNetworkDatasetLayerToMap(INetworkDataset networkDataset){INetworkLayer networkLayer = new NetworkLayerClass();workDataset = networkDataset;ILayer layer = networkLayer as ILayer;layer.Name = "CF_ND";axMapControl1.AddLayer(layer);}/// <summary>/// Create a layer from the context and add it to the map/// </summary>private void AddNetworkAnalysisLayerToMap(){ILayer layer = f_NAContext.Solver.CreateLayer(f_NAContext) as ILayer;layer.Name = f_NAContext.Solver.DisplayName;axMapControl1.AddLayer(layer);}private INAContext f_NAContext;//网络分析上下文private IFeatureClass incidentsFeatureClass;//事故点private IFeatureClass facilitiesFeatureClass;//设施点private IGraphicsContainer gra;private IActiveView act;private bool CFNA = false;//分析准备private int incidentsCount = 0;//事故点private int facilitiesCount = 0;//设施点private void 打开网络数据集ToolStripMenuItem2_Click(object sender, EventArgs e){IFeatureWorkspace featureWorkspace = null;INetworkDataset networkDataset1 = null;openFileDialog1.Title = "打开网络数据集";openFileDialog1.Filter = "Peronal GeoDatabase(*.mdb)|*.mdb";if (openFileDialog1.ShowDialog() == DialogResult.OK){try{// Open Geodatabase and network datasetIWorkspace workspace = OpenWorkspace(openFileDialog1.FileName);networkDataset1 = OpenNetworkDataset(workspace, "CF", "CF_ND");featureWorkspace = workspace as IFeatureWorkspace;}catch (Exception ex){System.Windows.Forms.MessageBox.Show("Unable to open dataset. Error Message: " + ex.Message);this.Close();return;}//创建网络上下文CreateSolverContext(networkDataset1);//从工作空间获得用来存储输入点的要素类incidentsFeatureClass = featureWorkspace.OpenFeatureClass("incidents");facilitiesFeatureClass = featureWorkspace.OpenFeatureClass("facilities");//获得道路和节点图层IFeatureClass road = featureWorkspace.OpenFeatureClass("road");IFeatureClass junctions = featureWorkspace.OpenFeatureClass("CF_ND_Junctions");//把以上四个图层全部添加进地图IFeatureLayer layer1 = new FeatureLayerClass();IFeatureClass class1 = incidentsFeatureClass;layer1.FeatureClass = class1;layer1.Name = class1.AliasName;axMapControl1.AddLayer(layer1);IFeatureLayer layer2 = new FeatureLayerClass();IFeatureClass class2 = facilitiesFeatureClass;layer2.FeatureClass = class2;layer2.Name = class2.AliasName;axMapControl1.AddLayer(layer2);IFeatureLayer layer3 = new FeatureLayerClass();layer3.FeatureClass = road;layer3.Name = road.AliasName;axMapControl1.AddLayer(layer3);IFeatureLayer layer4 = new FeatureLayerClass();layer4.FeatureClass = junctions;layer4.Name = junctions.AliasName;axMapControl1.AddLayer(layer4);//添加网络数据集图层和网络分析图层AddNetworkDatasetLayerToMap(networkDataset1);AddNetworkAnalysisLayerToMap();gra = axMapControl1.ActiveView.FocusMap as IGraphicsContainer;act = axMapControl1.ActiveView;axMapControl1.Refresh();}}private void 分析准备ToolStripMenuItem2_Click(object sender, EventArgs e){CFNA = true;//清除输入设施点ITable table = facilitiesFeatureClass as ITable;table.DeleteSearchedRows(null);//清除输入事故点ITable table2 = incidentsFeatureClass as ITable;table2.DeleteSearchedRows(null);//清除网络分析图层设施点INAClass class1 = f_NAContext.NAClasses.get_ItemByName("Facilities") as INAClass;ITable table3 = class1 as ITable;table3.DeleteSearchedRows(null);//清除网络分析图层事故点INAClass class2 = f_NAContext.NAClasses.get_ItemByName("Incidents") as INAClass;ITable table4 = class2 as ITable;table4.DeleteSearchedRows(null);//清楚路线INAClass class3 = f_NAContext.NAClasses.get_ItemByName("CFRoutes") as INAClass;ITable table5 = class3 as ITable;table5.DeleteSearchedRows(null);//清除障碍INAClass class4 = f_NAContext.NAClasses.get_ItemByName("Barriers") as INAClass;ITable table6 = class4 as ITable;table6.DeleteSearchedRows(null);//点号清零facilitiesCount = 0;incidentsCount = 0;//元素清零gra.DeleteAllElements();act.Refresh();//提醒MessageBox.Show("可开始选择点");}private void ChooseIncidents(object sender, IMapControlEvents2_OnMouseDownEvent e){if (CFNA == true)//如果分析准备好了就添加要素点{IPoint pt = new PointClass();pt = act.ScreenDisplay.DisplayTransformation.ToMapPoint(e.x, e.y);IFeature feature = incidentsFeatureClass.CreateFeature();feature.Shape = pt;feature.Store();incidentsCount++;//在地图上显示当前站点数目ITextElement textElement = new TextElementClass();ITextSymbol ts = new TextSymbolClass();IRgbColor color = new RgbColorClass();color.RGB = 38;ts.Color = color;textElement.Symbol = ts;textElement.Text = incidentsCount.ToString();IElement ele = textElement as IElement;ele.Geometry = pt;gra.AddElement(ele, 0);act.Refresh();}}private void ChooseFacilities(object sender, IMapControlEvents2_OnMouseDownEvent e){if (CFNA == true){IPoint pt = new PointClass();pt = act.ScreenDisplay.DisplayTransformation.ToMapPoint(e.x, e.y);IFeature feature = facilitiesFeatureClass.CreateFeature();feature.Shape = pt;feature.Store();facilitiesCount++;ITextElement textElement = new TextElementClass();ITextSymbol ts = new TextSymbolClass();IRgbColor color = new RgbColorClass();color.RGB = 196;ts.Color = color;textElement.Symbol = ts;textElement.Text = facilitiesCount.ToString();IElement ele = textElement as IElement;ele.Geometry = pt;gra.AddElement(ele, 0);act.Refresh();}}/// <summary>/// Set solver settings/// </summary>/// <param name="strNAClassName">NAClass name</param>/// <param name="inputFC">Input feature class</param>public void LoadNANetworkLocations(string strNAClassName, IFeatureClass inputFC){INamedSet classes = f_NAContext.NAClasses;INAClass naClass = classes.get_ItemByName(strNAClassName) as INAClass;// delete existing Locations except if that a barriersnaClass.DeleteAllRows();// Create a NAClassLoader and set the snap tolerance (meters unit)INAClassLoader classLoader = new NAClassLoader();classLoader.Locator = f_NAContext.Locator;((INALocator3)classLoader.Locator).MaxSnapTolerance = 80;classLoader.NAClass = naClass;//Create field map to automatically map fields from input class to NAClassINAClassFieldMap fieldMap = new NAClassFieldMapClass();fieldMap.CreateMapping(naClass.ClassDefinition, inputFC.Fields);classLoader.FieldMap = fieldMap;// Avoid loading network locations onto non-traversable portions of elementsINALocator3 locator = f_NAContext.Locator as INALocator3;locator.ExcludeRestrictedElements = true;locator.CacheRestrictedElements(f_NAContext);//Load Network Locationsint rowsIn = 0;int rowsLocated = 0;IFeatureCursor featureCursor = inputFC.Search(null, true);classLoader.Load((ICursor)featureCursor, null, ref rowsIn, ref rowsLocated);//Message all of the network analysis agents that the analysis context has changed((INAContextEdit)f_NAContext).ContextChanged();}private void 实施分析ToolStripMenuItem2_Click(object sender, EventArgs e){IGPMessages messages = new GPMessagesClass();//加载站点 设施点和事故点LoadNANetworkLocations("Incidents", incidentsFeatureClass);LoadNANetworkLocations("Facilities", facilitiesFeatureClass);f_NAContext.Solver.Solve(f_NAContext, messages, null);//每次实施分析后把输入要素清空ITable table = incidentsFeatureClass as ITable;table.DeleteSearchedRows(null);ITable table2 = facilitiesFeatureClass as ITable;table.DeleteSearchedRows(null);axMapControl1.Refresh();}

还可以将分析结果以文本形式显示出来

//需要一个ListBox控件/// <summary>/// Display analysis results in the list box/// </summary>public void DisplayOutput(){ITable table = m_NAContext.NAClasses.get_ItemByName(OUTPUTCLASSNAME) as ITable;if (table == null){lstOutput.Items.Add("Impossible to get the " + OUTPUTCLASSNAME + " table");}lstOutput.Items.Add("Number facilities found " + table.RowCount(null).ToString());lstOutput.Items.Add("");if (table.RowCount(null) > 0){lstOutput.Items.Add("IncidentID, FacilityID,FacilityRank,Total_Length" );double total_impedance;long incidentID;long facilityID;long facilityRank;ICursor cursor;IRow row;cursor = table.Search(null, false);row = cursor.NextRow();while (row != null){incidentID = long.Parse(row.get_Value(table.FindField("IncidentID")).ToString());facilityID = long.Parse(row.get_Value(table.FindField("FacilityID")).ToString());facilityRank = long.Parse(row.get_Value(table.FindField("FacilityRank")).ToString());total_impedance = double.Parse(row.get_Value(table.FindField("Total_Length")).ToString());lstOutput.Items.Add(incidentID.ToString() + ",\t" + facilityID.ToString() +",\t" + facilityRank.ToString() + ",\t" + total_impedance.ToString("F2"));row = cursor.NextRow();}}

历届GIS应用技能大赛开发题答案点这里，尚在不定期更新中