ArcEngine 地图导航 查找路径 经纬度坐标导航 最优路径分析

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需求：依据经纬度坐标。取得两个起点与终点，显示最优路径实现导航。

參考官方样例后。我在arcMap上已实现效果，要求改为代码实现。

实现思路：1、创建路径 2、加入位置 3、求解

代码例如以下：

①    创建路径

public INAContext CreateSolverContext(INetworkDataset networkDataset)
{
    IDENetworkDataset deNDS = GetDENetworkDataset(networkDataset);
    INASolver naSolver = new NARouteSolver();//路径（NAClosestFacilitySolver 近期设施）
    INAContextEdit contextEdit = naSolver.CreateContext(deNDS, naSolver.Name) as INAContextEdit;
    contextEdit.Bind(networkDataset, new GPMessagesClass());
    return contextEdit as INAContext;
}
public IDENetworkDataset GetDENetworkDataset(INetworkDataset networkDataset)
{
    IDatasetComponent dsComponent = networkDataset as IDatasetComponent;
    return dsComponent.DataElement as IDENetworkDataset;
}

调用方法：

ILayer ilayer = MapLayerHelper.GetLayerByName(axMapControl1.Map, "道路_ND");
INetworkDataset networkDataset = (ilayer as INetworkLayer).NetworkDataset;//网络数据集
INAContext m_NAContext = CreateSolverContext(networkDataset);

②    加入位置

/// <summary>
/// 在内存中创建图层
/// </summary>
/// <param name="DataSetName">数据集名称（所建图层名称）</param>
/// <param name="AliaseName">别名</param>
/// <param name="SpatialRef">空间參考</param>
/// <param name="GeometryType">几何类型</param>
/// <param name="PropertyFields">属性字段集合</param>
/// <returns>IfeatureLayer</returns>
public static IFeatureLayer CreateFeatureLayerInMemeory(string DataSetName, string AliaseName, ISpatialReference SpatialRef, esriGeometryType GeometryType, IFields PropertyFields)
{
    ESRI.ArcGIS.Geodatabase.IWorkspaceFactory workspaceFactory = new ESRI.ArcGIS.DataSourcesGDB.InMemoryWorkspaceFactoryClass();
    ESRI.ArcGIS.Geodatabase.IWorkspaceName workspaceName = workspaceFactory.Create("", "MyWorkspace", null, 0);
    ESRI.ArcGIS.esriSystem.IName name = (IName)workspaceName;
    ESRI.ArcGIS.Geodatabase.IWorkspace inmemWor = (IWorkspace)name.Open();
    IField oField = new FieldClass();
    IFields oFields = new FieldsClass();
    IFieldsEdit oFieldsEdit = null;
    IFieldEdit oFieldEdit = null;
    IFeatureClass oFeatureClass = null;
    IFeatureLayer oFeatureLayer = null;
    try
    {
        oFieldsEdit = oFields as IFieldsEdit;
        oFieldEdit = oField as IFieldEdit;
        if (PropertyFields != null)
        {
            for (int i = 0; i < PropertyFields.FieldCount; i++)
            {
                oFieldsEdit.AddField(PropertyFields.get_Field(i));
            }
        }
        IGeometryDef geometryDef = new GeometryDefClass();
        IGeometryDefEdit geometryDefEdit = (IGeometryDefEdit)geometryDef;
        geometryDefEdit.AvgNumPoints_2 = 5;
        geometryDefEdit.GeometryType_2 = GeometryType;
        geometryDefEdit.GridCount_2 = 1;
        geometryDefEdit.HasM_2 = false;
        geometryDefEdit.HasZ_2 = false;
        geometryDefEdit.SpatialReference_2 = SpatialRef;

        oFieldEdit.Name_2 = "SHAPE";
        oFieldEdit.Type_2 = esriFieldType.esriFieldTypeGeometry;
        oFieldEdit.GeometryDef_2 = geometryDef;
        oFieldEdit.IsNullable_2 = true;
        oFieldEdit.Required_2 = true;
        oFieldsEdit.AddField(oField);

        oFeatureClass = (inmemWor as IFeatureWorkspace).CreateFeatureClass(DataSetName, oFields, null, null, esriFeatureType.esriFTSimple, "SHAPE", "");
        (oFeatureClass as IDataset).BrowseName = DataSetName;

        oFeatureLayer = new FeatureLayerClass();
        oFeatureLayer.Name = AliaseName;
        oFeatureLayer.FeatureClass = oFeatureClass;
    }
    catch
    {}
    finally
    {
        System.Runtime.InteropServices.Marshal.ReleaseComObject(oField);
        System.Runtime.InteropServices.Marshal.ReleaseComObject(oFields);
        System.Runtime.InteropServices.Marshal.ReleaseComObject(oFieldsEdit);
        System.Runtime.InteropServices.Marshal.ReleaseComObject(oFieldEdit);
        System.Runtime.InteropServices.Marshal.ReleaseComObject(name);
        System.Runtime.InteropServices.Marshal.ReleaseComObject(workspaceFactory);
        System.Runtime.InteropServices.Marshal.ReleaseComObject(workspaceName);
        System.Runtime.InteropServices.Marshal.ReleaseComObject(inmemWor);
        System.Runtime.InteropServices.Marshal.ReleaseComObject(oFeatureClass);
        GC.Collect();
    }
    return oFeatureLayer;
}

INAClassLoader classLoader = new NAClassLoader();
classLoader.Locator = m_NAContext.Locator;
classLoader.Locator.SnapTolerance = 100;
classLoader.NAClass = m_NAContext.NAClasses.get_ItemByName("Stops") as INAClass;
//加入起点与终点位置
string[] startCoordinate = textBox1.Text.Split(',');
string[] endCoordinate = textBox2.Text.Split(',');
double x1 = SpatialReferenceHelper.ConvertDegreesToDigital(startCoordinate[0]);
double y1 = SpatialReferenceHelper.ConvertDegreesToDigital(startCoordinate[1]);
double x2 = SpatialReferenceHelper.ConvertDegreesToDigital(endCoordinate[0]);
double y2 = SpatialReferenceHelper.ConvertDegreesToDigital(endCoordinate[1]);
IPoint startPoint = new PointClass();
startPoint.PutCoords(x1, y1);
startPoint.SpatialReference = LocateHelper.GeoCoordinateSystem;
startPoint.Project(mainForm.MapForm.axMapControl1.SpatialReference);
IPoint endPoint = new PointClass();
endPoint.PutCoords(x2, y2);
endPoint.SpatialReference = LocateHelper.GeoCoordinateSystem;
endPoint.Project(mainForm.MapForm.axMapControl1.SpatialReference);

IFeatureLayer featurelayer = MapApi.CreateFeatureLayerInMemeory("点图层", "点图层", LocateHelper.GeoCoordinateSystem, esriGeometryType.esriGeometryPoint, null);
IFeature feature = featurelayer.FeatureClass.CreateFeature();
feature.Shape = startPoint;
feature.Store();
feature = featurelayer.FeatureClass.CreateFeature();
feature.Shape = endPoint;
feature.Store();

③    求解（这里建议 try catch 一下）

int rowsIn = 0, rowsLocated = 0;
IFeatureCursor featureCursor = featurelayer.FeatureClass.Search(null, true);
classLoader.Load((ICursor)featureCursor, null, ref rowsIn, ref rowsLocated);
((INAContextEdit)m_NAContext).ContextChanged();

IGPMessages gpMessages = new GPMessagesClass();
m_NAContext.Solver.Solve(m_NAContext, gpMessages, null); //求解

好了，进行到这里的时候就能看到导航效果了。附图一张

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遇到的问题：因为不存在 Network Analyst 许可，操作失败。

參考官方样例 ClosestFacilitySolver 又一次授权就可以

參考资料：

http://resources.arcgis.com/zh-cn/help/main/10.1/index.html#//00470000005w000000

http://download.csdn.net/download/PMC_520/766131

http://blog.csdn.net/chanyinhelv/article/details/15498845