ArcEngine中的空间参考操作代码

GIS中的坐标系一般分为地理坐标系和投影坐标系。地理坐标系就是用经纬度来表示位置，投影坐标系则是按照一定的数学规则，将球体投影到平面上，一般用X、Y表示位置，单位为米。若要进行投影转换，如果转换前和转换后的空间参考是基于同一参考椭球体，则可在ArcGIS中直接进行转换，如果转换前和转换后的空间参考基于不同的参考椭球体，则首先需要计算七参数，然后才能在ArcGIS中进行转换。下面是ArcEngine中关于ISpatialReference的部分操作代码：

using System;
using System.Collections.Generic;
using System.Text;
using ESRI.ArcGIS.Carto;
using ESRI.ArcGIS.DataSourcesFile;
using ESRI.ArcGIS.DataSourcesGDB;
using ESRI.ArcGIS.Display;
using ESRI.ArcGIS.esriSystem;
using ESRI.ArcGIS.Geodatabase;
using ESRI.ArcGIS.Geometry;
using ESRI.ArcGIS.Output;
using ESRI.ArcGIS.SystemUI;

namespace EngineConsoleApplication1
{
    class Program
    {
        private static LicenseInitializer m_AOLicenseInitializer = new EngineConsoleApplication1.LicenseInitializer();

        [STAThread()]
        static void Main(string[] args)
        {
            m_AOLicenseInitializer.InitializeApplication(new esriLicenseProductCode[] { esriLicenseProductCode.esriLicenseProductCodeEngine }, new esriLicenseExtensionCode[] { });
            m_AOLicenseInitializer.ShutdownApplication();

            // 根据prj文件获取空间参考
            ISpatialReference pSpatialReference = GetSpatialReference(@"E:\Users\dsf\Desktop\data\a.prj");
            Console.WriteLine(pSpatialReference.Name);
            Console.WriteLine("---------------------------");

            // 根据要素类获取空间参考
            IFeatureClass pFeatureClass = GetFeatureClass(@"E:\Users\dsf\Desktop\data\b.shp");
            pSpatialReference = GetSpatialReference(pFeatureClass);
            Console.WriteLine(pSpatialReference.Name);
            Console.WriteLine("---------------------------");

            // 创建地理坐标系
            pSpatialReference = GetSpatialReference(esriSRGeoCSType.esriSRGeoCS_WGS1984);
            Console.WriteLine(pSpatialReference.Name);
            Console.WriteLine("---------------------------");

            // 创建投影坐标系
            pSpatialReference = GetSpatialReference(esriSRProjCSType.esriSRProjCS_Beijing1954GK_13N);
            Console.WriteLine(pSpatialReference.Name);
            Console.WriteLine("---------------------------");

            // 定义投影
            pFeatureClass = GetFeatureClass(@"E:\Users\dsf\Desktop\data\c.shp");
            pSpatialReference = GetSpatialReference(esriSRGeoCSType.esriSRGeoCS_WGS1984);
            bool ok = DefineProjection(pFeatureClass, pSpatialReference);
            if (ok)
            {
                Console.WriteLine("定义投影成功");
            }
            else
            {
                Console.WriteLine("定义投影失败");
            }
            Console.WriteLine("---------------------------");

            // 同一基准面下的坐标系转换
            ConvertProjection();
            Console.WriteLine("---------------------------");

            // 获取投影信息\
            GetSpatialReferenceInfo(pSpatialReference);
            Console.ReadKey();
        }

        // 根据prj文件获取空间参考
        static ISpatialReference GetSpatialReference(string filePath)
        {
            ISpatialReferenceFactory pSpatialReferenceFactory = new SpatialReferenceEnvironment();
            ISpatialReference pSpatialReference = pSpatialReferenceFactory.CreateESRISpatialReferenceFromPRJFile(filePath);
            return pSpatialReference;
        }

        // 根据要素类获取空间参考
        static ISpatialReference GetSpatialReference(IFeatureClass pFeatureClass)
        {
            IGeoDataset pGeoDataset = pFeatureClass as IGeoDataset;
            ISpatialReference pSpatialReference = pGeoDataset.SpatialReference;
            return pSpatialReference;
        }

        // 创建地理坐标系
        static ISpatialReference GetSpatialReference(esriSRGeoCSType type)
        {
            ISpatialReferenceFactory pSpatialReferenceFactory = new SpatialReferenceEnvironment();
            ISpatialReference pSpatialReference = pSpatialReferenceFactory.CreateGeographicCoordinateSystem((int)type);
            return pSpatialReference;
        }

        // 创建投影坐标系
        static ISpatialReference GetSpatialReference(esriSRProjCSType type)
        {
            ISpatialReferenceFactory pSpatialReferenceFactory = new SpatialReferenceEnvironment();
            ISpatialReference pSpatialReference = pSpatialReferenceFactory.CreateProjectedCoordinateSystem((int)type);
            return pSpatialReference;
        }

        // 定义空间参考
        static bool DefineProjection(IFeatureClass pFeatureClass, ISpatialReference pSpatialReference)
        {
            IGeoDataset pGeoDataset = pFeatureClass as IGeoDataset;
            IGeoDatasetSchemaEdit pGeoDatasetSchemaEdit = pGeoDataset as IGeoDatasetSchemaEdit;
            if (pGeoDatasetSchemaEdit.CanAlterSpatialReference)
            {
                pGeoDatasetSchemaEdit.AlterSpatialReference(pSpatialReference);
                return true;
            }
            else
            {
                return false;
            }
        }

        // 同一基准面下的坐标系转换
        static void ConvertProjection()
        {
            ISpatialReferenceFactory pSpatialReferenceFactory = new SpatialReferenceEnvironment();
            ISpatialReference pFromSpatialReference = pSpatialReferenceFactory.CreateGeographicCoordinateSystem(4326);
            ISpatialReference pToSpatialReference = pSpatialReferenceFactory.CreateProjectedCoordinateSystem(3395);

            // 设置坐标
            IPoint pPoint = new ESRI.ArcGIS.Geometry.Point();
            pPoint.SpatialReference = pFromSpatialReference;
            pPoint.X = 30;
            pPoint.Y = 30;

            // 地理坐标转换为投影坐标
            pPoint.Project(pToSpatialReference);
            Console.WriteLine(pPoint.X + "," + pPoint.Y);

            // 投影坐标转换为地理坐标
            pPoint.Project(pFromSpatialReference);
            Console.WriteLine(pPoint.X + "," + pPoint.Y);
        }

        // 不同基准面下的坐标系转换
        static void ConvertProjection(IPoint pPoint, double dx, double dy, double dz, double rx, double ry, double rz, double s)
        {
            ISpatialReferenceFactory pSpatialReferenceFactory = new SpatialReferenceEnvironment();
            ISpatialReference pFromSpatialReference = pSpatialReferenceFactory.CreateGeographicCoordinateSystem(2384);  // Xian_1980_3_Degree_GK_CM_117E
            ISpatialReference pToSpatialReference = pSpatialReferenceFactory.CreateProjectedCoordinateSystem(3395);     // Beijing_1954_GK_Zone_19N

            // 设置七参数
            IGeoTransformation pGeoTransformation = new CoordinateFrameTransformation() as IGeoTransformation;
            ICoordinateFrameTransformation pCoordinateFrameTransformation = pGeoTransformation as ICoordinateFrameTransformation;
            pCoordinateFrameTransformation.PutSpatialReferences(pFromSpatialReference, pToSpatialReference);
            pCoordinateFrameTransformation.PutParameters(dx, dy, dz, rx, ry, rz, s);

            // 投影转换
            IGeometry2 pGeometry = pPoint as IGeometry2;
            pGeometry.SpatialReference = pFromSpatialReference;
            pGeometry.ProjectEx(pToSpatialReference, esriTransformDirection.esriTransformForward, pGeoTransformation, false, 0, 0);
        }

        // 空间参考信息
        static void GetSpatialReferenceInfo(ISpatialReference pSpatialReference)
        {
            if (pSpatialReference is IProjectedCoordinateSystem)
            {
                IProjectedCoordinateSystem2 pProjectedCoordinateSystem = pSpatialReference as IProjectedCoordinateSystem2;
                Console.WriteLine(pProjectedCoordinateSystem.FalseNorthing);
                Console.WriteLine(pProjectedCoordinateSystem.FalseEasting);
                Console.WriteLine(pProjectedCoordinateSystem.CentralMeridian[true]);
                Console.WriteLine(pProjectedCoordinateSystem.ScaleFactor);
                Console.WriteLine(pProjectedCoordinateSystem.LatitudeOfOrigin);
                Console.WriteLine(pProjectedCoordinateSystem.GeographicCoordinateSystem.Datum.Spheroid.Name);
                Console.WriteLine(pProjectedCoordinateSystem.Projection.Name);
            }
            else
            {
                IGeographicCoordinateSystem pGeographicCoordinateSystem = pSpatialReference as IGeographicCoordinateSystem;
                Console.WriteLine(pGeographicCoordinateSystem.Datum.Name);
                Console.WriteLine(pGeographicCoordinateSystem.Datum.Spheroid.Name);
                Console.WriteLine(pGeographicCoordinateSystem.Datum.Spheroid.SemiMajorAxis);
                Console.WriteLine(pGeographicCoordinateSystem.Datum.Spheroid.SemiMinorAxis);
                Console.WriteLine(pGeographicCoordinateSystem.Datum.Spheroid.Flattening);                        
            }
        }

        // 获取要素类
        static IFeatureClass GetFeatureClass(string filePath)
        {
            IWorkspaceFactory pWorkspaceFactory = new ShapefileWorkspaceFactory();
            IWorkspaceFactoryLockControl pWorkspaceFactoryLockControl = pWorkspaceFactory as IWorkspaceFactoryLockControl;
            if (pWorkspaceFactoryLockControl.SchemaLockingEnabled)
            {
                pWorkspaceFactoryLockControl.DisableSchemaLocking();
            }
            IWorkspace pWorkspace = pWorkspaceFactory.OpenFromFile(System.IO.Path.GetDirectoryName(filePath), 0);
            IFeatureWorkspace pFeatureWorkspace = pWorkspace as IFeatureWorkspace;
            IFeatureClass pFeatureClass = pFeatureWorkspace.OpenFeatureClass(System.IO.Path.GetFileName(filePath));
            return pFeatureClass;
        }
    }
}

程序运行结果如下：