ArcEngine合并要素

开发环境：VS2013 + ArcEngine 10.4
在数据量较大时，请用ITopologicalOperator的ConstructUnion方法，而不是一个一个Union

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Runtime.InteropServices;
using ESRI.ArcGIS.Carto;
using ESRI.ArcGIS.Controls;
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 WindowsFormsApplication2
{
    public class MergeTool
    {
        /// <summary>
        /// 输入要素
        /// </summary>
        private IFeatureClass in_FeatureClass;

        /// <summary>
        /// 构造函数
        /// </summary>
        /// <param name="in_FeatureClass"></param>
        public MergeTool(IFeatureClass in_FeatureClass)
        {
            this.in_FeatureClass = in_FeatureClass;
        }

        /// <summary>
        /// 获取空间参考
        /// </summary>
        /// <returns></returns>
        private ISpatialReference GetSpatialReference()
        {
            IGeoDataset pGeoDataset = in_FeatureClass as IGeoDataset;
            ISpatialReference pSpatialReference = pGeoDataset.SpatialReference;
            return pSpatialReference;
        }

        /// <summary>
        /// 合并几何体
        /// </summary>
        /// <returns></returns>
        private IGeometry GetMergeGeometry()
        {
            IGeometryBag pGeometryBag = new GeometryBag() as IGeometryBag;
            pGeometryBag.SpatialReference = GetSpatialReference();
            IGeometryCollection pGeometryCollection = pGeometryBag as IGeometryCollection;

            // 属性过滤
            IQueryFilter pQueryFilter = new QueryFilter();
            pQueryFilter.AddField("Shape");

            // 要素游标
            IFeatureCursor pFeatureCursor = in_FeatureClass.Search(pQueryFilter, true);
            IFeature pFeature = pFeatureCursor.NextFeature();
            if (pFeature == null)
            {
                return null;
            }

            // 遍历游标
            object missing = Type.Missing;
            while (pFeature != null)
            {
                pGeometryCollection.AddGeometry(pFeature.ShapeCopy, ref missing, ref missing);
                pFeature = pFeatureCursor.NextFeature();
            }
            Marshal.ReleaseComObject(pFeatureCursor);

            // 合并要素
            ITopologicalOperator pTopologicalOperator = null;
            if (in_FeatureClass.ShapeType == esriGeometryType.esriGeometryPoint)
            {
                pTopologicalOperator = new Multipoint() as ITopologicalOperator;
                pTopologicalOperator.ConstructUnion(pGeometryCollection as IEnumGeometry);
            }
            else if (in_FeatureClass.ShapeType == esriGeometryType.esriGeometryPolyline)
            {
                pTopologicalOperator = new Polyline() as ITopologicalOperator;
                pTopologicalOperator.ConstructUnion(pGeometryCollection as IEnumGeometry);
            }
            else
            {
                pTopologicalOperator = new Polygon() as ITopologicalOperator;
                pTopologicalOperator.ConstructUnion(pGeometryCollection as IEnumGeometry);
            }
            return pTopologicalOperator as IGeometry;
        }

        /// <summary>
        /// 执行工具
        /// </summary>
        /// <param name="filePath"></param>
        /// <returns></returns>
        public IFeatureClass ExecuteTool(string filePath)
        {
            IGeometryDef pGeometryDef = new GeometryDef();
            IGeometryDefEdit pGeometryDefEdit = pGeometryDef as IGeometryDefEdit;
            if (in_FeatureClass.ShapeType == esriGeometryType.esriGeometryPoint)
            {
                pGeometryDefEdit.GeometryType_2 = esriGeometryType.esriGeometryMultipoint;
                pGeometryDefEdit.HasM_2 = false;
                pGeometryDefEdit.HasZ_2 = false;
                pGeometryDefEdit.SpatialReference_2 = GetSpatialReference();
            }
            else if (in_FeatureClass.ShapeType == esriGeometryType.esriGeometryPolyline)
            {
                pGeometryDefEdit.GeometryType_2 = esriGeometryType.esriGeometryPolyline;
                pGeometryDefEdit.HasM_2 = false;
                pGeometryDefEdit.HasZ_2 = false;
                pGeometryDefEdit.SpatialReference_2 = GetSpatialReference();
            }
            else
            {
                pGeometryDefEdit.GeometryType_2 = esriGeometryType.esriGeometryPolygon;
                pGeometryDefEdit.HasM_2 = false;
                pGeometryDefEdit.HasZ_2 = false;
                pGeometryDefEdit.SpatialReference_2 = GetSpatialReference();
            }## 标题

            // 字段集合
            IFields pFields = new Fields();
            IFieldsEdit pFieldsEdit = pFields as IFieldsEdit;

            // Shape
            IField pField = new Field();
            IFieldEdit pFieldEdit = pField as IFieldEdit;
            pFieldEdit.Type_2 = esriFieldType.esriFieldTypeGeometry;
            pFieldEdit.GeometryDef_2 = pGeometryDef;
            pFieldEdit.AliasName_2 = "Shape";
            pFieldEdit.Name_2 = "Shape";
            pFieldEdit.IsNullable_2 = false;
            pFieldEdit.Required_2 = true;
            pFieldsEdit.AddField(pField);

            // 创建要素类
            IWorkspaceFactory pWorkspaceFactory = new ShapefileWorkspaceFactory();
            IWorkspace pWorkspace = pWorkspaceFactory.OpenFromFile(System.IO.Path.GetDirectoryName(filePath), 0);
            IFeatureWorkspace pFeatureWorkspace = pWorkspace as IFeatureWorkspace;
            IFeatureClass pFeatureClass = pFeatureWorkspace.CreateFeatureClass(System.IO.Path.GetFileName(filePath), pFields, null, null, esriFeatureType.esriFTSimple, "Shape", "");

            // 插入要素
            IFeatureBuffer pFeatureBuffer = pFeatureClass.CreateFeatureBuffer();
            IFeatureCursor pFeatureCursor = pFeatureClass.Insert(true);
            pFeatureBuffer.Shape = GetMergeGeometry();
            pFeatureCursor.InsertFeature(pFeatureBuffer);
            pFeatureCursor.Flush();
            return pFeatureClass;
        }
    }
}

运行结果：
初始数据如下图：

合并数据如下图：

转载自：https://blog.csdn.net/HerryDong/article/details/82751410