在ArcGIS中叠加操作会带来碎图斑或狭长面，而这些碎图斑或狭长面又会影响后续的判断。所以就需要消除。
例如：
具体操作有以下方式：
1、最简单的的方法就是使用ArcGIS提供的“消除工具”。在"数据管理工具"——“制图综合”——“消除”。
2、使用Python脚本
# -*-coding:gbk-*-import arcpyfrom arcpy import envimport time# 融合指定条件的图斑try:source_gdb_path = "F:/GIS测试数据/测试.gdb" # 原始图层工作空间in_features = "POLYGON" # 输入图层expression = "SHAPE_AREA <50 or SHAPE_Area/ SHAPE_Length<0.2" # 融合限制条件env.workspace = source_gdb_pathtime_begin = time.time()print "消除指定条件下的要素{0}".format(expression)tempLayer = "block_layer"# SearchCursorfcount = len([feature[0] for feature in arcpy.da.SearchCursor(in_features, "SHAPE_AREA", expression)])while (fcount > 0):print('fcount:{0} Time : {1} s'.format(fcount, time.time() - time_begin))tempLayer = "{0}_b".format(tempLayer)# MakeFeatureLayerarcpy.MakeFeatureLayer_management(in_features, tempLayer)in_features = "{0}_E".format(in_features)if arcpy.Exists(in_features):arcpy.Delete_management(in_features)# SelectLayerByAttribute to define feature to be eliminatedarcpy.SelectLayerByAttribute_management(tempLayer, "NEW_SELECTION", expression)# Eliminatearcpy.Eliminate_management(tempLayer, in_features, "AREA")fcount2 = len([feature[0] for feature in arcpy.da.SearchCursor(in_features, "SHAPE_AREA", expression)])if fcount2 == fcount:breakelse:fcount = fcount2print "Total Time {0}".format(time.time() - time_begin)except Exception, e:print e.message.decode("utf_8")
3、AE+C#实现
/// <summary>/// 消除碎图斑/// </summary>/// <param name="pFeatureClass">要素类</param>/// <param name="whereClause">消除条件："SHAPE_AREA <50 or SHAPE_AREA/SHAPE_Length<0.2"</param>public static void Eliminate(IFeatureClass pFeatureClass, string whereClause){Dictionary<int, IGeometry> dicOidsGeo = new Dictionary<int, IGeometry>();ISpatialFilter pSpatialFilter = new SpatialFilterClass { WhereClause = whereClause, SubFields = $"SHAPE,{pFeatureClass.OIDFieldName}" };IFeatureCursor pFeatureCursor = pFeatureClass.Search(pSpatialFilter, true);IFeature pFeature = null;while ((pFeature = pFeatureCursor.NextFeature()) != null){(pFeature.ShapeCopy as ITopologicalOperator).Simplify();dicOidsGeo[pFeature.OID] = pFeature.ShapeCopy;}System.Runtime.InteropServices.Marshal.ReleaseComObject(pFeatureCursor);int count = dicOidsGeo.Count;while (count > 0){Console.WriteLine($"个数：{count}，时间：{DateTime.Now}");int count2 = ExcudeEliminate(dicOidsGeo, pFeatureClass);if (count2 == count)break;elsecount = count2;}}/// <summary>/// 消除碎图斑，融到相邻面积最大面/// </summary>/// <param name="dicOidsGeo">几何集合</param>/// <param name="pFeatureClass">源要素类</param>/// <returns>未消除的个数</returns>public static int ExcudeEliminate(Dictionary<int, IGeometry> dicOidsGeo, IFeatureClass pFeatureClass){Func<IFeature, IGeometry, IGeometry> func = (pFeature1, ge) =>{ITopologicalOperator pTopolo = pFeature1.ShapeCopy as ITopologicalOperator;IGeometry geo = pTopolo.Union(ge);(geo as ITopologicalOperator).Simplify();return geo;};List<int> lisOids = new List<int>(); //记录已经融合的要素IDIFeatureCursor pFeatureCursor = null;IFeature pFeature = null;ISpatialFilter pSpatialFilter = new SpatialFilterClass { SpatialRel = esriSpatialRelEnum.esriSpatialRelIntersects, GeometryField = pFeatureClass.ShapeFieldName, PostfixClause = "Order by SHAPE_AREA desc" };foreach (var ge in dicOidsGeo){pSpatialFilter.Geometry = ge.Value;pFeatureCursor = pFeatureClass.Update(pSpatialFilter, false);pFeature = pFeatureCursor.NextFeature();if (pFeature != null){pFeature.Shape = func(pFeature, ge.Value);pFeatureCursor.UpdateFeature(pFeature);lisOids.Add(ge.Key);}}System.Runtime.InteropServices.Marshal.ReleaseComObject(pFeatureCursor);if (lisOids.Count == 0)return dicOidsGeo.Count;var str = string.Empty;//删除lisOids.ForEach(x =>{str += $",{x}";dicOidsGeo.Remove(x);});str = str.Substring(1);IQueryFilter pQueryFilter = new QueryFilterClass();pQueryFilter.WhereClause = $"{pFeatureClass.OIDFieldName} in ({str})"; //str超过1000时需要分组pFeatureCursor = pFeatureClass.Update(pQueryFilter, false);while((pFeature= pFeatureCursor.NextFeature())!= null){pFeatureCursor.DeleteFeature();}System.Runtime.InteropServices.Marshal.ReleaseComObject(pFeatureCursor);return dicOidsGeo.Count;}
