非本人原创.
同事在网上找的
合并速度较快
/// <summary>
/// 计算合并面积(去掉岛)
/// </summary>
/// <param name="pArrayPolygon">图形集合</param>
/// <param name="isShowError"></param>
/// <returns></returns>
public static IPolygon UnionOrRemoveRingFromPolygon(ArrayList pArrayPolygon, bool isShowError)
{
IPolygon pPolygon_Each = null;
IPolygon pPolygon_Result = null;
IGeometryCollection pGeometryCollection = null;
ISegmentCollection pSegmentCollection_Ring = null;
object oMissing = Type.Missing;
try
{
if (pArrayPolygon == null)
return null;
if (pArrayPolygon.Count == 0)
return null;
pGeometryCollection = new PolygonClass();
pPolygon_Result = pGeometryCollection as IPolygon;
for (int i = 0; i < pArrayPolygon.Count; i++)
{
pPolygon_Each = pArrayPolygon[i] as IPolygon;
IGeometryCollection pGeometryCollection_Temp = null;
pGeometryCollection_Temp = pPolygon_Each as IGeometryCollection;
for (int j = 0; j < pGeometryCollection_Temp.GeometryCount; j++)
{
pSegmentCollection_Ring = new RingClass();
pSegmentCollection_Ring.AddSegmentCollection(pGeometryCollection_Temp.get_Geometry(j) as ISegmentCollection);
pGeometryCollection.AddGeometry(pSegmentCollection_Ring as IGeometry, ref oMissing, ref oMissing);
}
}
pPolygon_Result.SimplifyPreserveFromTo();
return pPolygon_Result;
}
catch (Exception ex)
{
//if (isShowError)
// MessageBox.Show("合并(去岛)多边形发生错误,错误信息为:->\r\n" + ex.Message,
// "错误信息", MessageBoxButtons.OK, MessageBoxIcon.Error);
return null;
}
}