獲取Polyline自相交點

• 背景：

       如果Polyline不為簡單的幾何圖形，則求出其自相交的點。如果FromPoint和ToPoint重合也一并返回。

• 實現邏輯：

       一、創建IMulitPoint pTargetPoint

       二、判斷Polyline是否首尾相接，如果首尾相接，將點加入到pTargetPoint;

       三、判斷Polyline是否為簡單的幾何圖形，如果不是則進行以下步驟：

            1）得出Polyline中所有Path的起點和終點，List<IPoint> lstOrigin;

            2）將Polyline簡單化，得出所有Path在LstOrigin中找不到的起點和終點，添加到pTargetPoint中

• 第三步的代碼：

private IMultipoint getInersectPoint(IPolyline pPolyline)
{
IGeometryCollection pGeoColl = pPolyline as IGeometryCollection;
List<IPoint> lstPoint = new List<IPoint>();
for (int i = 0; i < pGeoColl.GeometryCount; i++)
{
IPath pPath = pGeoColl.get_Geometry(i) as IPath;
IPoint pTemp = lstPoint.Find(p => (p.X == pPath.FromPoint.X && p.Y == pPath.FromPoint.Y));
if (pTemp == null) lstPoint.Add(pPath.FromPoint);
pTemp = lstPoint.Find(p => (p.X == pPath.ToPoint.X && p.Y == pPath.ToPoint.Y));
if (pTemp == null) lstPoint.Add(pPath.ToPoint);
}
ITopologicalOperator2 ptopo = pPolyline as ITopologicalOperator2;
ptopo.IsKnownSimple_2 = false;
ptopo.Simplify();
IMultipoint pMultipoint = new MultipointClass();
IPointCollection pPointColl = pMultipoint as IPointCollection;
for (int i = 0; i < pGeoColl.GeometryCount; i++)
{
IPath pPath = pGeoColl.get_Geometry(i) as IPath;
IPoint pTemp = lstPoint.Find(p => (p.X == pPath.FromPoint.X && p.Y == pPath.FromPoint.Y));
if (pTemp == null) pPointColl.AddPoint(pPath.FromPoint);
pTemp = lstPoint.Find(p => (p.X == pPath.ToPoint.X && p.Y == pPath.ToPoint.Y));
if (pTemp == null) pPointColl.AddPoint(pPath.ToPoint);
}
return pMultipoint;
}