/// <summary>
/// 获取外包矩形
/// </summary>
/// <returns></returns>
public moRectangle GetEnvelope()
{
moRectangle sRect = null;
if (_ShapeType == moGeometryTypeConstant.Point)
{
moPoint sPoint = (moPoint)_Geometry;
sRect = new moRectangle(sPoint.X, sPoint.X, sPoint.Y, sPoint.Y);
}
else if (_ShapeType == moGeometryTypeConstant.MultiPolyline)
{
moMultiPolyline sMultiPolyline = (moMultiPolyline)_Geometry;
sRect = sMultiPolyline.GetEnvelope();
}
else
{
moMultiPolygon sMultiPolygon = (moMultiPolygon)_Geometry;
sRect = sMultiPolygon.GetEnvelope();
}
return(sRect);
}
/// <summary>
/// 指示指定点是否位于指定复合多边形内
/// </summary>
/// <param name="point"></param>
/// <param name="multiPolygon"></param>
/// <returns></returns>
public static bool IsPointWithinMultiPolygon(moPoint point, moMultiPolygon multiPolygon)
{
//（1）判断点是否位于外包矩形内，如否则返回否
moRectangle sExtent = multiPolygon.GetEnvelope();
if (IsPointWithinBox(point, sExtent) == false)
{
return(false);
}
//（2）射线法求交点个数
Int32 sIntersectionCount = 0; //交点个数
Int32 sPartCount = multiPolygon.Parts.Count;
for (Int32 i = 0; i <= sPartCount - 1; i++)
{
sIntersectionCount = sIntersectionCount + GetIntersectionCountBetweenRayAndPolygon(point, multiPolygon.Parts.GetItem(i));
}
if (sIntersectionCount % 2 == 1)
{
//奇数个，位于多边形内
return(true);
}
return(false);
}
/// <summary>
/// 指示指定复合多边形是否部分或完全位于指定矩形盒内
/// </summary>
/// <param name="multipolygon"></param>
/// <param name="box"></param>
/// <returns></returns>
public static bool IsMultiPolygonPartiallyWithinBox(moMultiPolygon multipolygon, moRectangle box)
{
//思路：先判断矩形盒是否相交，如是，按如下顺序，满足任何一个条件，则返回True
//（1）复合多边形任何一个点位于矩形盒内;
//（2）矩形盒任何一个顶点位于复合多边形内
//（3）矩形盒与复合多边形有交点
moRectangle sBox = multipolygon.GetEnvelope();
if (AreBoxesCross(sBox, box) == false)
{
return(false);
}
//（1）多边形任何一个点位于矩形盒内
Int32 sPartCount = multipolygon.Parts.Count;
for (Int32 i = 0; i <= sPartCount - 1; i++)
{
Int32 sPointCount = multipolygon.Parts.GetItem(i).Count;
for (Int32 j = 0; j <= sPointCount - 1; j++)
{
moPoint sCurPoint = multipolygon.Parts.GetItem(i).GetItem(j);
if (IsPointWithinBox(sCurPoint, box) == true)
{
return(true);
}
}
}
//（2）矩形盒任何一个顶点位于多边形内
moPoint sRectPoint = new moPoint(box.MinX, box.MinY); //左下点
if (IsPointWithinMultiPolygon(sRectPoint, multipolygon) == true)
{
return(true);
}
sRectPoint = new moPoint(box.MinX, box.MaxY); //左上点
if (IsPointWithinMultiPolygon(sRectPoint, multipolygon) == true)
{
return(true);
}
sRectPoint = new moPoint(box.MaxX, box.MaxY); //右上点
if (IsPointWithinMultiPolygon(sRectPoint, multipolygon) == true)
{
return(true);
}
sRectPoint = new moPoint(box.MaxX, box.MinY); //右下点
if (IsPointWithinMultiPolygon(sRectPoint, multipolygon) == true)
{
return(true);
}
//（3）矩形盒与复合多边形有交点
for (Int32 i = 0; i <= sPartCount - 1; i++)
{
moPoints sPoints = multipolygon.Parts.GetItem(i);
Int32 sPointCount = sPoints.Count;
for (Int32 j = 0; j <= sPointCount - 2; j++)
{
if (IsSegmentCrossBox(sPoints.GetItem(j), sPoints.GetItem(j + 1), box) == true)
{
return(true);
}
}
if (IsSegmentCrossBox(sPoints.GetItem(sPointCount - 1), sPoints.GetItem(0), box) == true)
{
return(true);
}
}
//（4）都不满足，返回false
return(false);
}