/// <summary>
/// The validate method check if the XYPolyline is valid. The checks
/// made are:
/// - is number of points >= 3
/// - is the length of all line segments positiv
/// - do any lines cross
/// - is the area positiv
/// Exception is raised if the constraints are not met.
/// </summary>
public new void Validate()
{
if (Points.Count < 3)
{
throw new System.Exception("Number of vertices in polygon element is less than 3.");
}
if (GetArea() <= 0)
{
throw new System.Exception("Area of polygon is negative or zero. XYPolygons must be ordered counter clockwise.");
}
for (int j = 0; j < Points.Count; j++)
{
if (GetLine(j).GetLength() == 0)
{
throw new System.Exception("Length of line segment no: " +
j.ToString() + " (0-based) of XYPolygon is zero.");
}
}
for (int j = 0; j < Points.Count; j++)
{
for (int m = 0; m < j; m++)
{
if (XYGeometryTools.DoLineSegmentsIntersect(GetLine(j), GetLine(m)))
{
throw new System.Exception("Line no: " + j.ToString() + " and line no: " +
m.ToString() + " of XYPolygon crosses.");
}
}
}
}
/// <summary>
/// Returns true if the polygon is inside or on the edge of this polygon
/// </summary>
/// <param name="p"></param>
/// <returns></returns>
public bool Contains(IXYPolygon p)
{
IEnumerable <IXYPoint> points;
if (p is XYPolygon)
{
points = ((XYPolygon)p).Points;
}
else if (p is MultiPartPolygon)
{
points = ((MultiPartPolygon)p).Polygons.SelectMany(pp => pp.Points);
}
else
{
return(false);
}
//First check that all points are within the bounding box
foreach (var point in points)
{
if (!XYGeometryTools.IsPointInPolygonOrOnEdge(point.X, point.Y, BoundingBox))
{
return(false);
}
}
foreach (var point in points)
{
if (!XYGeometryTools.IsPointInPolygonOrOnEdge(point.X, point.Y, this))
{
return(false);
}
}
return(true);
}
public bool Contains(double X, double Y)
{
if (XYGeometryTools.IsPointInPolygon(X, Y, BoundingBox)) //Check the bounding box first
{
return(XYGeometryTools.IsPointInPolygon(X, Y, this));
}
else
{
return(false);
}
}
private bool OverLaps(XYPolygon Poly)
{
//Are any of the other polygon bounding box corners with in this polygon
if (Poly.BoundingBox.Points.Any(p => this.BoundingBox.Contains(p)))
{
foreach (var P in Poly.Points)
{
if (Contains(P))
{
return(true);
}
}
}
// Are any of this bounding box corners in the other polygon
if (this.BoundingBox.Points.Any(p => Poly.BoundingBox.Contains(p)))
{
foreach (var P in Points)
{
if (Poly.Contains(P))
{
return(true);
}
}
}
//Do any of the bounding box lines intersect/
for (int i = 0; i < 4; i++)
{
for (int j = 0; j < 4; j++)
{
if (XYGeometryTools.DoLineSegmentsIntersect(Poly.BoundingBox.Points[i], Poly.BoundingBox.Points[i + 1], BoundingBox.Points[j], BoundingBox.Points[j + 1]))
{
foreach (var P in Points)
{
if (Poly.Contains(P))
{
return(true);
}
}
foreach (var P in Poly.Points)
{
if (Contains(P))
{
return(true);
}
}
}
}
}
return(false);
}
/// <summary>
/// The method decides if the triangle formed by P(i-1), P(i) and
/// P(i+1) from Polygon are intersected by any of the other points
/// of the polygon.
/// </summary>
/// <param name="i">Middle index for the three points that forms the triangle</param>
/// <returns>
/// <p>true: If the triangle P(i-1), P(i), P(i+1) is intersected by other parts of Polygon</p>
/// <p>false: otherwise</p>
/// </returns>
protected bool IsIntersected(int i)
{
double x = 0;
double y = 0;
int n = Points.Count;
int im1 = i - 1;
int ip1 = i + 1;
if (i == 0)
{
im1 = n - 1;
}
else if (i == n - 1)
{
ip1 = 0;
}
XYPoint nodeim1 = new XYPoint((XYPoint)Points[im1]);
XYPoint nodei = new XYPoint((XYPoint)Points[i]);
XYPoint nodeip1 = new XYPoint((XYPoint)Points[ip1]);
XYPolygon localPolygon = new XYPolygon();
localPolygon.Points.Add(nodeim1);
localPolygon.Points.Add(nodei);
localPolygon.Points.Add(nodeip1);
int j = 0;
bool intersected = false;
while (((j < n - 1) && (!intersected)))
{
x = Points[j].X;
y = Points[j].Y;
if (((((j != im1) && (j != i)) && (j != ip1)) && XYGeometryTools.IsPointInPolygon(x, y, localPolygon)))
{
return(true);
}
else
{
j++;
}
}
return(false);
}
