/// <summary>
/// 检查点是否在Polygon中
/// </summary>
/// <param name="p">点</param>
/// <param name="polygon">多边型</param>
/// <returns>在则返回true,否则返回false</returns>
public static bool PointInPolygon(Point p, Polygon polygon)
{
bool result = CheckPointOnPolygonLine(p, polygon);
if (result)
return true;
result = PointInTheMaxRectangle(p, polygon);
if (!result)
return false;
result = LineSegmentIntersectionInPolygonLine(p, polygon);
return result;
}
private bool InArea(decimal lat, decimal lon, out LocationInfo locationInfo)
{
locationInfo = null;
foreach (var item in ltPToL)
{
Polygon polygon = new Polygon(item.Points);
double x = Convert.ToDouble(lat);
double y = Convert.ToDouble(lon);
Point point = new Point(x, y);
bool isIn = Polygon.PointInPolygon(point, polygon);
if (isIn)
{
locationInfo = item.LocationInfo;
return true;
}
}
return false;
}
private static bool LineSegmentIntersectionInPolygonLine(Point p, Polygon polygon)
{
int intersectionCount = 0;
double maxX = GetMaxPointX(polygon.Points);
if (p.X > maxX)
{
maxX = p.X + 1;
}
else
{
maxX += 1;
}
LineSegment mainLine = new LineSegment(p, new Point(maxX, p.Y));
for (int i = 0, j = 1; j < polygon.Points.Count; i++, j++)
{
LineSegment line = new LineSegment(polygon.Points[i], polygon.Points[j]);
bool result = LineSegment.LineSegmentIntersection(mainLine, line);
if (result)
intersectionCount++;
}
LineSegment lastLine = new LineSegment(polygon.Points[polygon.Points.Count - 1], polygon.Points[0]);
bool lastResult = LineSegment.LineSegmentIntersection(mainLine, lastLine);
if (lastResult)
intersectionCount++;
if ((intersectionCount % 2) == 0)
return false;
return true;
}
public static bool PointInTheMaxRectangle(Point p, Polygon polygon)
{
double maxX = polygon.Points.Max(u => u.X);
double minX = polygon.Points.Min(u => u.X);
double maxY = polygon.Points.Max(u => u.Y);
double minY = polygon.Points.Min(u => u.Y);
LineSegment line = new LineSegment(new Point(maxX, maxY), new Point(minX, minY));
Rectangle rec = new Rectangle(line);
return Rectangle.PointInRectangle(p, rec);
}
private static bool CheckPointOnPolygonLine(Point p, Polygon polygon)
{
for (int i = 0, j = 1; j < polygon.Points.Count; i++, j++)
{
LineSegment line = new LineSegment(polygon.Points[i], polygon.Points[j]);
if (LineSegment.PointOnTheLine(p, line))
return true;
}
LineSegment lastLine = new LineSegment(polygon.Points[polygon.Points.Count - 1], polygon.Points[0]);
if (LineSegment.PointOnTheLine(p, lastLine))
return true;
return false;
}