/// <summary>
/// 求图幅与区域交点
/// </summary>
/// <param name="edge">边代号</param>
/// <param name="p1">起点</param>
/// <param name="p2">终点</param>
/// <returns></returns>
public BPoint FindIntersection(int edge, BPoint p1, BPoint p2)
{
double B = 0, L = 0;
double minx, miny, maxx, maxy;
minx = mapSheet.WSPoint1.L;
maxx = mapSheet.ENPoint1.L;
miny = mapSheet.WSPoint1.B;
maxy = mapSheet.ENPoint1.B;
if (edge == 1)
{
L = minx;
B = p2.B + (p2.B - p1.B) * (minx - p2.L) / (p2.L - p1.L);
}
else if (edge == 3)
{
L = maxx;
B = p2.B + (p2.B - p1.B) * (maxx - p2.L) / (p2.L - p1.L);
}
else if (edge == 2)
{
B = miny;
L = p2.L + (miny - p2.B) * (p2.L - p1.L) / (p2.B - p1.B);
}
else if (edge == 4)
{
B = maxy;
L = p2.L + (maxy - p2.B) * (p2.L - p1.L) / (p2.B - p1.B);
}
return(new BPoint(B, L));
}
/// <summary>
/// 计算角点
/// </summary>
/// <param name="latDiffer"></param>
/// <param name="lonDiffer"></param>
public void CalculateSheetPoints(double latDiffer, double lonDiffer)
{
char[] alpha = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V' };
string row = sheetNum.Substring(0, 1);
int a = 0, b = 0, c = 0, d = 0;
for (int i = 0; i < 22; i++)
{
if (row.Equals(alpha[i].ToString()))
{
a = i + 1;
}
}
b = int.Parse(sheetNum.Substring(1, 2));
double latitude = (a - 1) * 4;
double longitude = (b - 31) * 6;
if (sheetNum.Length > 3)
{
c = int.Parse(sheetNum.Substring(4, 3));
d = int.Parse(sheetNum.Substring(7, 3));
latitude = (a - 1) * 4 + (4 / latDiffer - c) * latDiffer;
longitude = (b - 31) * 6 + (d - 1) * lonDiffer;
}
//计算西南角的经纬度坐标
//经纬度，单位：度
//转为弧度
latitude = latitude * Math.PI / 180;
longitude = longitude * Math.PI / 180;
latDiffer = latDiffer * Math.PI / 180;
lonDiffer = lonDiffer * Math.PI / 180;
WSPoint = new BPoint(latitude, longitude);
ENPoint = new BPoint(latitude + latDiffer, lonDiffer + longitude);
}
/// <summary>
/// 判断点是否在图幅内
/// </summary>
/// <param name="edge">边代号</param>
/// <param name="pt">某点</param>
/// <returns></returns>
public bool InSide(int edge, BPoint pt)
{
double latdiffer = 0, londiffer = 0;
Tool.SetLatAndLonDif(MainForm.MeaScale, ref latdiffer, ref londiffer);
mapSheet.CalculateSheetPoints(latdiffer, londiffer);
double minx, miny, maxx, maxy;
minx = mapSheet.WSPoint1.L;
maxx = mapSheet.ENPoint1.L;
miny = mapSheet.WSPoint1.B;
maxy = mapSheet.ENPoint1.B;
if (edge == 1 && pt.L < minx || edge == 3 && pt.L > maxx || edge == 2 && pt.B < miny || edge == 4 && pt.B > maxy)
{
return(false);
}
return(true);
}
