//墨卡托投影反算程序
Point_new reverse_Mercator(Point_new point, double K, double e, double B)
{
Point_new new_Point;
double B_old = 0;
double B_new = 0;
double L0 = 0;
while (true)
{
B_new = PI / 2 - 2 * Math.Atan(Math.Exp(-point.y / K) * Math.Exp(e / 2 *
Math.Log((1 - e * Math.Sin(B_old)) / (1 + e * Math.Sin(B_old)))));
if (B_new - B_old < eps)
{
break;
}
B_old = B_new;
}
new_Point.x = (point.x / K + L0) * 180 / PI;
new_Point.y = B_new * 180 / PI;
return(new_Point);
}
//绘制江苏省地图
private void display_Click(object sender, EventArgs e)
{
int i = 0, j = 0;
bitmap = new Bitmap(width, height);
panel1.Refresh();
Graphics g = Graphics.FromImage(bitmap);
double scaleX, scaleY;
Pen my_pen = new Pen(Color.Blue, 1);
try
{
using (StreamReader sr = new StreamReader(fileName))
{
string str = sr.ReadLine();
while (str != "END")
{
List <Point_new> line = new List <Point_new>();
while ((str = sr.ReadLine()) != "END")
{
string[] split = str.Split(',');
line.Add(new Point_new(Convert.ToDouble(split[0]), Convert.ToDouble(split[1])));
}
Point_new[] line_new = new Point_new[line.Count];
for (i = 0; i < line.Count; ++i)
{
line_new[i] = line[i];
}
pointsArrayList.Add(line_new);
str = sr.ReadLine();
}
scaleX = (maxJSX - minJSX) / width;
scaleY = (maxJSY - minJSY) / height;
if (scaleX > scaleY)
{
for (i = 0; i < pointsArrayList.Count; i++)
{
Point[] MapPoints = new Point[pointsArrayList[i].Length];
for (j = 0; j < pointsArrayList[i].Length; j++)
{
MapPoints[j].X = (int)((pointsArrayList[i][j].x - minJSX) / scaleX);
MapPoints[j].Y = (int)((maxJSY - pointsArrayList[i][j].y) / scaleX);
}
g.DrawLines(my_pen, MapPoints);
}
}
else
{
for (i = 0; i < pointsArrayList.Count; i++)
{
Point[] MapPoints = new Point[pointsArrayList[i].Length];
for (j = 0; j < pointsArrayList[i].Length; j++)
{
MapPoints[j].X = (int)((pointsArrayList[i][j].x - minJSX) / scaleY);
MapPoints[j].Y = (int)((maxJSY - pointsArrayList[i][j].y) / scaleY);
}
g.DrawLines(my_pen, MapPoints);
}
}
panel1.BackgroundImage = bitmap;
panel1.Refresh();
}
}
catch (Exception ep11)
{
MessageBox.Show("The file cannot be read properly,because" + ep11.Message);
}
}
//求平面坐标系下的地市面积
private void button1_Click_1(object sender, EventArgs e)
{
richTextBox1.Clear();
area.Clear();
double temp = 0;
try
{
using (StreamReader sr = new StreamReader(fileName))
{
string str = sr.ReadLine();
while (str != "END")
{
List <Point_new> line = new List <Point_new>();
while ((str = sr.ReadLine()) != "END")
{
string[] split = str.Split(',');
line.Add(new Point_new(Convert.ToDouble(split[0]), Convert.ToDouble(split[1])));
}
Point_new[] line_new = new Point_new[line.Count];
for (int i = 0; i < line.Count; ++i)
{
line_new[i] = line[i];
}
pointsArrayList.Add(line_new);
str = sr.ReadLine();
}
for (int i = 0; i < pointsArrayList.Count; ++i)
{
if (i >= 1 && i <= 6)
{
for (int j = 1; j < pointsArrayList[i].Length; ++j)
{
if (j == pointsArrayList[i].Length - 1)
{
temp = temp + pointsArrayList[i][j].x * (pointsArrayList[i][1].y - pointsArrayList[i][j - 1].y) / 2;
}
else
{
temp = temp + pointsArrayList[i][j].x * (pointsArrayList[i][j + 1].y - pointsArrayList[i][j - 1].y) / 2;
}
}
if (i == 6)
{
area.Add(Math.Abs(temp));
}
}
else
{
for (int j = 1; j < pointsArrayList[i].Length; ++j)
{
if (j == pointsArrayList[i].Length - 1)
{
temp = temp + pointsArrayList[i][j].x * (pointsArrayList[i][1].y - pointsArrayList[i][j - 1].y) / 2;
}
else
{
temp = temp + pointsArrayList[i][j].x * (pointsArrayList[i][j + 1].y - pointsArrayList[i][j - 1].y) / 2;
}
}
area.Add(Math.Abs(temp));
}
temp = 0;
}
}
}
catch (Exception ep11)
{
MessageBox.Show("The file cannot be read properly,because" + ep11.Message);
}
for (int i = 0; i < 13; ++i)
{
richTextBox1.Text += "第" + (i + 1) + "块地市的面积为：" + Form1.area[i].ToString() + "m²" + Environment.NewLine;
}
}