用一个 latlon 点和到该点的距离值绘制一个椭圆

Question

我想围绕一个点画一个椭圆，为此我正在创建一个矩形并在其中绘制椭圆。

对于矩形，我需要点、宽度和高度。我有重点，但没有宽度和高度。我唯一拥有的就是与该点的距离。我想用那个距离计算矩形的宽度和高度？

从该点到它周围任意方向的距离为 2 公里。

Rectangle rec = new Rectangle(Convert.ToInt32(cx), Convert.ToInt32(cy), width, height);
gr.DrawEllipse(Pens.Red, rec);gr.FillEllipse(Brushes.Red, rec);

Answer 1

我就是这样做的，

private static ENCX.S57Draw _draw;

 Savedrfpt.Lat = Convert.ToDouble(24.34567);
 Savedrfpt.Lon = Convert.ToDouble(54.32456);
 ENCX.PixelPoint Saved_rfpixpts = _draw.GeoPix.Point(Savedrfpt);

double Distance_meters = Convert.ToDouble(2) * 1000;
double pixelpermeters = getPixelSizeInMeters();
Double d = Distance_meters / pixelpermeters;
gr.DrawEllipse(greenPen, (float)Saved_rfpixpts.X - (float)d, (float)Saved_rfpixpts.Y - (float)d, (float)d + (float)d, (float)d + (float)d);
gr.FillEllipse(brush, (float)Saved_rfpixpts.X - (float)d, (float)Saved_rfpixpts.Y - (float)d, (float)d + (float)d, (float)d + (float)d);


 public double getPixelSizeInMeters()
        {
            double sizem = _draw.PixelSizeMetres;
            double disscale = _draw.GeoPix.DisplayScale;
            return _draw.PixelSizeMetres * _draw.GeoPix.DisplayScale;
        }

谢谢，

用一个 latlon 点和到该点的距离值绘制一个椭圆

Draw an ellipse with one latlon point and a distance value from that point

c#

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rectangles

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