Lat/Lon with buffer, C#

Lat/Lon with buffer

//Calculate a buffer for Lat/Lon bounds, so all points with a
//distance to the bounds are contained in these bounds.

using System;

namespace Rextester
{
    public class Program
    {
        public static void Main(string[] args)
        {
            // our latitude/longitude values for test
            var g1 = new Point(8, 49);
            var g2 = new Point(9, 50);

// 100 km
            double buffer = 100000;

// convert to Mercator (conformal)
            double x1, y1, x2, y2;
            var m1 = Wgs_2_SphereMercator(g1);
            var m2 = Wgs_2_SphereMercator(g2);

// The maxmimum absolute latitude will be used for ground resolution
            double maxLat = Math.Max(Math.Abs(g1.Y), Math.Abs(g2.Y));

// calculate the ground resoutlion for the latitude
            double groundResolution = Math.Cos(maxLat * Math.PI / 180.0);

// the ground resolution applied to the buffer
            var mercatorBuffer = buffer / groundResolution;

// now add the mercator buffer
            var mb1 = new Point(m1.X - mercatorBuffer, m1.Y - mercatorBuffer);
            var mb2 = new Point(m2.X + mercatorBuffer, m2.Y + mercatorBuffer);

// back to geo
            var gb1 = SphereMercator_2_Wgs(mb1);
            var gb2 = SphereMercator_2_Wgs(mb2);
            
            Console.WriteLine("Calculate a buffer for Lat/Lon bounds");
            Console.WriteLine("Bounds     : (lat: {1}, lon: {0}) / (lat: {3}, lon: {2})", g1.X, g1.Y, g2.X, g2.Y);
            Console.WriteLine("Buffer     : {0}m", buffer);
            Console.WriteLine("With Buffer: (lat: {1}, lon: {0}) / (lat: {3}, lon: {2})", gb1.X, gb1.Y, gb2.X, gb2.Y);

}

public static Point Wgs_2_SphereMercator(Point point, double earthRadius = 6371000)
        {
            double x = earthRadius * point.X * Math.PI / 180.0;
            double y = earthRadius * Math.Log(Math.Tan(Math.PI / 4.0 + point.Y * Math.PI / 360.0));

return new Point(x, y);
        }

public static Point SphereMercator_2_Wgs(Point point, double earthRadius = 6371000)
        {
            double x = (180.0/Math.PI)*(point.X/earthRadius);
            double y = (360/Math.PI)*(Math.Atan(Math.Exp(point.Y/earthRadius)) - (Math.PI/4));

return new Point(x, y);
        }
    }

public class Point
    {
        public Point(double x, double y)
        {
            this.X = x;
            this.Y = y;
        }

public double X { get; set; }
        public double Y { get; set; }
    }
}


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