using System;

public static class LatLongConversionCalculator
{
    //the conversion variable to go from degrees to radians 
    private static readonly double RadConv = Math.PI / 180;
    //radius of the earth
    private static readonly double R = 6371e3;

    public static double PythagoreanDistanceFinder(double lat, double longi, double testableLat, double testableLong)
    {
        //convert to radians
        double φ1 = lat * RadConv;
        double φ2 = testableLat * RadConv;
        double λ1 = longi * RadConv;
        double λ2 = testableLong * RadConv;

        //Pythagorean projection formula 
        double x = (λ2 - λ1) * Math.Cos((φ1 + φ2) / 2);
        double y = (φ2 - φ1);
        float distance = (float) (Math.Sqrt(x * x + y * y) * R);

        return distance; 
    }

    public static double PythagoreanΔLatProjInverse(double latmeters, double lat)
    {
        //inverse of the latitude projection formula with a supplied meter value
        double φ1 = lat * RadConv;

        double y = latmeters / R;
        double radX = y + φ1;
        double DeltaX = (radX / RadConv) - lat;

        return DeltaX;
    }

    public static double PythagoreanΔLoniProjInverse(double longimeters, double lat, double longi)
    {
        //inverse of the longitude projection formula with a supplied meter value
        double φ1 = lat * RadConv;
        double λ1 = longi * RadConv;

        double x = longimeters / R;
        double radY = (x / Math.Cos((φ1 + φ1) * 0.5)) + λ1;
        double DeltaY = (radY / RadConv) - longi; 

        return DeltaY;
    }
}