public class XYandLatLong
        {
            static float zeroX = 5000000f;
            static float zeroZ = 6600000f;
            // data for recalculation

            static float centerX = 11465000f - zeroX; // circle center
            static float centerZ = 6500000f - zeroZ;

            static float pnSxW_X = 4468608.57f - zeroX; // point 40dgN : 24dgE
            static float pnSxW_Z = 5730893.72f - zeroZ;

            static float pnNxW_X = 5357858.31f - zeroX; // point 48dgN : 24dgE
            static float pnNxW_Z = 5828649.53f - zeroZ;

            static float pnSxE_X = 4468608.57f - zeroX; // point 40dgN : 42dgE
            static float pnSxE_Z = 7269106.20f - zeroZ;

            static float pnNxE_X = 5357858.31f - zeroX; // point 48dgN : 42dgE
            static float pnNxE_Z = 7171350.00f - zeroZ;

            //
            static double lenNorth = Math.Sqrt((pnNxW_X - centerX) * (pnNxW_X - centerX) + (pnNxW_Z - centerZ) * (pnNxW_Z - centerZ));
            static double lenSouth = Math.Sqrt((pnSxW_X - centerX) * (pnSxW_X - centerX) + (pnSxW_Z - centerZ) * (pnSxW_Z - centerZ));
            static double lenN_S = lenSouth - lenNorth;

            static double RealAngleMaxLongitude = Math.Atan(((double)pnSxW_Z - centerZ) / (pnSxW_X - centerX)) * 180f / Math.PI;
            // borders
            static float EndWest = 24f;
            static float EndEast = 42f;
            static float EndNorth = 48f;
            static float EndSouth = 40f;
            static float MiddleLongitude = (EndWest + EndEast) / 2;
            static float ToLengthN_S = (float)((EndNorth - EndSouth) / lenN_S);
            static double ToAngleW_E = (MiddleLongitude - EndWest) / RealAngleMaxLongitude;

            public static double Longitude(float x, float z)    // degrees , (x (meters) - to North, z (meters) - to East)
            {
                double ang = -Math.Atan(((double)(z - centerZ)) / (x - centerX)) * ToDegree;
                return ang * ToAngleW_E + MiddleLongitude;
            }

            public static double Latitude(float x, float z)    // degrees (x (meters) - to North, z (meters) - to East)
            {
                double len = lenSouth - Math.Sqrt((x-centerX)*(x-centerX) + (z-centerZ)*(z-centerZ));
                return len * ToLengthN_S + EndSouth;
            }

            public static PointCarte GetCoords(double inLatitudeDegrees, double inLongitudeDegrees)
            {
                // Lo coordinates system
                double realAng = (inLongitudeDegrees - MiddleLongitude) / ToAngleW_E / Utils.ToDegree;    
                double realLen = lenSouth - (inLatitudeDegrees - EndSouth) / ToLengthN_S;
                double outX = centerX - realLen * Math.Cos(realAng);
                double outZ = centerZ + realLen * Math.Sin(realAng);
                return new PointCarte(outX, outZ);
            }
        }