using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

​

​

​

​

    //Port from javascript to c#

    //Javascript source: 

    //https://github.com/shahid28/utm-latlng/blob/master/UTMLatLng.js

    public class LatLngUTMConverter

    {

        public class LatLng

        {

            public double Lat { get; set; }

            public double Lng { get; set; }

        }

​

        public class UTMResult

        {

            public double Easting { get; set; }

            public double UTMEasting { get; set; }

            public double Northing { get; set; }

            public double UTMNorthing { get; set; }

            public int ZoneNumber { get; set; }

            public String ZoneLetter { get; set; }

            public String Zona

            {

                get

                {

                    return ZoneNumber + ZoneLetter;

                }

            }

​

            public override string ToString()

            {

                return "" + ZoneNumber + ZoneLetter + " " + Easting + "" + Northing;

            }

        }

​

        private double a;

        private double eccSquared;

        private bool status;

        private string datumName = "WGS 84";

​

        public LatLngUTMConverter(String datumNameIn)

        {

            if (!String.IsNullOrEmpty(datumNameIn))

            {

                datumName = datumNameIn;

            }

​

            this.setEllipsoid(datumName);

        }

​

        private double toRadians(double grad)

        {

            return grad * Math.PI / 180;

        }

​

        private String getUtmLetterDesignator(double latitude)

        {

            if ((84 >= latitude) && (latitude >= 72))

                return "X";

            else if ((72 > latitude) && (latitude >= 64))

                return "W";

            else if ((64 > latitude) && (latitude >= 56))

                return "V";

            else if ((56 > latitude) && (latitude >= 48))

                return "U";

            else if ((48 > latitude) && (latitude >= 40))

                return "T";

            else if ((40 > latitude) && (latitude >= 32))

                return "S";

            else if ((32 > latitude) && (latitude >= 24))

                return "R";

            else if ((24 > latitude) && (latitude >= 16))

                return "Q";

            else if ((16 > latitude) && (latitude >= 8))

                return "P";

            else if ((8 > latitude) && (latitude >= 0))

                return "N";

            else if ((0 > latitude) && (latitude >= -8))

                return "M";

            else if ((-8 > latitude) && (latitude >= -16))

                return "L";

            else if ((-16 > latitude) && (latitude >= -24))

                return "K";

            else if ((-24 > latitude) && (latitude >= -32))

                return "J";

            else if ((-32 > latitude) && (latitude >= -40))

                return "H";

            else if ((-40 > latitude) && (latitude >= -48))

                return "G";

            else if ((-48 > latitude) && (latitude >= -56))

                return "F";

            else if ((-56 > latitude) && (latitude >= -64))

                return "E";

            else if ((-64 > latitude) && (latitude >= -72))

                return "D";

            else if ((-72 > latitude) && (latitude >= -80))

                return "C";

            else

                return "Z";

        }

​

        public UTMResult convertLatLngToUtm(double latitude, double longitude)

        {

            if (status)

            {

                throw new Exception("No ecclipsoid data associated with unknown datum: " + datumName);

            }

​

            int ZoneNumber;

​

            var LongTemp = longitude;

            var LatRad = toRadians(latitude);

            var LongRad = toRadians(LongTemp);

​

            if (LongTemp >= 8 && LongTemp <= 13 && latitude > 54.5 && latitude < 58)

            {

                ZoneNumber = 32;

            }

            else if (latitude >= 56.0 && latitude < 64.0 && LongTemp >= 3.0 && LongTemp < 12.0)

            {

                ZoneNumber = 32;

            }

            else

            {

                ZoneNumber = (int) ((LongTemp + 180) / 6) + 1;

​

                if (latitude >= 72.0 && latitude < 84.0)

                {

                    if (LongTemp >= 0.0 && LongTemp < 9.0)

                    {

                        ZoneNumber = 31;

                    }

                    else if (LongTemp >= 9.0 && LongTemp < 21.0)

                    {

                        ZoneNumber = 33;

                    }

                    else if (LongTemp >= 21.0 && LongTemp < 33.0)

                    {

                        ZoneNumber = 35;

                    }

                    else if (LongTemp >= 33.0 && LongTemp < 42.0)

                    {

                        ZoneNumber = 37;

                    }

                }

            }

​

            var LongOrigin = (ZoneNumber - 1) * 6 - 180 + 3;  //+3 puts origin in middle of zone

            var LongOriginRad = toRadians(LongOrigin);

​

            var UTMZone = getUtmLetterDesignator(latitude);

​

            var eccPrimeSquared = (eccSquared) / (1 - eccSquared);

​

            var N = a / Math.Sqrt(1 - eccSquared * Math.Sin(LatRad) * Math.Sin(LatRad));

            var T = Math.Tan(LatRad) * Math.Tan(LatRad);

            var C = eccPrimeSquared * Math.Cos(LatRad) * Math.Cos(LatRad);

            var A = Math.Cos(LatRad) * (LongRad - LongOriginRad);

​

            var M = a * ((1 - eccSquared / 4 - 3 * eccSquared * eccSquared / 64 - 5 * eccSquared * eccSquared * eccSquared / 256) * LatRad

                    - (3 * eccSquared / 8 + 3 * eccSquared * eccSquared / 32 + 45 * eccSquared * eccSquared * eccSquared / 1024) * Math.Sin(2 * LatRad)

                    + (15 * eccSquared * eccSquared / 256 + 45 * eccSquared * eccSquared * eccSquared / 1024) * Math.Sin(4 * LatRad)

                    - (35 * eccSquared * eccSquared * eccSquared / 3072) * Math.Sin(6 * LatRad));

​

            var UTMEasting = 0.9996 * N * (A + (1 - T + C) * A * A * A / 6

                    + (5 - 18 * T + T * T + 72 * C - 58 * eccPrimeSquared) * A * A * A * A * A / 120)

                    + 500000.0;

​

            var UTMNorthing = 0.9996 * (M + N * Math.Tan(LatRad) * (A * A / 2 + (5 - T + 9 * C + 4 * C * C) * A * A * A * A / 24

                    + (61 - 58 * T + T * T + 600 * C - 330 * eccPrimeSquared) * A * A * A * A * A * A / 720));

​

            if (latitude < 0)

                UTMNorthing += 10000000.0;

​

            return new UTMResult { Easting= UTMEasting, Northing= UTMNorthing, ZoneNumber= ZoneNumber, ZoneLetter= UTMZone};

        }

​

        private void setEllipsoid(String name)

        {

            switch (name)

            {

                case "Airy":

                    a = 6377563;

                    eccSquared = 0.00667054;

                    break;

                case "Australian National":

                    a = 6378160;

                    eccSquared = 0.006694542;

                    break;

                case "Bessel 1841":

                    a = 6377397;

                    eccSquared = 0.006674372;

                    break;

                case "Bessel 1841 Nambia":

                    a = 6377484;

                    eccSquared = 0.006674372;

                    break;

                case "Clarke 1866":

                    a = 6378206;

                    eccSquared = 0.006768658;

                    break;

                case "Clarke 1880":

                    a = 6378249;

                    eccSquared = 0.006803511;

                    break;

                case "Everest":

                    a = 6377276;

                    eccSquared = 0.006637847;

                    break;

                case "Fischer 1960 Mercury":

                    a = 6378166;

                    eccSquared = 0.006693422;

                    break;

                case "Fischer 1968":

                    a = 6378150;

                    eccSquared = 0.006693422;

                    break;

                case "GRS 1967":

                    a = 6378160;

                    eccSquared = 0.006694605;

                    break;

                case "GRS 1980":

                    a = 6378137;

                    eccSquared = 0.00669438;

                    break;

                case "Helmert 1906":

                    a = 6378200;

                    eccSquared = 0.006693422;

                    break;

                case "Hough":

                    a = 6378270;

                    eccSquared = 0.00672267;

                    break;

                case "International":

                    a = 6378388;

                    eccSquared = 0.00672267;

                    break;

                case "Krassovsky":

                    a = 6378245;

                    eccSquared = 0.006693422;

                    break;

                case "Modified Airy":

                    a = 6377340;

                    eccSquared = 0.00667054;

                    break;

                case "Modified Everest":

                    a = 6377304;

                    eccSquared = 0.006637847;

                    break;

                case "Modified Fischer 1960":

                    a = 6378155;

                    eccSquared = 0.006693422;

                    break;

                case "South American 1969":

                    a = 6378160;

                    eccSquared = 0.006694542;

                    break;

                case "WGS 60":

                    a = 6378165;

                    eccSquared = 0.006693422;

                    break;

                case "WGS 66":

                    a = 6378145;

                    eccSquared = 0.006694542;

                    break;

                case "WGS 72":

                    a = 6378135;

                    eccSquared = 0.006694318;

                    break;

                case "ED50":

                    a = 6378388;

                    eccSquared = 0.00672267;

                    break; // International Ellipsoid

                case "WGS 84":

                case "EUREF89": // Max deviation from WGS 84 is 40 cm/km see http://ocq.dk/euref89 (in danish)

                case "ETRS89": // Same as EUREF89 

                    a = 6378137;

                    eccSquared = 0.00669438;

                    break;

                default:

                    status = true;

                    break;

            }

        }

​

        public LatLng convertUtmToLatLng(double UTMEasting, double UTMNorthing, int UTMZoneNumber, String UTMZoneLetter)

        {

            var e1 = (1 - Math.Sqrt(1 - this.eccSquared)) / (1 + Math.Sqrt(1 - this.eccSquared));

            var x = UTMEasting - 500000.0; //remove 500,000 meter offset for longitude

            var y = UTMNorthing;

            var ZoneNumber = UTMZoneNumber;

            var ZoneLetter = UTMZoneLetter;

            int NorthernHemisphere;

​

            if ("N" == ZoneLetter)

            {

                NorthernHemisphere = 1;

            }

            else

            {

                NorthernHemisphere = 0;

                y -= 10000000.0;

            }

​

            var LongOrigin = (ZoneNumber - 1) * 6 - 180 + 3;

​

            var eccPrimeSquared = (this.eccSquared) / (1 - this.eccSquared);

​

            double M = y / 0.9996;

            var mu = M / (this.a * (1 - this.eccSquared / 4 - 3 * this.eccSquared * this.eccSquared / 64 - 5 * this.eccSquared * this.eccSquared * this.eccSquared / 256));

​

            var phi1Rad = mu + (3 * e1 / 2 - 27 * e1 * e1 * e1 / 32) * Math.Sin(2 * mu)

                    + (21 * e1 * e1 / 16 - 55 * e1 * e1 * e1 * e1 / 32) * Math.Sin(4 * mu)

                    + (151 * e1 * e1 * e1 / 96) * Math.Sin(6 * mu);

            var phi1 = this.toDegrees(phi1Rad);

​

            var N1 = this.a / Math.Sqrt(1 - this.eccSquared * Math.Sin(phi1Rad) * Math.Sin(phi1Rad));

            var T1 = Math.Tan(phi1Rad) * Math.Tan(phi1Rad);

            var C1 = eccPrimeSquared * Math.Cos(phi1Rad) * Math.Cos(phi1Rad);

            var R1 = this.a * (1 - this.eccSquared) / Math.Pow(1 - this.eccSquared * Math.Sin(phi1Rad) * Math.Sin(phi1Rad), 1.5);

            var D = x / (N1 * 0.9996);

​

            var Lat = phi1Rad - (N1 * Math.Tan(phi1Rad) / R1) * (D * D / 2 - (5 + 3 * T1 + 10 * C1 - 4 * C1 * C1 - 9 * eccPrimeSquared) * D * D * D * D / 24

                    + (61 + 90 * T1 + 298 * C1 + 45 * T1 * T1 - 252 * eccPrimeSquared - 3 * C1 * C1) * D * D * D * D * D * D / 720);

            Lat = this.toDegrees(Lat);

​

            var Long = (D - (1 + 2 * T1 + C1) * D * D * D / 6 + (5 - 2 * C1 + 28 * T1 - 3 * C1 * C1 + 8 * eccPrimeSquared + 24 * T1 * T1)

                    * D * D * D * D * D / 120) / Math.Cos(phi1Rad);

            Long = LongOrigin + this.toDegrees(Long);

            return new LatLng { Lat = Lat, Lng = Long };

        }

​

        private double toDegrees (double rad) {

            return rad / Math.PI* 180;

        }

    }

​

​

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Test coordinate UTM 25833: 401051.31, 5813138.32 (Berlin OSW)");

        LatLngUTMConverter converter = new LatLngUTMConverter("ETRS89");

        //LatLngUTMConverter converter = new LatLngUTMConverter("");

        LatLngUTMConverter.LatLng latlng = converter.convertUtmToLatLng(401051.31, 5813138.32, 33, "N");

        Console.WriteLine("toLatLng: "+ latlng.Lat + " " + latlng.Lng);

        LatLngUTMConverter.UTMResult utm = converter.convertLatLngToUtm(latlng.Lat,latlng.Lng);

        Console.WriteLine("back to UTM: " + utm.Easting + " " + utm.Northing);

    }

}

​