(function (global, factory) { typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports) : typeof define === 'function' && define.amd ? define(['exports'], factory) : (factory((global.mgrs = global.mgrs || {}))); }(this, (function (exports) { 'use strict'; /** * UTM zones are grouped, and assigned to one of a group of 6 * sets. * * {int} @private */ var NUM_100K_SETS = 6; /** * The column letters (for easting) of the lower left value, per * set. * * {string} @private */ var SET_ORIGIN_COLUMN_LETTERS = 'AJSAJS'; /** * The row letters (for northing) of the lower left value, per * set. * * {string} @private */ var SET_ORIGIN_ROW_LETTERS = 'AFAFAF'; var A = 65; // A var I = 73; // I var O = 79; // O var V = 86; // V var Z = 90; // Z var mgrs = { forward: forward, inverse: inverse, toPoint: toPoint }; /** * Conversion of lat/lon to MGRS. * * @param {object} ll Object literal with lat and lon properties on a * WGS84 ellipsoid. * @param {int} accuracy Accuracy in digits (5 for 1 m, 4 for 10 m, 3 for * 100 m, 2 for 1000 m or 1 for 10000 m). Optional, default is 5. * @return {string} the MGRS string for the given location and accuracy. */ function forward(ll, accuracy) { accuracy = accuracy || 5; // default accuracy 1m return encode(LLtoUTM({ lat: ll[1], lon: ll[0] }), accuracy); } /** * Conversion of MGRS to lat/lon. * * @param {string} mgrs MGRS string. * @return {array} An array with left (longitude), bottom (latitude), right * (longitude) and top (latitude) values in WGS84, representing the * bounding box for the provided MGRS reference. */ function inverse(mgrs) { var bbox = UTMtoLL(decode(mgrs.toUpperCase())); if (bbox.lat && bbox.lon) { return [bbox.lon, bbox.lat, bbox.lon, bbox.lat]; } return [bbox.left, bbox.bottom, bbox.right, bbox.top]; } function toPoint(mgrs) { var bbox = UTMtoLL(decode(mgrs.toUpperCase())); if (bbox.lat && bbox.lon) { return [bbox.lon, bbox.lat]; } return [(bbox.left + bbox.right) / 2, (bbox.top + bbox.bottom) / 2]; } /** * Conversion from degrees to radians. * * @private * @param {number} deg the angle in degrees. * @return {number} the angle in radians. */ function degToRad(deg) { return (deg * (Math.PI / 180.0)); } /** * Conversion from radians to degrees. * * @private * @param {number} rad the angle in radians. * @return {number} the angle in degrees. */ function radToDeg(rad) { return (180.0 * (rad / Math.PI)); } /** * Converts a set of Longitude and Latitude co-ordinates to UTM * using the WGS84 ellipsoid. * * @private * @param {object} ll Object literal with lat and lon properties * representing the WGS84 coordinate to be converted. * @return {object} Object literal containing the UTM value with easting, * northing, zoneNumber and zoneLetter properties, and an optional * accuracy property in digits. Returns null if the conversion failed. */ function LLtoUTM(ll) { var Lat = ll.lat; var Long = ll.lon; var a = 6378137.0; //ellip.radius; var eccSquared = 0.00669438; //ellip.eccsq; var k0 = 0.9996; var LongOrigin; var eccPrimeSquared; var N, T, C, A, M; var LatRad = degToRad(Lat); var LongRad = degToRad(Long); var LongOriginRad; var ZoneNumber; // (int) ZoneNumber = Math.floor((Long + 180) / 6) + 1; //Make sure the longitude 180.00 is in Zone 60 if (Long === 180) { ZoneNumber = 60; } // Special zone for Norway if (Lat >= 56.0 && Lat < 64.0 && Long >= 3.0 && Long < 12.0) { ZoneNumber = 32; } // Special zones for Svalbard if (Lat >= 72.0 && Lat < 84.0) { if (Long >= 0.0 && Long < 9.0) { ZoneNumber = 31; } else if (Long >= 9.0 && Long < 21.0) { ZoneNumber = 33; } else if (Long >= 21.0 && Long < 33.0) { ZoneNumber = 35; } else if (Long >= 33.0 && Long < 42.0) { ZoneNumber = 37; } } LongOrigin = (ZoneNumber - 1) * 6 - 180 + 3; //+3 puts origin // in middle of // zone LongOriginRad = degToRad(LongOrigin); eccPrimeSquared = (eccSquared) / (1 - eccSquared); N = a / Math.sqrt(1 - eccSquared * Math.sin(LatRad) * Math.sin(LatRad)); T = Math.tan(LatRad) * Math.tan(LatRad); C = eccPrimeSquared * Math.cos(LatRad) * Math.cos(LatRad); A = Math.cos(LatRad) * (LongRad - LongOriginRad); 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 = (k0 * N * (A + (1 - T + C) * A * A * A / 6.0 + (5 - 18 * T + T * T + 72 * C - 58 * eccPrimeSquared) * A * A * A * A * A / 120.0) + 500000.0); var UTMNorthing = (k0 * (M + N * Math.tan(LatRad) * (A * A / 2 + (5 - T + 9 * C + 4 * C * C) * A * A * A * A / 24.0 + (61 - 58 * T + T * T + 600 * C - 330 * eccPrimeSquared) * A * A * A * A * A * A / 720.0))); if (Lat < 0.0) { UTMNorthing += 10000000.0; //10000000 meter offset for // southern hemisphere } return { northing: Math.round(UTMNorthing), easting: Math.round(UTMEasting), zoneNumber: ZoneNumber, zoneLetter: getLetterDesignator(Lat) }; } /** * Converts UTM coords to lat/long, using the WGS84 ellipsoid. This is a convenience * class where the Zone can be specified as a single string eg."60N" which * is then broken down into the ZoneNumber and ZoneLetter. * * @private * @param {object} utm An object literal with northing, easting, zoneNumber * and zoneLetter properties. If an optional accuracy property is * provided (in meters), a bounding box will be returned instead of * latitude and longitude. * @return {object} An object literal containing either lat and lon values * (if no accuracy was provided), or top, right, bottom and left values * for the bounding box calculated according to the provided accuracy. * Returns null if the conversion failed. */ function UTMtoLL(utm) { var UTMNorthing = utm.northing; var UTMEasting = utm.easting; var zoneLetter = utm.zoneLetter; var zoneNumber = utm.zoneNumber; // check the ZoneNummber is valid if (zoneNumber < 0 || zoneNumber > 60) { return null; } var k0 = 0.9996; var a = 6378137.0; //ellip.radius; var eccSquared = 0.00669438; //ellip.eccsq; var eccPrimeSquared; var e1 = (1 - Math.sqrt(1 - eccSquared)) / (1 + Math.sqrt(1 - eccSquared)); var N1, T1, C1, R1, D, M; var LongOrigin; var mu, phi1Rad; // remove 500,000 meter offset for longitude var x = UTMEasting - 500000.0; var y = UTMNorthing; // We must know somehow if we are in the Northern or Southern // hemisphere, this is the only time we use the letter So even // if the Zone letter isn't exactly correct it should indicate // the hemisphere correctly if (zoneLetter < 'N') { y -= 10000000.0; // remove 10,000,000 meter offset used // for southern hemisphere } // There are 60 zones with zone 1 being at West -180 to -174 LongOrigin = (zoneNumber - 1) * 6 - 180 + 3; // +3 puts origin // in middle of // zone eccPrimeSquared = (eccSquared) / (1 - eccSquared); M = y / k0; mu = M / (a * (1 - eccSquared / 4 - 3 * eccSquared * eccSquared / 64 - 5 * eccSquared * eccSquared * eccSquared / 256)); 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); // double phi1 = ProjMath.radToDeg(phi1Rad); N1 = a / Math.sqrt(1 - eccSquared * Math.sin(phi1Rad) * Math.sin(phi1Rad)); T1 = Math.tan(phi1Rad) * Math.tan(phi1Rad); C1 = eccPrimeSquared * Math.cos(phi1Rad) * Math.cos(phi1Rad); R1 = a * (1 - eccSquared) / Math.pow(1 - eccSquared * Math.sin(phi1Rad) * Math.sin(phi1Rad), 1.5); D = x / (N1 * k0); 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 = radToDeg(lat); var lon = (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); lon = LongOrigin + radToDeg(lon); var result; if (utm.accuracy) { var topRight = UTMtoLL({ northing: utm.northing + utm.accuracy, easting: utm.easting + utm.accuracy, zoneLetter: utm.zoneLetter, zoneNumber: utm.zoneNumber }); result = { top: topRight.lat, right: topRight.lon, bottom: lat, left: lon }; } else { result = { lat: lat, lon: lon }; } return result; } /** * Calculates the MGRS letter designator for the given latitude. * * @private * @param {number} lat The latitude in WGS84 to get the letter designator * for. * @return {char} The letter designator. */ function getLetterDesignator(lat) { //This is here as an error flag to show that the Latitude is //outside MGRS limits var LetterDesignator = 'Z'; if ((84 >= lat) && (lat >= 72)) { LetterDesignator = 'X'; } else if ((72 > lat) && (lat >= 64)) { LetterDesignator = 'W'; } else if ((64 > lat) && (lat >= 56)) { LetterDesignator = 'V'; } else if ((56 > lat) && (lat >= 48)) { LetterDesignator = 'U'; } else if ((48 > lat) && (lat >= 40)) { LetterDesignator = 'T'; } else if ((40 > lat) && (lat >= 32)) { LetterDesignator = 'S'; } else if ((32 > lat) && (lat >= 24)) { LetterDesignator = 'R'; } else if ((24 > lat) && (lat >= 16)) { LetterDesignator = 'Q'; } else if ((16 > lat) && (lat >= 8)) { LetterDesignator = 'P'; } else if ((8 > lat) && (lat >= 0)) { LetterDesignator = 'N'; } else if ((0 > lat) && (lat >= -8)) { LetterDesignator = 'M'; } else if ((-8 > lat) && (lat >= -16)) { LetterDesignator = 'L'; } else if ((-16 > lat) && (lat >= -24)) { LetterDesignator = 'K'; } else if ((-24 > lat) && (lat >= -32)) { LetterDesignator = 'J'; } else if ((-32 > lat) && (lat >= -40)) { LetterDesignator = 'H'; } else if ((-40 > lat) && (lat >= -48)) { LetterDesignator = 'G'; } else if ((-48 > lat) && (lat >= -56)) { LetterDesignator = 'F'; } else if ((-56 > lat) && (lat >= -64)) { LetterDesignator = 'E'; } else if ((-64 > lat) && (lat >= -72)) { LetterDesignator = 'D'; } else if ((-72 > lat) && (lat >= -80)) { LetterDesignator = 'C'; } return LetterDesignator; } /** * Encodes a UTM location as MGRS string. * * @private * @param {object} utm An object literal with easting, northing, * zoneLetter, zoneNumber * @param {number} accuracy Accuracy in digits (1-5). * @return {string} MGRS string for the given UTM location. */ function encode(utm, accuracy) { // prepend with leading zeroes var seasting = "00000" + utm.easting, snorthing = "00000" + utm.northing; return utm.zoneNumber + utm.zoneLetter + get100kID(utm.easting, utm.northing, utm.zoneNumber) + seasting.substr(seasting.length - 5, accuracy) + snorthing.substr(snorthing.length - 5, accuracy); } /** * Get the two letter 100k designator for a given UTM easting, * northing and zone number value. * * @private * @param {number} easting * @param {number} northing * @param {number} zoneNumber * @return the two letter 100k designator for the given UTM location. */ function get100kID(easting, northing, zoneNumber) { var setParm = get100kSetForZone(zoneNumber); var setColumn = Math.floor(easting / 100000); var setRow = Math.floor(northing / 100000) % 20; return getLetter100kID(setColumn, setRow, setParm); } /** * Given a UTM zone number, figure out the MGRS 100K set it is in. * * @private * @param {number} i An UTM zone number. * @return {number} the 100k set the UTM zone is in. */ function get100kSetForZone(i) { var setParm = i % NUM_100K_SETS; if (setParm === 0) { setParm = NUM_100K_SETS; } return setParm; } /** * Get the two-letter MGRS 100k designator given information * translated from the UTM northing, easting and zone number. * * @private * @param {number} column the column index as it relates to the MGRS * 100k set spreadsheet, created from the UTM easting. * Values are 1-8. * @param {number} row the row index as it relates to the MGRS 100k set * spreadsheet, created from the UTM northing value. Values * are from 0-19. * @param {number} parm the set block, as it relates to the MGRS 100k set * spreadsheet, created from the UTM zone. Values are from * 1-60. * @return two letter MGRS 100k code. */ function getLetter100kID(column, row, parm) { // colOrigin and rowOrigin are the letters at the origin of the set var index = parm - 1; var colOrigin = SET_ORIGIN_COLUMN_LETTERS.charCodeAt(index); var rowOrigin = SET_ORIGIN_ROW_LETTERS.charCodeAt(index); // colInt and rowInt are the letters to build to return var colInt = colOrigin + column - 1; var rowInt = rowOrigin + row; var rollover = false; if (colInt > Z) { colInt = colInt - Z + A - 1; rollover = true; } if (colInt === I || (colOrigin < I && colInt > I) || ((colInt > I || colOrigin < I) && rollover)) { colInt++; } if (colInt === O || (colOrigin < O && colInt > O) || ((colInt > O || colOrigin < O) && rollover)) { colInt++; if (colInt === I) { colInt++; } } if (colInt > Z) { colInt = colInt - Z + A - 1; } if (rowInt > V) { rowInt = rowInt - V + A - 1; rollover = true; } else { rollover = false; } if (((rowInt === I) || ((rowOrigin < I) && (rowInt > I))) || (((rowInt > I) || (rowOrigin < I)) && rollover)) { rowInt++; } if (((rowInt === O) || ((rowOrigin < O) && (rowInt > O))) || (((rowInt > O) || (rowOrigin < O)) && rollover)) { rowInt++; if (rowInt === I) { rowInt++; } } if (rowInt > V) { rowInt = rowInt - V + A - 1; } var twoLetter = String.fromCharCode(colInt) + String.fromCharCode(rowInt); return twoLetter; } /** * Decode the UTM parameters from a MGRS string. * * @private * @param {string} mgrsString an UPPERCASE coordinate string is expected. * @return {object} An object literal with easting, northing, zoneLetter, * zoneNumber and accuracy (in meters) properties. */ function decode(mgrsString) { if (mgrsString && mgrsString.length === 0) { throw ("MGRSPoint coverting from nothing"); } var length = mgrsString.length; var hunK = null; var sb = ""; var testChar; var i = 0; // get Zone number while (!(/[A-Z]/).test(testChar = mgrsString.charAt(i))) { if (i >= 2) { throw ("MGRSPoint bad conversion from: " + mgrsString); } sb += testChar; i++; } var zoneNumber = parseInt(sb, 10); if (i === 0 || i + 3 > length) { // A good MGRS string has to be 4-5 digits long, // ##AAA/#AAA at least. throw ("MGRSPoint bad conversion from: " + mgrsString); } var zoneLetter = mgrsString.charAt(i++); // Should we check the zone letter here? Why not. if (zoneLetter <= 'A' || zoneLetter === 'B' || zoneLetter === 'Y' || zoneLetter >= 'Z' || zoneLetter === 'I' || zoneLetter === 'O') { throw ("MGRSPoint zone letter " + zoneLetter + " not handled: " + mgrsString); } hunK = mgrsString.substring(i, i += 2); var set = get100kSetForZone(zoneNumber); var east100k = getEastingFromChar(hunK.charAt(0), set); var north100k = getNorthingFromChar(hunK.charAt(1), set); // We have a bug where the northing may be 2000000 too low. // How // do we know when to roll over? while (north100k < getMinNorthing(zoneLetter)) { north100k += 2000000; } // calculate the char index for easting/northing separator var remainder = length - i; if (remainder % 2 !== 0) { throw ("MGRSPoint has to have an even number \nof digits after the zone letter and two 100km letters - front \nhalf for easting meters, second half for \nnorthing meters" + mgrsString); } var sep = remainder / 2; var sepEasting = 0.0; var sepNorthing = 0.0; var accuracyBonus, sepEastingString, sepNorthingString, easting, northing; if (sep > 0) { accuracyBonus = 100000.0 / Math.pow(10, sep); sepEastingString = mgrsString.substring(i, i + sep); sepEasting = parseFloat(sepEastingString) * accuracyBonus; sepNorthingString = mgrsString.substring(i + sep); sepNorthing = parseFloat(sepNorthingString) * accuracyBonus; } easting = sepEasting + east100k; northing = sepNorthing + north100k; return { easting: easting, northing: northing, zoneLetter: zoneLetter, zoneNumber: zoneNumber, accuracy: accuracyBonus }; } /** * Given the first letter from a two-letter MGRS 100k zone, and given the * MGRS table set for the zone number, figure out the easting value that * should be added to the other, secondary easting value. * * @private * @param {char} e The first letter from a two-letter MGRS 100´k zone. * @param {number} set The MGRS table set for the zone number. * @return {number} The easting value for the given letter and set. */ function getEastingFromChar(e, set) { // colOrigin is the letter at the origin of the set for the // column var curCol = SET_ORIGIN_COLUMN_LETTERS.charCodeAt(set - 1); var eastingValue = 100000.0; var rewindMarker = false; while (curCol !== e.charCodeAt(0)) { curCol++; if (curCol === I) { curCol++; } if (curCol === O) { curCol++; } if (curCol > Z) { if (rewindMarker) { throw ("Bad character: " + e); } curCol = A; rewindMarker = true; } eastingValue += 100000.0; } return eastingValue; } /** * Given the second letter from a two-letter MGRS 100k zone, and given the * MGRS table set for the zone number, figure out the northing value that * should be added to the other, secondary northing value. You have to * remember that Northings are determined from the equator, and the vertical * cycle of letters mean a 2000000 additional northing meters. This happens * approx. every 18 degrees of latitude. This method does *NOT* count any * additional northings. You have to figure out how many 2000000 meters need * to be added for the zone letter of the MGRS coordinate. * * @private * @param {char} n Second letter of the MGRS 100k zone * @param {number} set The MGRS table set number, which is dependent on the * UTM zone number. * @return {number} The northing value for the given letter and set. */ function getNorthingFromChar(n, set) { if (n > 'V') { throw ("MGRSPoint given invalid Northing " + n); } // rowOrigin is the letter at the origin of the set for the // column var curRow = SET_ORIGIN_ROW_LETTERS.charCodeAt(set - 1); var northingValue = 0.0; var rewindMarker = false; while (curRow !== n.charCodeAt(0)) { curRow++; if (curRow === I) { curRow++; } if (curRow === O) { curRow++; } // fixing a bug making whole application hang in this loop // when 'n' is a wrong character if (curRow > V) { if (rewindMarker) { // making sure that this loop ends throw ("Bad character: " + n); } curRow = A; rewindMarker = true; } northingValue += 100000.0; } return northingValue; } /** * The function getMinNorthing returns the minimum northing value of a MGRS * zone. * * Ported from Geotrans' c Lattitude_Band_Value structure table. * * @private * @param {char} zoneLetter The MGRS zone to get the min northing for. * @return {number} */ function getMinNorthing(zoneLetter) { var northing; switch (zoneLetter) { case 'C': northing = 1100000.0; break; case 'D': northing = 2000000.0; break; case 'E': northing = 2800000.0; break; case 'F': northing = 3700000.0; break; case 'G': northing = 4600000.0; break; case 'H': northing = 5500000.0; break; case 'J': northing = 6400000.0; break; case 'K': northing = 7300000.0; break; case 'L': northing = 8200000.0; break; case 'M': northing = 9100000.0; break; case 'N': northing = 0.0; break; case 'P': northing = 800000.0; break; case 'Q': northing = 1700000.0; break; case 'R': northing = 2600000.0; break; case 'S': northing = 3500000.0; break; case 'T': northing = 4400000.0; break; case 'U': northing = 5300000.0; break; case 'V': northing = 6200000.0; break; case 'W': northing = 7000000.0; break; case 'X': northing = 7900000.0; break; default: northing = -1.0; } if (northing >= 0.0) { return northing; } else { throw ("Invalid zone letter: " + zoneLetter); } } exports['default'] = mgrs; exports.forward = forward; exports.inverse = inverse; exports.toPoint = toPoint; Object.defineProperty(exports, '__esModule', { value: true }); })));