747 lines
20 KiB
JavaScript
747 lines
20 KiB
JavaScript
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/**
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* UTM zones are grouped, and assigned to one of a group of 6
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* sets.
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*
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* {int} @private
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*/
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var NUM_100K_SETS = 6;
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/**
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* The column letters (for easting) of the lower left value, per
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* set.
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*
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* {string} @private
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*/
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var SET_ORIGIN_COLUMN_LETTERS = 'AJSAJS';
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/**
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* The row letters (for northing) of the lower left value, per
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* set.
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*
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* {string} @private
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*/
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var SET_ORIGIN_ROW_LETTERS = 'AFAFAF';
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var A = 65; // A
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var I = 73; // I
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var O = 79; // O
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var V = 86; // V
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var Z = 90; // Z
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export default {
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forward: forward,
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inverse: inverse,
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toPoint: toPoint
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};
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/**
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* Conversion of lat/lon to MGRS.
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*
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* @param {object} ll Object literal with lat and lon properties on a
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* WGS84 ellipsoid.
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* @param {int} accuracy Accuracy in digits (5 for 1 m, 4 for 10 m, 3 for
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* 100 m, 2 for 1000 m or 1 for 10000 m). Optional, default is 5.
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* @return {string} the MGRS string for the given location and accuracy.
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*/
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export function forward(ll, accuracy) {
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accuracy = accuracy || 5; // default accuracy 1m
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return encode(LLtoUTM({
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lat: ll[1],
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lon: ll[0]
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}), accuracy);
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};
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/**
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* Conversion of MGRS to lat/lon.
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*
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* @param {string} mgrs MGRS string.
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* @return {array} An array with left (longitude), bottom (latitude), right
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* (longitude) and top (latitude) values in WGS84, representing the
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* bounding box for the provided MGRS reference.
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*/
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export function inverse(mgrs) {
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var bbox = UTMtoLL(decode(mgrs.toUpperCase()));
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if (bbox.lat && bbox.lon) {
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return [bbox.lon, bbox.lat, bbox.lon, bbox.lat];
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}
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return [bbox.left, bbox.bottom, bbox.right, bbox.top];
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};
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export function toPoint(mgrs) {
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var bbox = UTMtoLL(decode(mgrs.toUpperCase()));
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if (bbox.lat && bbox.lon) {
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return [bbox.lon, bbox.lat];
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}
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return [(bbox.left + bbox.right) / 2, (bbox.top + bbox.bottom) / 2];
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};
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/**
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* Conversion from degrees to radians.
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*
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* @private
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* @param {number} deg the angle in degrees.
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* @return {number} the angle in radians.
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*/
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function degToRad(deg) {
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return (deg * (Math.PI / 180.0));
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}
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/**
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* Conversion from radians to degrees.
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*
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* @private
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* @param {number} rad the angle in radians.
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* @return {number} the angle in degrees.
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*/
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function radToDeg(rad) {
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return (180.0 * (rad / Math.PI));
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}
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/**
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* Converts a set of Longitude and Latitude co-ordinates to UTM
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* using the WGS84 ellipsoid.
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*
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* @private
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* @param {object} ll Object literal with lat and lon properties
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* representing the WGS84 coordinate to be converted.
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* @return {object} Object literal containing the UTM value with easting,
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* northing, zoneNumber and zoneLetter properties, and an optional
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* accuracy property in digits. Returns null if the conversion failed.
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*/
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function LLtoUTM(ll) {
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var Lat = ll.lat;
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var Long = ll.lon;
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var a = 6378137.0; //ellip.radius;
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var eccSquared = 0.00669438; //ellip.eccsq;
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var k0 = 0.9996;
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var LongOrigin;
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var eccPrimeSquared;
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var N, T, C, A, M;
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var LatRad = degToRad(Lat);
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var LongRad = degToRad(Long);
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var LongOriginRad;
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var ZoneNumber;
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// (int)
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ZoneNumber = Math.floor((Long + 180) / 6) + 1;
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//Make sure the longitude 180.00 is in Zone 60
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if (Long === 180) {
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ZoneNumber = 60;
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}
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// Special zone for Norway
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if (Lat >= 56.0 && Lat < 64.0 && Long >= 3.0 && Long < 12.0) {
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ZoneNumber = 32;
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}
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// Special zones for Svalbard
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if (Lat >= 72.0 && Lat < 84.0) {
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if (Long >= 0.0 && Long < 9.0) {
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ZoneNumber = 31;
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}
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else if (Long >= 9.0 && Long < 21.0) {
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ZoneNumber = 33;
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}
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else if (Long >= 21.0 && Long < 33.0) {
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ZoneNumber = 35;
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}
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else if (Long >= 33.0 && Long < 42.0) {
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ZoneNumber = 37;
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}
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}
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LongOrigin = (ZoneNumber - 1) * 6 - 180 + 3; //+3 puts origin
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// in middle of
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// zone
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LongOriginRad = degToRad(LongOrigin);
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eccPrimeSquared = (eccSquared) / (1 - eccSquared);
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N = a / Math.sqrt(1 - eccSquared * Math.sin(LatRad) * Math.sin(LatRad));
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T = Math.tan(LatRad) * Math.tan(LatRad);
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C = eccPrimeSquared * Math.cos(LatRad) * Math.cos(LatRad);
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A = Math.cos(LatRad) * (LongRad - LongOriginRad);
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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));
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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);
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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)));
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if (Lat < 0.0) {
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UTMNorthing += 10000000.0; //10000000 meter offset for
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// southern hemisphere
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}
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return {
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northing: Math.round(UTMNorthing),
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easting: Math.round(UTMEasting),
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zoneNumber: ZoneNumber,
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zoneLetter: getLetterDesignator(Lat)
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};
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}
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/**
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* Converts UTM coords to lat/long, using the WGS84 ellipsoid. This is a convenience
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* class where the Zone can be specified as a single string eg."60N" which
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* is then broken down into the ZoneNumber and ZoneLetter.
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*
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* @private
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* @param {object} utm An object literal with northing, easting, zoneNumber
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* and zoneLetter properties. If an optional accuracy property is
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* provided (in meters), a bounding box will be returned instead of
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* latitude and longitude.
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* @return {object} An object literal containing either lat and lon values
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* (if no accuracy was provided), or top, right, bottom and left values
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* for the bounding box calculated according to the provided accuracy.
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* Returns null if the conversion failed.
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*/
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function UTMtoLL(utm) {
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var UTMNorthing = utm.northing;
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var UTMEasting = utm.easting;
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var zoneLetter = utm.zoneLetter;
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var zoneNumber = utm.zoneNumber;
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// check the ZoneNummber is valid
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if (zoneNumber < 0 || zoneNumber > 60) {
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return null;
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}
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var k0 = 0.9996;
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var a = 6378137.0; //ellip.radius;
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var eccSquared = 0.00669438; //ellip.eccsq;
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var eccPrimeSquared;
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var e1 = (1 - Math.sqrt(1 - eccSquared)) / (1 + Math.sqrt(1 - eccSquared));
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var N1, T1, C1, R1, D, M;
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var LongOrigin;
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var mu, phi1Rad;
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// remove 500,000 meter offset for longitude
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var x = UTMEasting - 500000.0;
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var y = UTMNorthing;
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// We must know somehow if we are in the Northern or Southern
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// hemisphere, this is the only time we use the letter So even
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// if the Zone letter isn't exactly correct it should indicate
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// the hemisphere correctly
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if (zoneLetter < 'N') {
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y -= 10000000.0; // remove 10,000,000 meter offset used
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// for southern hemisphere
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}
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// There are 60 zones with zone 1 being at West -180 to -174
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LongOrigin = (zoneNumber - 1) * 6 - 180 + 3; // +3 puts origin
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// in middle of
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// zone
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eccPrimeSquared = (eccSquared) / (1 - eccSquared);
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M = y / k0;
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mu = M / (a * (1 - eccSquared / 4 - 3 * eccSquared * eccSquared / 64 - 5 * eccSquared * eccSquared * eccSquared / 256));
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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);
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// double phi1 = ProjMath.radToDeg(phi1Rad);
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N1 = a / Math.sqrt(1 - eccSquared * Math.sin(phi1Rad) * Math.sin(phi1Rad));
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T1 = Math.tan(phi1Rad) * Math.tan(phi1Rad);
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C1 = eccPrimeSquared * Math.cos(phi1Rad) * Math.cos(phi1Rad);
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R1 = a * (1 - eccSquared) / Math.pow(1 - eccSquared * Math.sin(phi1Rad) * Math.sin(phi1Rad), 1.5);
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D = x / (N1 * k0);
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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);
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lat = radToDeg(lat);
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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);
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lon = LongOrigin + radToDeg(lon);
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var result;
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if (utm.accuracy) {
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var topRight = UTMtoLL({
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northing: utm.northing + utm.accuracy,
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easting: utm.easting + utm.accuracy,
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zoneLetter: utm.zoneLetter,
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zoneNumber: utm.zoneNumber
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});
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result = {
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top: topRight.lat,
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right: topRight.lon,
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bottom: lat,
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left: lon
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};
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}
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else {
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result = {
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lat: lat,
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lon: lon
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};
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}
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return result;
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}
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/**
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* Calculates the MGRS letter designator for the given latitude.
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*
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* @private
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* @param {number} lat The latitude in WGS84 to get the letter designator
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* for.
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* @return {char} The letter designator.
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*/
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function getLetterDesignator(lat) {
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//This is here as an error flag to show that the Latitude is
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//outside MGRS limits
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var LetterDesignator = 'Z';
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if ((84 >= lat) && (lat >= 72)) {
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LetterDesignator = 'X';
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}
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else if ((72 > lat) && (lat >= 64)) {
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LetterDesignator = 'W';
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}
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else if ((64 > lat) && (lat >= 56)) {
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LetterDesignator = 'V';
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}
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else if ((56 > lat) && (lat >= 48)) {
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LetterDesignator = 'U';
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}
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else if ((48 > lat) && (lat >= 40)) {
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LetterDesignator = 'T';
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}
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else if ((40 > lat) && (lat >= 32)) {
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LetterDesignator = 'S';
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}
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else if ((32 > lat) && (lat >= 24)) {
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LetterDesignator = 'R';
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}
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else if ((24 > lat) && (lat >= 16)) {
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LetterDesignator = 'Q';
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}
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else if ((16 > lat) && (lat >= 8)) {
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LetterDesignator = 'P';
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}
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else if ((8 > lat) && (lat >= 0)) {
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LetterDesignator = 'N';
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}
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else if ((0 > lat) && (lat >= -8)) {
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LetterDesignator = 'M';
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}
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else if ((-8 > lat) && (lat >= -16)) {
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LetterDesignator = 'L';
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}
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else if ((-16 > lat) && (lat >= -24)) {
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LetterDesignator = 'K';
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}
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else if ((-24 > lat) && (lat >= -32)) {
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LetterDesignator = 'J';
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}
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else if ((-32 > lat) && (lat >= -40)) {
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LetterDesignator = 'H';
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}
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else if ((-40 > lat) && (lat >= -48)) {
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LetterDesignator = 'G';
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}
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else if ((-48 > lat) && (lat >= -56)) {
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LetterDesignator = 'F';
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}
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else if ((-56 > lat) && (lat >= -64)) {
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LetterDesignator = 'E';
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}
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else if ((-64 > lat) && (lat >= -72)) {
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LetterDesignator = 'D';
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}
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else if ((-72 > lat) && (lat >= -80)) {
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LetterDesignator = 'C';
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}
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return LetterDesignator;
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}
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/**
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* Encodes a UTM location as MGRS string.
|
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*
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* @private
|
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* @param {object} utm An object literal with easting, northing,
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* zoneLetter, zoneNumber
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* @param {number} accuracy Accuracy in digits (1-5).
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* @return {string} MGRS string for the given UTM location.
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*/
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function encode(utm, accuracy) {
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// prepend with leading zeroes
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var seasting = "00000" + utm.easting,
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snorthing = "00000" + utm.northing;
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return utm.zoneNumber + utm.zoneLetter + get100kID(utm.easting, utm.northing, utm.zoneNumber) + seasting.substr(seasting.length - 5, accuracy) + snorthing.substr(snorthing.length - 5, accuracy);
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}
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|
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/**
|
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* Get the two letter 100k designator for a given UTM easting,
|
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* northing and zone number value.
|
||
*
|
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* @private
|
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* @param {number} easting
|
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* @param {number} northing
|
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* @param {number} zoneNumber
|
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* @return the two letter 100k designator for the given UTM location.
|
||
*/
|
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function get100kID(easting, northing, zoneNumber) {
|
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var setParm = get100kSetForZone(zoneNumber);
|
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var setColumn = Math.floor(easting / 100000);
|
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var setRow = Math.floor(northing / 100000) % 20;
|
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return getLetter100kID(setColumn, setRow, setParm);
|
||
}
|
||
|
||
/**
|
||
* Given a UTM zone number, figure out the MGRS 100K set it is in.
|
||
*
|
||
* @private
|
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* @param {number} i An UTM zone number.
|
||
* @return {number} the 100k set the UTM zone is in.
|
||
*/
|
||
function get100kSetForZone(i) {
|
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var setParm = i % NUM_100K_SETS;
|
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if (setParm === 0) {
|
||
setParm = NUM_100K_SETS;
|
||
}
|
||
|
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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);
|
||
|
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// colInt and rowInt are the letters to build to return
|
||
var colInt = colOrigin + column - 1;
|
||
var rowInt = rowOrigin + row;
|
||
var rollover = false;
|
||
|
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if (colInt > Z) {
|
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colInt = colInt - Z + A - 1;
|
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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++;
|
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|
||
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);
|
||
}
|
||
|
||
}
|