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Cesium-Examples/libs/iclient8c/examples/js/proj4js/lib/util/MGRS.js

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refactor: 求个star
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/*
Portions of this software are based on a port of components from the OpenMap
com.bbn.openmap.proj.coords Java package. An initial port was initially created
by Patrice G. Cappelaere and included in Community Mapbuilder
(http://svn.codehaus.org/mapbuilder/), which is licensed under the LGPL license
as per http://www.gnu.org/copyleft/lesser.html. OpenMap is licensed under the
following license agreement:
OpenMap Software License Agreement
----------------------------------
This Agreement sets forth the terms and conditions under which
the software known as OpenMap(tm) will be licensed by BBN
Technologies ("BBN") to you ("Licensee"), and by which Derivative
Works (as hereafter defined) of OpenMap will be licensed by you to BBN.
Definitions:
"Derivative Work(s)" shall mean any revision, enhancement,
modification, translation, abridgement, condensation or
expansion created by Licensee or BBN that is based upon the
Software or a portion thereof that would be a copyright
infringement if prepared without the authorization of the
copyright owners of the Software or portion thereof.
"OpenMap" shall mean a programmer's toolkit for building map
based applications as originally created by BBN, and any
Derivative Works thereof as created by either BBN or Licensee,
but shall include only those Derivative Works BBN has approved
for inclusion into, and BBN has integrated into OpenMap.
"Standard Version" shall mean OpenMap, as originally created by
BBN.
"Software" shall mean OpenMap and the Derivative Works created
by Licensee and the collection of files distributed by the
Licensee with OpenMap, and the collection of files created
through textual modifications.
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copyrights for the Derivative Works.
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of this Software. You may charge any fee you choose for support
of this Software. You may not charge a fee for this Software
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9. Each party hereto represents and warrants that they have the
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10. THIS PACKAGE IS PROVIDED "AS IS" WITHOUT WARRANTIES OF ANY
KIND, WHETHER EXPRESS OR IMPLIED, INCLUDING (BUT NOT LIMITED TO)
ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, AND
WITHOUT ANY WARRANTIES AS TO NONINFRINGEMENT.
11. IN NO EVENT SHALL COPYRIGHT HOLDER BE LIABLE FOR ANY DIRECT,
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United States complies, relating to the export or re-export of
any commodities, software, or technical data.
*/
if (window.Proj4js && !Proj4js.util) { Proj4js.util = {}; }
/**
* Converts between lat/lon and MGRS coordinates. Note that this static class
* is restricted to the WGS84 ellipsoid and does not support MGRS notations
* for polar regions (i.e. above 84° North and below 80° South).
*
* If Proj4js is loaded, this will be referenced as Proj4js.util.MGRS. If used
* standalone, it will be referenced as window.MGRS.
*
* @static
*/
(window.Proj4js ? Proj4js.util : window)["MGRS"] = (function() {
/**
* 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
/**
* 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, 4 for 1000 m or 5 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.lat, lon: ll.lon}), 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()));
return [bbox.left, bbox.bottom, bbox.right, bbox.top];
}
/**
* 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 == 'S') {
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) {
var seasting = "" + utm.easting,
snorthing = "" + 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 == null || 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;
if (sep > 0) {
var accuracyBonus = 100000.0 / Math.pow(10, sep);
var sepEastingString = mgrsString.substring(i, i + sep);
sepEasting = parseFloat(sepEastingString) * accuracyBonus;
var 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);
}
}
return {
forward: forward,
inverse: inverse
};
})();
if (window.Proj4js && Proj4js.Point) {
/**
* Creates a Proj4js.Point instance from a MGRS reference. The point will
* reference the center of the MGRS reference, and coordinates will be in
* WGS84 longitude and latitude.
*
* Only available if Proj4js is loaded.
*
* @param mgrs {string} MGRS reference
*/
Proj4js.Point.fromMGRS = function(mgrs) {
var llbbox = Proj4js.util.MGRS.inverse(mgrs);
return new Proj4js.Point(
(llbbox[2] + llbbox[0]) / 2,
(llbbox[3] + llbbox[1]) / 2
);
};
/**
* Converts a Proj4js.Point instance to a MGRS reference. The point
* coordinates are expected to be in WGS84 longitude and latitude.
*
* Only available if Proj4js is loaded.
*
* @param accuracy {int} The accuracy for the MGRS reference in digits (5
* for 1 m, 4 for 10 m, 3 for 100 m, 4 for 1000 m or 5 for 10000 m)
*/
Proj4js.Point.prototype.toMGRS = function(accuracy) {
return Proj4js.util.MGRS.forward({lon: this.x, lat: this.y}, accuracy);
};
}
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