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Geo.js
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Geo.js
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/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
/* Geodesy representation conversion functions (c) Chris Veness 2002-2010 */
/* - www.movable-type.co.uk/scripts/latlong.html */
/* */
/* Sample usage: */
/* var lat = Geo.parseDMS('51° 28′ 40.12″ N'); */
/* var lon = Geo.parseDMS('000° 00′ 05.31″ W'); */
/* var p1 = new LatLon(lat, lon); */
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
var Geo = {}; // Geo namespace, representing static class
/**
* Parses string representing degrees/minutes/seconds into numeric degrees
*
* This is very flexible on formats, allowing signed decimal degrees, or deg-min-sec optionally
* suffixed by compass direction (NSEW). A variety of separators are accepted (eg 3º 37' 09"W)
* or fixed-width format without separators (eg 0033709W). Seconds and minutes may be omitted.
* (Note minimal validation is done).
*
* @param {String|Number} dmsStr: Degrees or deg/min/sec in variety of formats
* @returns {Number} Degrees as decimal number
* @throws {TypeError} dmsStr is an object, perhaps DOM object without .value?
*/
Geo.parseDMS = function(dmsStr) {
if (typeof deg == 'object') throw new TypeError('Geo.parseDMS - dmsStr is [DOM?] object');
// check for signed decimal degrees without NSEW, if so return it directly
if (typeof dmsStr === 'number' && isFinite(dmsStr)) return Number(dmsStr);
// strip off any sign or compass dir'n & split out separate d/m/s
var dms = String(dmsStr).trim().replace(/^-/,'').replace(/[NSEW]$/i,'').split(/[^0-9.,]+/);
if (dms[dms.length-1]=='') dms.splice(dms.length-1); // from trailing symbol
if (dms == '') return NaN;
// and convert to decimal degrees...
switch (dms.length) {
case 3: // interpret 3-part result as d/m/s
var deg = dms[0]/1 + dms[1]/60 + dms[2]/3600;
break;
case 2: // interpret 2-part result as d/m
var deg = dms[0]/1 + dms[1]/60;
break;
case 1: // just d (possibly decimal) or non-separated dddmmss
var deg = dms[0];
// check for fixed-width unseparated format eg 0033709W
if (/[NS]/i.test(dmsStr)) deg = '0' + deg; // - normalise N/S to 3-digit degrees
if (/[0-9]{7}/.test(deg)) deg = deg.slice(0,3)/1 + deg.slice(3,5)/60 + deg.slice(5)/3600;
break;
default:
return NaN;
}
if (/^-|[WS]$/i.test(dmsStr.trim())) deg = -deg; // take '-', west and south as -ve
return Number(deg);
}
/**
* Convert decimal degrees to deg/min/sec format
* - degree, prime, double-prime symbols are added, but sign is discarded, though no compass
* direction is added
*
* @private
* @param {Number} deg: Degrees
* @param {String} [format=dms]: Return value as 'd', 'dm', 'dms'
* @param {Number} [dp=0|2|4]: No of decimal places to use - default 0 for dms, 2 for dm, 4 for d
* @returns {String} deg formatted as deg/min/secs according to specified format
* @throws {TypeError} deg is an object, perhaps DOM object without .value?
*/
Geo.toDMS = function(deg, format, dp) {
if (typeof deg == 'object') throw new TypeError('Geo.toDMS - deg is [DOM?] object');
if (isNaN(deg)) return 'NaN'; // give up here if we can't make a number from deg
// default values
if (typeof format == 'undefined') format = 'dms';
if (typeof dp == 'undefined') {
switch (format) {
case 'd':dp = 4;break;
case 'dm':dp = 2;break;
case 'dms':dp = 0;break;
default:format = 'dms';dp = 0; // be forgiving on invalid format
}
}
deg = Math.abs(deg); // (unsigned result ready for appending compass dir'n)
switch (format) {
case 'd':
d = deg.toFixed(dp); // round degrees
if (d<100) d = '0' + d; // pad with leading zeros
if (d<10) d = '0' + d;
dms = d + '\u00B0'; // add º symbol
break;
case 'dm':
var min = (deg*60).toFixed(dp); // convert degrees to minutes & round
var d = Math.floor(min / 60); // get component deg/min
var m = (min % 60).toFixed(dp); // pad with trailing zeros
if (d<100) d = '0' + d; // pad with leading zeros
if (d<10) d = '0' + d;
if (m<10) m = '0' + m;
dms = d + '\u00B0' + m + '\u2032'; // add º, ' symbols
break;
case 'dms':
var sec = (deg*3600).toFixed(dp); // convert degrees to seconds & round
var d = Math.floor(sec / 3600); // get component deg/min/sec
var m = Math.floor(sec/60) % 60;
var s = (sec % 60).toFixed(dp); // pad with trailing zeros
if (d<100) d = '0' + d; // pad with leading zeros
if (d<10) d = '0' + d;
if (m<10) m = '0' + m;
if (s<10) s = '0' + s;
dms = d + '\u00B0' + m + '\u2032' + s + '\u2033'; // add º, ', " symbols
break;
}
return dms;
}
/**
* Convert numeric degrees to deg/min/sec latitude (suffixed with N/S)
*
* @param {Number} deg: Degrees
* @param {String} [format=dms]: Return value as 'd', 'dm', 'dms'
* @param {Number} [dp=0|2|4]: No of decimal places to use - default 0 for dms, 2 for dm, 4 for d
* @returns {String} Deg/min/seconds
*/
Geo.toLat = function(deg, format, dp) {
var lat = Geo.toDMS(deg, format, dp);
return lat=='' ? '' : lat.slice(1) + (deg<0 ? 'S' : 'N'); // knock off initial '0' for lat!
}
/**
* Convert numeric degrees to deg/min/sec longitude (suffixed with E/W)
*
* @param {Number} deg: Degrees
* @param {String} [format=dms]: Return value as 'd', 'dm', 'dms'
* @param {Number} [dp=0|2|4]: No of decimal places to use - default 0 for dms, 2 for dm, 4 for d
* @returns {String} Deg/min/seconds
*/
Geo.toLon = function(deg, format, dp) {
var lon = Geo.toDMS(deg, format, dp);
return lon=='' ? '' : lon + (deg<0 ? 'W' : 'E');
}
/**
* Convert numeric degrees to deg/min/sec as a bearing (0º..360º)
*
* @param {Number} deg: Degrees
* @param {String} [format=dms]: Return value as 'd', 'dm', 'dms'
* @param {Number} [dp=0|2|4]: No of decimal places to use - default 0 for dms, 2 for dm, 4 for d
* @returns {String} Deg/min/seconds
*/
Geo.toBrng = function(deg, format, dp) {
deg = (Number(deg)+360) % 360; // normalise -ve values to 180º..360º
var brng = Geo.toDMS(deg, format, dp);
return brng.replace('360', '0'); // just in case rounding took us up to 360º!
}
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
/* Vincenty Inverse Solution of Geodesics on the Ellipsoid (c) Chris Veness 2002-2010 */
/* */
/* from: Vincenty inverse formula - T Vincenty, "Direct and Inverse Solutions of Geodesics on the */
/* Ellipsoid with application of nested equations", Survey Review, vol XXII no 176, 1975 */
/* http://www.ngs.noaa.gov/PUBS_LIB/inverse.pdf */
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
/**
* Calculates geodetic distance between two points specified by latitude/longitude using
* Vincenty inverse formula for ellipsoids
*
* @param {Number} lat1, lon1: first point in decimal degrees
* @param {Number} lat2, lon2: second point in decimal degrees
* @returns {Number} distance in metres between points
*/
Geo.dist = function(lat1, lon1, lat2, lon2, fix) {
lat1 = Number(lat1), lon1 = Number(lon1), lat2 = Number(lat2), lon2 = Number(lon2);
var a = 6378137, b = 6356752.314245, f = 1/298.257223563; // WGS-84 ellipsoid params
var L = (lon2-lon1).toRad();
var U1 = Math.atan((1-f) * Math.tan(lat1.toRad()));
var U2 = Math.atan((1-f) * Math.tan(lat2.toRad()));
var sinU1 = Math.sin(U1), cosU1 = Math.cos(U1);
var sinU2 = Math.sin(U2), cosU2 = Math.cos(U2);
var lambda = L, lambdaP, iterLimit = 100;
do {
var sinLambda = Math.sin(lambda), cosLambda = Math.cos(lambda);
var sinSigma = Math.sqrt((cosU2*sinLambda) * (cosU2*sinLambda) +
(cosU1*sinU2-sinU1*cosU2*cosLambda) * (cosU1*sinU2-sinU1*cosU2*cosLambda));
if (sinSigma==0) return 0; // co-incident points
var cosSigma = sinU1*sinU2 + cosU1*cosU2*cosLambda;
var sigma = Math.atan2(sinSigma, cosSigma);
var sinAlpha = cosU1 * cosU2 * sinLambda / sinSigma;
var cosSqAlpha = 1 - sinAlpha*sinAlpha;
var cos2SigmaM = cosSigma - 2*sinU1*sinU2/cosSqAlpha;
if (isNaN(cos2SigmaM)) cos2SigmaM = 0; // equatorial line: cosSqAlpha=0 (§6)
var C = f/16*cosSqAlpha*(4+f*(4-3*cosSqAlpha));
lambdaP = lambda;
lambda = L + (1-C) * f * sinAlpha *
(sigma + C*sinSigma*(cos2SigmaM+C*cosSigma*(-1+2*cos2SigmaM*cos2SigmaM)));
} while (Math.abs(lambda-lambdaP) > 1e-12 && --iterLimit>0);
if (iterLimit==0) return NaN // formula failed to converge
var uSq = cosSqAlpha * (a*a - b*b) / (b*b);
var A = 1 + uSq/16384*(4096+uSq*(-768+uSq*(320-175*uSq)));
var B = uSq/1024 * (256+uSq*(-128+uSq*(74-47*uSq)));
var deltaSigma = B*sinSigma*(cos2SigmaM+B/4*(cosSigma*(-1+2*cos2SigmaM*cos2SigmaM)-
B/6*cos2SigmaM*(-3+4*sinSigma*sinSigma)*(-3+4*cos2SigmaM*cos2SigmaM)));
var s = b*A*(sigma-deltaSigma);
s = s.toFixed(fix === undefined ? 3 : fix); // round to 1mm precision
return s;
};
Geo.genMatrix = function(center, granularity, radius, callback) {
var matrix = [], multiple = parseInt(radius/granularity),
// reference point, lower-left corner of the matrix
refPoint = center.getSquarePoints(radius/Math.sin(45)/2).sw, hasCallback = typeof callback === 'function';
function gen(i, j) {
var bearing, hypotenuse;
if (i == j) {
if (i == 0) {
hasCallback ? callback(refPoint) : matrix.push(refPoint);
return;
}
bearing = 45;
}
if (j == 0) {
// on axis i
bearing = 0;
hypotenuse = i;
}
if (i == 0) {
// on axis j
bearing = 90;
hypotenuse = j;
}
hypotenuse = hypotenuse ? hypotenuse : Math.sqrt(Math.pow(i, 2) + Math.pow(j, 2));
bearing = (Math.asin(j/hypotenuse)).toDeg();
var dest = refPoint.destinationPoint(bearing, granularity*hypotenuse);
hasCallback ? callback(dest) : matrix.push(dest);
return;
}
// the matrix
// i is vertical axis, j is horizontal axis, angle's opposite is j
for (var i = 0; i <= multiple; i++) {
for (var j = 0; j <= multiple;j++) {
gen(i, j);
}
}
if (!hasCallback)
return matrix;
};
// CommonJS
try {
if (module && module.exports) {
module.exports = Geo;
}
} catch(e) {}