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GPXSee/src/map/lambertazimuthal.cpp
2018-05-17 22:41:56 +02:00

71 lines
2.2 KiB
C++

#include <cmath>
#include "ellipsoid.h"
#include "lambertazimuthal.h"
#define sin2(x) (sin(x) * sin(x))
#define sqr(x) ((x) * (x))
LambertAzimuthal::LambertAzimuthal(const Ellipsoid *ellipsoid,
double latitudeOrigin, double longitudeOrigin, double falseEasting,
double falseNorthing)
{
double lat0 = deg2rad(latitudeOrigin);
_falseEasting = falseEasting;
_falseNorthing = falseNorthing;
_lon0 = deg2rad(longitudeOrigin);
_a = ellipsoid->radius();
_es = ellipsoid->es();
_e = sqrt(_es);
double q0 = (1.0 - _es) * ((sin(lat0) / (1.0 - _es * sin2(lat0)))
- ((1.0/(2.0*_e)) * log((1.0 - _e * sin(lat0)) / (1.0 + _e
* sin(lat0)))));
_qP = (1.0 - _es) * ((1.0 / (1.0 - _es)) - ((1.0/(2.0*_e))
* log((1.0 - _e) / (1.0 + _e))));
_beta0 = asin(q0 / _qP);
_Rq = _a * sqrt(_qP / 2.0);
_D = _a * (cos(lat0) / sqrt(1.0 - _es * sin2(lat0))) / (_Rq * cos(_beta0));
}
PointD LambertAzimuthal::ll2xy(const Coordinates &c) const
{
double lon = deg2rad(c.lon());
double lat = deg2rad(c.lat());
double q = (1.0 - _es) * ((sin(lat) / (1.0 - _es * sin2(lat)))
- ((1.0/(2.0*_e)) * log((1.0 - _e * sin(lat)) / (1.0 + _e
* sin(lat)))));
double beta = asin(q / _qP);
double B = _Rq * sqrt(2.0 / (1.0 + sin(_beta0) * sin(beta) + (cos(_beta0)
* cos(beta) * cos(lon - _lon0))));
double x = _falseEasting + ((B * _D) * (cos(beta) * sin(lon - _lon0)));
double y = _falseNorthing + (B / _D) * ((cos(_beta0) * sin(beta))
- (sin(_beta0) * cos(beta) * cos(lon - _lon0)));
return PointD(x, y);
}
Coordinates LambertAzimuthal::xy2ll(const PointD &p) const
{
double es4 = _es * _es;
double es6 = _es * es4;
double rho = sqrt(sqr((p.x() - _falseEasting) / _D) + sqr(_D * (p.y()
- _falseNorthing)));
double C = 2.0 * asin(rho / (2.0*_Rq));
double betaS = asin((cos(C) * sin(_beta0)) + ((_D * (p.y() -_falseNorthing)
* sin(C) * cos(_beta0)) / rho));
double lon = _lon0 + atan((p.x() - _falseEasting) * sin(C) / (_D * rho
* cos(_beta0) * cos(C) - sqr(_D) * (p.y() - _falseNorthing) * sin(_beta0)
* sin(C)));
double lat = betaS + ((_es/3.0 + 31.0*es4/180.0 + 517.0*es6/5040.0)
* sin(2.0*betaS)) + ((23.0*es4/360.0 + 251.0*es6/3780.0) * sin(4.0*betaS))
+ ((761.0*es6/45360.0)*sin(6.0*betaS));
return Coordinates(rad2deg(lon), rad2deg(lat));
}