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83 lines
2.6 KiB
C++
83 lines
2.6 KiB
C++
#include "ellipsoid.h"
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#include "obliquestereographic.h"
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#define S1(x) ((1.0 + x) / (1.0 - x))
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#define S2(x) ((1.0 - _e * x) / (1.0 + _e * x))
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ObliqueStereographic::ObliqueStereographic(const Ellipsoid *ellipsoid,
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double latitudeOrigin, double longitudeOrigin, double scale,
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double falseEasting, double falseNorthing)
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: _FE(falseEasting), _FN(falseNorthing)
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{
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double lat0 = deg2rad(latitudeOrigin);
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double sinPhi0 = sin(lat0);
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double cosPhi0 = cos(lat0);
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double sinLat0s = sinPhi0 * sinPhi0;
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double a = ellipsoid->radius();
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_es = ellipsoid->es();
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_e = sqrt(_es);
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double rho0 = a * (1.0 - _es) / pow(1.0 - _es * sinLat0s, 1.5);
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double nu0 = a / sqrt(1.0 - _es * sinLat0s);
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_n = sqrt(1.0 + ((_es * pow(cosPhi0, 4)) / (1.0 - _es)));
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double w1 = pow(S1(sinPhi0) * pow(S2(sinPhi0), _e), _n);
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double sinChi0 = (w1 - 1) / (w1 + 1);
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_c = (_n + sinPhi0) * (1.0 - sinChi0) / ((_n - sinPhi0) * (1.0 + sinChi0));
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double w2 = _c * w1;
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_chi0 = asin((w2 - 1.0)/(w2 + 1.0));
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_sinChi0 = sin(_chi0); _cosChi0 = cos(_chi0);
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_lambda0 = deg2rad(longitudeOrigin);
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_twoRk0 = 2.0 * sqrt(rho0 * nu0) * scale;
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_g = _twoRk0 * tan(M_PI_4 - _chi0 / 2.0);
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_h = 2.0 * _twoRk0 * tan(_chi0) + _g;
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}
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PointD ObliqueStereographic::ll2xy(const Coordinates &c) const
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{
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double lon = deg2rad(c.lon());
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double lat = deg2rad(c.lat());
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double sinPhi = sin(lat);
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double w = _c * pow(S1(sinPhi) * pow(S2(sinPhi), _e), _n);
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double chi = asin((w - 1.0) / (w + 1.0));
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double lambda = _n * (lon - _lambda0) + _lambda0;
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double B = (1.0 + sin(chi) * _sinChi0 + cos(chi) * _cosChi0
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* cos(lambda - _lambda0));
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return PointD(_FE + _twoRk0 * cos(chi) * sin(lambda - _lambda0) / B,
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_FN + _twoRk0 * (sin(chi) * _cosChi0 - cos(chi) * _sinChi0
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* cos(lambda - _lambda0)) / B);
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}
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Coordinates ObliqueStereographic::xy2ll(const PointD &p) const
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{
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double i = atan((p.x() - _FE) / (_h + (p.y() - _FN)));
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double j = atan((p.x() - _FE) / (_g - (p.y() - _FN))) - i;
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double chi = _chi0 + 2.0 * atan(((p.y() - _FN) - (p.x() - _FE) * tan(j/2.0))
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/ _twoRk0);
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double lambda = j + 2.0 * i + _lambda0;
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double psi0 = 0.5 * log((1.0 + sin(chi)) / (_c * (1.0 - sin(chi)))) / _n;
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double phi1 = 2.0 * atan(pow(M_E, psi0)) - M_PI_2;
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double psi, phi = phi1, prev = phi;
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for (int i = 0; i < 8; i++) {
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double sinPhi = sin(phi);
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psi = log((tan(phi/2.0 + M_PI_4)) * pow((1.0 - _e * sinPhi)
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/ (1.0 + _e * sinPhi), _e/2.0));
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phi = phi - (psi - psi0) * cos(phi) * (1.0 - _es * sinPhi * sinPhi)
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/ (1.0 - _es);
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if (fabs(phi - prev) < 1e-10)
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break;
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prev = phi;
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}
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return Coordinates(rad2deg((lambda - _lambda0) / _n + _lambda0),
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rad2deg(phi));
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}
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