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GPXSee/src/map/datum.cpp

129 lines
3.7 KiB
C++

#include "common/wgs84.h"
#include "datum.h"
#define as2rad(x) ((x) * (M_PI/648000.0))
#define rad2as(x) ((x) * (648000.0/M_PI))
#define ds2scale(x) (1.0 + (x) * 1e-6)
#define scale2ds(x) (((x) - 1.0) / 1e-6)
static Coordinates molodensky(const Coordinates &c, const Datum &from,
const Datum &to)
{
double rlat = deg2rad(c.lat());
double rlon = deg2rad(c.lon());
double slat = sin(rlat);
double clat = cos(rlat);
double slon = sin(rlon);
double clon = cos(rlon);
double ssqlat = slat * slat;
double dx = from.dx() - to.dx();
double dy = from.dy() - to.dy();
double dz = from.dz() - to.dz();
double from_f = from.ellipsoid().flattening();
double to_f = to.ellipsoid().flattening();
double df = to_f - from_f;
double from_a = from.ellipsoid().radius();
double to_a = to.ellipsoid().radius();
double da = to_a - from_a;
double from_esq = from_f * (2.0 - from_f);
double adb = 1.0 / (1.0 - from_f);
double rn = from_a / sqrt(1 - from_esq * ssqlat);
double rm = from_a * (1 - from_esq) / pow((1 - from_esq * ssqlat), 1.5);
double dlat = (-dx * slat * clon - dy * slat * slon + dz * clat + da
* rn * from_esq * slat * clat / from_a + df * (rm * adb + rn / adb) * slat
* clat) / rm;
double dlon = (-dx * slon + dy * clon) / (rn * clat);
return Coordinates(c.lon() + rad2deg(dlon), c.lat() + rad2deg(dlat));
}
const Datum &Datum::WGS84()
{
static Datum d(Ellipsoid::WGS84(), 0.0, 0.0, 0.0);
return d;
}
Point3D Datum::helmert(const Point3D &p) const
{
return Point3D(_scale * (p.x() + _rz * p.y() -_ry * p.z()) + _dx,
_scale * (-_rz * p.x() + p.y() + _rx * p.z()) + _dy,
_scale * (_ry * p.x() -_rx * p.y() + p.z()) + _dz);
}
Point3D Datum::helmertr(const Point3D &p) const
{
double x = (p.x() - _dx) / _scale;
double y = (p.y() - _dy) / _scale;
double z = (p.z() - _dz) / _scale;
return Point3D(x -_rz * y + _ry * z, _rz * x + y + -_rx * z, -_ry * x + _rx
* y + z);
}
Datum::Datum(const Ellipsoid &ellipsoid, double dx, double dy, double dz,
double rx, double ry, double rz, double ds)
: _ellipsoid(ellipsoid), _dx(dx), _dy(dy), _dz(dz), _rx(as2rad(rx)),
_ry(as2rad(ry)), _rz(as2rad(rz)), _scale(ds2scale(ds))
{
if (_ellipsoid.radius() == WGS84_RADIUS && _ellipsoid.flattening()
== WGS84_FLATTENING && _dx == 0.0 && _dy == 0.0 && _dz == 0.0
&& _rx == 0.0 && _ry == 0.0 && _rz == 0.0 && ds == 0.0)
_transformation = None;
else
_transformation = Helmert;
}
Datum::Datum(const Ellipsoid &ellipsoid, double dx, double dy, double dz)
: _ellipsoid(ellipsoid), _dx(dx), _dy(dy), _dz(dz), _rx(0.0), _ry(0.0),
_rz(0.0), _scale(1.0)
{
if (_ellipsoid.radius() == WGS84_RADIUS && _ellipsoid.flattening()
== WGS84_FLATTENING && _dx == 0.0 && _dy == 0.0 && _dz == 0.0)
_transformation = None;
else
_transformation = Molodensky;
}
Coordinates Datum::toWGS84(const Coordinates &c) const
{
switch (_transformation) {
case Helmert:
return Geocentric::toGeodetic(helmert(Geocentric::fromGeodetic(c,
ellipsoid())), WGS84().ellipsoid());
case Molodensky:
return molodensky(c, *this, WGS84());
default:
return c;
}
}
Coordinates Datum::fromWGS84(const Coordinates &c) const
{
switch (_transformation) {
case Helmert:
return Geocentric::toGeodetic(helmertr(Geocentric::fromGeodetic(c,
WGS84().ellipsoid())), ellipsoid());
case Molodensky:
return molodensky(c, WGS84(), *this);
default:
return c;
}
}
#ifndef QT_NO_DEBUG
QDebug operator<<(QDebug dbg, const Datum &datum)
{
dbg.nospace() << "Datum(" << datum.ellipsoid() << ", " << datum.dx()
<< ", " << datum.dy() << ", " << datum.dz() << ", " << rad2as(datum.rx())
<< ", " << rad2as(datum.ry()) << ", " << rad2as(datum.rz()) << ", "
<< scale2ds(datum.scale()) << ")";
return dbg.space();
}
#endif // QT_NO_DEBUG