void
GeoMath::interpolate(double lat1Rad, double lon1Rad,
double lat2Rad, double lon2Rad,
double t,
double& out_latRad, double& out_lonRad)
{
static osg::EllipsoidModel em; // questionable. make non-static?
osg::Vec3d v0, v1;
em.convertLatLongHeightToXYZ(lat1Rad, lon1Rad, 0, v0.x(), v0.y(), v0.z());
double r0 = v0.length();
v0.normalize();
em.convertLatLongHeightToXYZ(lat2Rad, lon2Rad, 0, v1.x(), v1.y(), v1.z());
double r1 = v1.length();
v1.normalize();
osg::Vec3d axis = v0 ^ v1;
double angle = acos( v0 * v1 );
osg::Quat q( angle * t, axis );
v0 = (q * v0) * 0.5*(r0 + r1);
double dummy;
em.convertXYZToLatLongHeight( v0.x(), v0.y(), v0.z(), out_latRad, out_lonRad, dummy );
}
osg::Vec3d
Ephemeris::getECEFfromRADecl(double ra, double decl, double range) const
{
static const osg::EllipsoidModel WGS84;
osg::Vec3d out;
WGS84.convertLatLongHeightToXYZ(
decl, ra, range,
out.x(), out.y(), out.z());
return out;
}