func (cs *CoordinateSystem) Inverse(xyz *globals.XYZ) *globals.PLH {
xyz.X = (xyz.X*cs.FloatParams["to_meter"] - cs.FloatParams["x_0"]) * cs.FloatParams["ra"]
xyz.Y = (xyz.Y*cs.FloatParams["to_meter"] - cs.FloatParams["y_0"]) * cs.FloatParams["ra"]
plh := cs.Projection.Inverse(cs.FloatParams, xyz)
plh.Lam = plh.Lam + cs.FloatParams["lam0"]
if !cs.BoolParams["over"] {
plh.Lam = cs.adjlon(plh.Lam)
}
return plh
}
func StereaInverse(params map[string]float64, xyz *globals.XYZ) *globals.PLH { // x, y float64) (lat, lon float64) {
splh := &globals.PLH{}
// sterea
const MAX_ITER = 20
const DEL_TOL = 1e-14
xyz.X = xyz.X / params["k"]
xyz.Y = xyz.Y / params["k"]
rho := math.Hypot(xyz.X, xyz.Y)
if rho != 0 {
c := 2.0 * math.Atan2(rho, params["2R"])
sinc := math.Sin(c)
cosc := math.Cos(c)
splh.Phi = math.Asin(cosc*params["sinc0"] + xyz.Y*sinc*params["cosc0"]/rho)
splh.Lam = math.Atan2(xyz.X*sinc, rho*params["cosc0"]*cosc-xyz.Y*params["sinc0"]*sinc)
} else {
splh.Phi = params["latc0"]
splh.Lam = 0.0
}
// inv_gaus
eplh := &globals.PLH{}
eplh.Lam = splh.Lam / params["C"]
num := math.Pow(math.Tan(0.5*splh.Phi+globals.PI_OVER_4)/params["K"], 1.0/params["C"])
var i uint8
for i = 0; i < MAX_ITER; i++ {
eplh.Phi = 2.0*math.Atan(num*srat(params["e"]*math.Sin(splh.Phi), -0.5*params["e"])) - globals.PI_OVER_2
if math.Abs(eplh.Phi-splh.Phi) < DEL_TOL {
break
}
splh.Phi = eplh.Phi
}
if i == MAX_ITER-1 {
fmt.Printf("Convergence failed")
}
eplh.Height = xyz.Z
return eplh
}