public override PJ Init()
{
phi1 = Math.Abs(Proj.pj_param_r(ctx, parameters, "lat_ts"));
mode = phi1 > EPS;
if (mode)
{
fxb = 0.5 * Math.Sin(phi1);
fxa = 0.5 / fxb;
}
es = 0.0;
fwd = s_forward;
return(this);
}
public double proj_inv_mdist(projCtx ctx, double dist)
{
double k = 1.0 / (1.0 - es);
int i = MAX_ITER_mdist;
double phi = dist;
while (i-- > 0)
{
double s = Math.Sin(phi);
double t = 1.0 - es * s * s;
phi -= t = (proj_mdist(phi, s, Math.Cos(phi)) - dist) * (t * Math.Sqrt(t)) * k;
if (Math.Abs(t) < TOL14)
{
return(phi); // that is no change
}
}
// convergence failed
Proj.pj_ctx_set_errno(ctx, -17);
return(phi);
}