public override PJ Init()
{
// get name of projection to be translated
string name = Proj.pj_param_s(ctx, parameters, "o_proj");
if (name == null || name == "")
{
Proj.pj_ctx_set_errno(ctx, -26); return(null);
}
link = Proj.GetPJ(name);
if (link == null)
{
Proj.pj_ctx_set_errno(ctx, -5); return(null);
}
// copy existing header into new
es = 0.0; // force to spherical
link.parameters = parameters;
link.ctx = ctx;
link.over = over;
link.geoc = geoc;
link.a = a;
link.es = es;
link.ra = ra;
link.lam0 = lam0;
link.phi0 = phi0;
link.x0 = x0;
link.y0 = y0;
link.k0 = k0;
// force spherical earth
link.one_es = link.rone_es = 1.0;
link.es = link.e = 0.0;
link = link.Init();
if (link == null)
{
return(null);
}
double phip = 0;
if (Proj.pj_param_t(ctx, parameters, "o_alpha"))
{
double lamc = Proj.pj_param_r(ctx, parameters, "o_lon_c");
double phic = Proj.pj_param_r(ctx, parameters, "o_lat_c");
double alpha = Proj.pj_param_r(ctx, parameters, "o_alpha");
//if(Math.Abs(phic)<=TOL10||Math.Abs(Math.Abs(phic)-HALFPI)<=TOL10||Math.Abs(Math.Abs(alpha)-HALFPI)<=TOL10)
if (Math.Abs(Math.Abs(phic) - Proj.HALFPI) <= TOL)
{
Proj.pj_ctx_set_errno(ctx, -32); return(null);
}
lamp = lamc + Proj.aatan2(-Math.Cos(alpha), -Math.Sin(alpha) * Math.Sin(phic));
phip = Proj.aasin(ctx, Math.Cos(phic) * Math.Sin(alpha));
}
else if (Proj.pj_param_t(ctx, parameters, "o_lat_p"))
{ // specified new pole
lamp = Proj.pj_param_r(ctx, parameters, "o_lon_p");
phip = Proj.pj_param_r(ctx, parameters, "o_lat_p");
}
else
{ // specified new "equator" points
double lam1 = Proj.pj_param_r(ctx, parameters, "o_lon_1");
double phi1 = Proj.pj_param_r(ctx, parameters, "o_lat_1");
double lam2 = Proj.pj_param_r(ctx, parameters, "o_lon_2");
double phi2 = Proj.pj_param_r(ctx, parameters, "o_lat_2");
double con = Math.Abs(phi1);
if (Math.Abs(phi1 - phi2) <= TOL || con <= TOL ||
Math.Abs(con - Proj.HALFPI) <= TOL || Math.Abs(Math.Abs(phi2) - Proj.HALFPI) <= TOL)
{
Proj.pj_ctx_set_errno(ctx, -33); return(null);
}
lamp = Math.Atan2(Math.Cos(phi1) * Math.Sin(phi2) * Math.Cos(lam1) - Math.Sin(phi1) * Math.Cos(phi2) * Math.Cos(lam2),
Math.Sin(phi1) * Math.Cos(phi2) * Math.Sin(lam2) - Math.Cos(phi1) * Math.Sin(phi2) * Math.Sin(lam1));
phip = Math.Atan(-Math.Cos(lamp - lam1) / Math.Tan(phi1));
}
if (Math.Abs(phip) > TOL)
{ // oblique
cphip = Math.Cos(phip);
sphip = Math.Sin(phip);
fwd = o_forward;
inv = link.inv != null?o_inverse:(LP_XY_PJ)null;
}
else
{ // transverse
fwd = t_forward;
inv = link.inv != null?t_inverse:(LP_XY_PJ)null;
}
return(this);
}
