void fac(LP lp, ref FACTORS fac)
{
double sinphi=Math.Sin(lp.phi);
double cosphi=Math.Cos(lp.phi);
fac.code|=Factors.IS_ANAL_HK;
fac.h=1.0;
fac.k=n*(c-(ellips?Proj.pj_mlfn(lp.phi, sinphi, cosphi, en):lp.phi))/Proj.pj_msfn(sinphi, cosphi, es);
}
void fac(LP lp, ref FACTORS fac)
{
double rho=0.0;
if(Math.Abs(Math.Abs(lp.phi)-Proj.HALFPI)<EPS10)
{
if((lp.phi*n)<=0.0) return;
rho=0.0;
}
else rho=c*(ellips?Math.Pow(Proj.pj_tsfn(lp.phi, Math.Sin(lp.phi), e), n):Math.Pow(Math.Tan(Proj.FORTPI+0.5*lp.phi), -n));
fac.code|=Factors.IS_ANAL_HK+Factors.IS_ANAL_CONV;
fac.k=fac.h=k0*n*rho/Proj.pj_msfn(Math.Sin(lp.phi), Math.Cos(lp.phi), es);
fac.conv=-n*lp.lam;
}
public const int IS_ANAL_CONV = 010; // convergence analytic
public static bool pj_factors(LP lp, PJ P, double h, ref FACTORS fac)
{
IFactors PFac = P as IFactors;
const double EPS = 1.0e-12;
const double DEFAULT_H = 1e-5;
// check for forward and latitude or longitude overange
double t = Math.Abs(lp.phi) - Proj.HALFPI;
if (t > EPS || Math.Abs(lp.lam) > 10.0)
{
Proj.pj_ctx_set_errno(P.ctx, -14);
return(true);
}
// proceed
Libc.errno = Proj.pj_errno = 0;
P.ctx.last_errno = 0;
if (h < EPS)
{
h = DEFAULT_H;
}
if (Math.Abs(lp.phi) > (Proj.HALFPI - h))
{
lp.phi = lp.phi < 0.0?(-Proj.HALFPI + h):(Proj.HALFPI - h); // adjust to value around pi/2 where derived still exists
}
else if (P.geoc)
{
lp.phi = Math.Atan(P.rone_es * Math.Tan(lp.phi));
}
lp.lam -= P.lam0; // compute del lp.lam
if (!P.over)
{
lp.lam = Proj.adjlon(lp.lam); // adjust del longitude
}
if (PFac != null)
{
PFac.spc(lp, ref fac); // get what projection analytic values
}
if ((fac.code & (IS_ANAL_XL_YL + IS_ANAL_XP_YP)) != (IS_ANAL_XL_YL + IS_ANAL_XP_YP))
{
DERIVS der;
if (pj_deriv(lp, h, P, out der))
{
return(true);
}
if ((fac.code & IS_ANAL_XL_YL) == 0)
{
fac.der.x_l = der.x_l;
fac.der.y_l = der.y_l;
}
if ((fac.code & IS_ANAL_XP_YP) == 0)
{
fac.der.x_p = der.x_p;
fac.der.y_p = der.y_p;
}
}
double cosphi = Math.Cos(lp.phi);
double r;
if ((fac.code & IS_ANAL_HK) == 0)
{
fac.h = Libc.hypot(fac.der.x_p, fac.der.y_p);
fac.k = Libc.hypot(fac.der.x_l, fac.der.y_l) / cosphi;
if (P.es != 0)
{
t = Math.Sin(lp.phi);
t = 1.0 - P.es * t * t;
double n = Math.Sqrt(t);
fac.h *= t * n / P.one_es;
fac.k *= n;
r = t * t / P.one_es;
}
else
{
r = 1.0;
}
}
else if (P.es != 0)
{
r = Math.Sin(lp.phi);
r = 1.0 - P.es * r * r;
r = r * r / P.one_es;
}
else
{
r = 1.0;
}
// convergence
if ((fac.code & IS_ANAL_CONV) == 0)
{
fac.conv = -Math.Atan2(fac.der.y_l, fac.der.x_l);
if ((fac.code & IS_ANAL_XL_YL) != 0)
{
fac.code |= IS_ANAL_CONV;
}
}
// areal scale factor
fac.s = (fac.der.y_p * fac.der.x_l - fac.der.x_p * fac.der.y_l) * r / cosphi;
// meridian-parallel angle theta prime
fac.thetap = Proj.aasin(P.ctx, fac.s / (fac.h * fac.k));
// Tissot ellips axis
t = fac.k * fac.k + fac.h * fac.h;
fac.a = Math.Sqrt(t + 2.0 * fac.s);
t = (t = t - 2.0 * fac.s) <= 0.0?0.0:Math.Sqrt(t);
fac.b = 0.5 * (fac.a - t);
fac.a = 0.5 * (fac.a + t);
// omega
fac.omega = 2.0 * Proj.aasin(P.ctx, (fac.a - fac.b) / (fac.a + fac.b));
return(false);
}
public const int IS_ANAL_XP_YP = 02; // derivatives of lat analytic
#endregion Fields
#region Methods
public static bool pj_factors(LP lp, PJ P, double h, ref FACTORS fac)
{
IFactors PFac=P as IFactors;
const double EPS=1.0e-12;
const double DEFAULT_H=1e-5;
// check for forward and latitude or longitude overange
double t=Math.Abs(lp.phi)-Proj.HALFPI;
if(t>EPS||Math.Abs(lp.lam)>10.0)
{
Proj.pj_ctx_set_errno(P.ctx, -14);
return true;
}
// proceed
Libc.errno=Proj.pj_errno=0;
P.ctx.last_errno=0;
if(h<EPS) h=DEFAULT_H;
if(Math.Abs(lp.phi)>(Proj.HALFPI-h))
lp.phi=lp.phi<0.0?(-Proj.HALFPI+h):(Proj.HALFPI-h); // adjust to value around pi/2 where derived still exists
else if(P.geoc) lp.phi=Math.Atan(P.rone_es*Math.Tan(lp.phi));
lp.lam-=P.lam0; // compute del lp.lam
if(!P.over) lp.lam=Proj.adjlon(lp.lam); // adjust del longitude
if(PFac!=null) PFac.spc(lp, ref fac); // get what projection analytic values
if((fac.code&(IS_ANAL_XL_YL+IS_ANAL_XP_YP))!=(IS_ANAL_XL_YL+IS_ANAL_XP_YP))
{
DERIVS der;
if(pj_deriv(lp, h, P, out der)) return true;
if((fac.code&IS_ANAL_XL_YL)==0)
{
fac.der.x_l=der.x_l;
fac.der.y_l=der.y_l;
}
if((fac.code&IS_ANAL_XP_YP)==0)
{
fac.der.x_p=der.x_p;
fac.der.y_p=der.y_p;
}
}
double cosphi=Math.Cos(lp.phi);
double r;
if((fac.code&IS_ANAL_HK)==0)
{
fac.h=Libc.hypot(fac.der.x_p, fac.der.y_p);
fac.k=Libc.hypot(fac.der.x_l, fac.der.y_l)/cosphi;
if(P.es!=0)
{
t=Math.Sin(lp.phi);
t=1.0-P.es*t*t;
double n=Math.Sqrt(t);
fac.h*=t*n/P.one_es;
fac.k*=n;
r=t*t/P.one_es;
}
else r=1.0;
}
else if(P.es!=0)
{
r=Math.Sin(lp.phi);
r=1.0-P.es*r*r;
r=r*r/P.one_es;
}
else r=1.0;
// convergence
if((fac.code&IS_ANAL_CONV)==0)
{
fac.conv=-Math.Atan2(fac.der.y_l, fac.der.x_l);
if((fac.code&IS_ANAL_XL_YL)!=0) fac.code|=IS_ANAL_CONV;
}
// areal scale factor
fac.s=(fac.der.y_p*fac.der.x_l-fac.der.x_p*fac.der.y_l)*r/cosphi;
// meridian-parallel angle theta prime
fac.thetap=Proj.aasin(P.ctx, fac.s/(fac.h*fac.k));
// Tissot ellips axis
t=fac.k*fac.k+fac.h*fac.h;
fac.a=Math.Sqrt(t+2.0*fac.s);
t=(t=t-2.0*fac.s)<=0.0?0.0:Math.Sqrt(t);
fac.b=0.5*(fac.a-t);
fac.a=0.5*(fac.a+t);
// omega
fac.omega=2.0*Proj.aasin(P.ctx, (fac.a-fac.b)/(fac.a+fac.b));
return false;
}