Subversion Repositories planix.SVN

#include <u.h>
#include <libc.h>
#include "map.h"

static struct coord stdp0, stdp1;
static double k;

static int
Xlambert(struct place *place, double *x, double *y)
{
        double r;
        if(place->nlat.l < -80.*RAD)
                return(-1);
        if(place->nlat.l > 89.*RAD)
                r = 0;  /* slovenly */
        else
                r = stdp0.c*exp(0.5*k*log(
                   (1+stdp0.s)*(1-place->nlat.s)/((1-stdp0.s)*(1+place->nlat.s))));
        if(stdp1.l<0.)
                r = -r;
        *x = - r*sin(k * place->wlon.l);
        *y = - r*cos(k * place->wlon.l);
        return(1);
}

proj
lambert(double par0, double par1)
{
        double temp;
        if(fabs(par0)>fabs(par1)){
                temp = par0;
                par0 = par1;
                par1 = temp;
        }
        deg2rad(par0, &stdp0);
        deg2rad(par1, &stdp1);
        if(fabs(par1+par0)<.1) 
                return(mercator());
        if(fabs(par1-par0)<.1)
                return(perspective(-1.));
        if(fabs(par0)>89.5||fabs(par1)>89.5)
                return(0);
        k = 2*log(stdp1.c/stdp0.c)/log(
                (1+stdp0.s)*(1-stdp1.s)/((1-stdp0.s)*(1+stdp1.s)));
        return(Xlambert);
}