Subversion Repositories planix.SVN

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

int
Xpolyconic(struct place *place, double *x, double *y)
{
        double r, alpha;
        double lat2, lon2;
        if(fabs(place->nlat.l) > .01) {
                r = place->nlat.c / place->nlat.s;
                alpha = place->wlon.l * place->nlat.s;
                *y = place->nlat.l + r*(1 - cos(alpha));
                *x = - r*sin(alpha);
        } else {
                lon2 = place->wlon.l * place->wlon.l;
                lat2 = place->nlat.l * place->nlat.l;
                *y = place->nlat.l * (1+(lon2/2)*(1-(8+lon2)*lat2/12));
                *x = - place->wlon.l * (1-lat2*(3+lon2)/6);
        }
        return(1);
}

proj
polyconic(void)
{
        return(Xpolyconic);
}