Subversion Repositories planix.SVN

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

static int
Xmollweide(struct place *place, double *x, double *y)
{
        double z;
        double w;
        z = place->nlat.l;
        if(fabs(z)<89.9*RAD)
                do {    /*newton for 2z+sin2z=pi*sin(lat)*/
                        w = (2*z+sin(2*z)-PI*place->nlat.s)/(2+2*cos(2*z));
                        z -= w;
                } while(fabs(w)>=.00001);
        *y = sin(z);
        *x = - (2/PI)*cos(z)*place->wlon.l;
        return(1);
}

proj
mollweide(void)
{
        return(Xmollweide);
}