Subversion Repositories planix.SVN

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

static int
Xlagrange(struct place *place, double *x, double *y)
{
        double z1,z2;
        double w1,w2,t1,t2;
        struct place p;
        copyplace(place,&p);
        if(place->nlat.l<0) {
                p.nlat.l = -p.nlat.l;
                p.nlat.s = -p.nlat.s;
        }
        Xstereographic(&p,&z1,&z2);
        csqrt(-z2/2,z1/2,&w1,&w2);
        cdiv(w1-1,w2,w1+1,w2,&t1,&t2);
        *y = -t1;
        *x = t2;
        if(place->nlat.l<0)
                *y = -*y;
        return(1);
}

proj
lagrange(void)
{
        return(Xlagrange);
}