proj
lune(double lat, double theta)
{
deg2rad(lat, &eastpole.nlat);
deg2rad(-90.,&eastpole.wlon);
deg2rad(lat, &westpole.nlat);
deg2rad(90. ,&westpole.wlon);
Xstereographic(&eastpole, &eastx, &easty);
Xstereographic(&westpole, &westx, &westy);
if(fabs(easty)>FUZZ || fabs(westy)>FUZZ ||
fabs(eastx+westx)>FUZZ)
abort();
scale = 1/eastx;
pwr = theta/180;
return Xlune;
}
static int
Xlune(struct place *place, double *x, double *y)
{
double stereox, stereoy;
double z1x, z1y, z2x, z2y;
double w1x, w1y, w2x, w2y;
double numx, numy, denx, deny;
if(place->nlat.l < eastpole.nlat.l-FUZZ)
return -1;
Xstereographic(place, &stereox, &stereoy);
stereox *= scale;
stereoy *= scale;
z1x = 1 + stereox;
z1y = stereoy;
z2x = 1 - stereox;
z2y = -stereoy;
cpow(z1x,z1y,&w1x,&w1y,pwr);
cpow(z2x,z2y,&w2x,&w2y,pwr);
numx = w1x - w2x;
numy = w1y - w2y;
denx = w1x + w2x;
deny = w1y + w2y;
cdiv(numx, numy, denx, deny, x, y);
return 1;
}
static int
Xhex(struct place *place, double *x, double *y)
{
int ns;
int i;
double zr,zi;
double sr,si,tr,ti,ur,ui,vr,vi,yr,yi;
struct place p;
copyplace(place,&p);
ns = place->nlat.l >= 0;
if(!ns) {
p.nlat.l = -p.nlat.l;
p.nlat.s = -p.nlat.s;
}
if(p.nlat.l<HFUZZ) {
for(i=0;i<3;i++)
if(fabs(reduce(p.wlon.l-hcut[i]))<HFUZZ) {
if(i==2) {
*x = 2*cr[0] - cr[1];
*y = 0;
} else {
*x = cr[1];
*y = 2*ci[2*i];
}
return(1);
}
p.nlat.l = HFUZZ;
sincos(&p.nlat);
}
norm(&p,&hem,&twist);
Xstereographic(&p,&zr,&zi);
zr /= 2;
zi /= 2;
cdiv(1-zr,-zi,1+zr,zi,&sr,&si);
csq(sr,si,&tr,&ti);
ccubrt(1+3*tr,3*ti,&ur,&ui);
csqrt(ur-1,ui,&vr,&vi);
cdiv(rootroot3+vr,vi,rootroot3-vr,-vi,&yr,&yi);
yr /= rootk;
yi /= rootk;
elco2(fabs(yr),yi,hkc,1.,1.,x,y);
if(yr < 0)
*x = w2 - *x;
if(!ns) reflect(hcut[0]>place->wlon.l?0:
hcut[1]>=place->wlon.l?1:
2,*x,*y,x,y);
return(1);
}
int
Xtetra(struct place *place, double *x, double *y)
{
int i,j;
struct place pl;
register struct tproj *tpp;
double vr, vi;
double br, bi;
double zr,zi,z2r,z2i,z4r,z4i,sr,si,tr,ti;
twhichp(place,&i,&j);
copyplace(place,&pl);
norm(&pl,&tproj[i][j].projpl,&tproj[i][j].projtw);
Xstereographic(&pl,&vr,&vi);
zr = vr/2;
zi = vi/2;
if(zr<=TFUZZ)
zr = TFUZZ;
csq(zr,zi,&z2r,&z2i);
csq(z2r,z2i,&z4r,&z4i);
z2r *= two_rt3;
z2i *= two_rt3;
cdiv(z4r+z2r-1,z4i+z2i,z4r-z2r-1,z4i-z2i,&sr,&si);
csqrt(sr-1,si,&tr,&ti);
cdiv(tcon*tr,tcon*ti,root3+1-sr,-si,&br,&bi);
if(br<0) {
br = -br;
bi = -bi;
if(!elco2(br,bi,tk,1.,1.,&vr,&vi))
return 0;
vr = fpir - vr;
vi = fpii - vi;
} else
if(!elco2(br,bi,tk,1.,1.,&vr,&vi))
return 0;
if(si>=0) {
tr = f0r - vi;
ti = f0i + vr;
} else {
tr = f0r + vi;
ti = f0i - vr;
}
tpp = &tproj[i][j];
*x = tr*tpp->postrot.c +
ti*tpp->postrot.s + tx[i];
*y = ti*tpp->postrot.c -
tr*tpp->postrot.s + ty[i];
return(1);
}
