Summary

Abaque de Wulff avec un pas de 2 °, pour la lecture de figure de pôles

Wulff net with a step of 2°, used to read pole figures

Voir aussi/see also : image:abaque wulff.png

Auteur/author : Christophe Dang Ngoc Chan (cdang)

Réalisé avec/made with : Scilab

clear;clf;
pas=0.005;

// Cercle horizontal de base

y=[0:pas:1]';
NY=size(y); ny=NY(1,1);

for i=1:ny
   x(i)=sqrt(1-y(i)^2);
end

// Cercles méridiens et parallèles

for j=1:44
   r1=cos(j*%pi/90); // décalage de 2°
   r2=sin(j*%pi/90);
   for i=1:ny
// Cercles méridiens
      Xm(i,j)=x(i)*r1; // coordonnées des points du cercle incliné
      Ym(i,j)=y(i);
      Zm(i,j)=x(i)*r2;
// Cercles parallèles
      Xp(i,j)=y(i)*r2; // coordonnées des points du cercle parallèle
      Yp(i,j)=r1;
      Zp(i,j)=x(i)*r2;
   end
end


// Projection stéréographique

// Pôle Sud S(0,0,-1), pôle P(X1,Y,Z)
// Droite : S + m*SP = (m*X1)i + (m*Y)j + (-1+m*(Z+1))k

for j=1:44
   for i=1:ny
// Cercles méridiens
      mm = 1/(1+Zm(i,j)); // z=0
      Xm1(i,j)=mm*Xm(i,j);
      Ym1(i,j)=mm*Ym(i,j);
// Cercles parallèles
      mp = 1/(1+Zp(i,j)); // z=0
      Xp1(i,j)=mp*Xp(i,j);
      Yp1(i,j)=mp*Yp(i,j);
   end
end

// Tracé

// Méridiens : simplifié près des extrémités (10°)

k=int((1-cos(%pi/18))/pas);
l=int((1-cos(%pi/90))/pas);
if l=0 then l=1; end

// Graduations par 2°

for j=[[1:4],[6:9],[11:14],[16:19],[21:24],[26:29],[31:34],[16:39],[41:44]]

   plot2d(Xm1(1:ny-k,j),Ym1(1:ny-k,j),style=2)
   plot2d(-Xm1(1:ny-k,j),Ym1(1:ny-k,j),style=2)
   plot2d(Xm1(1:ny-k,j),-Ym1(1:ny-k,j),style=2)
   plot2d(-Xm1(1:ny-k,j),-Ym1(1:ny-k,j),style=2)
   
   plot2d(Xp1(:,j),Yp1(:,j),style=2)
   plot2d(-Xp1(:,j),Yp1(:,j),style=2)
   plot2d(Xp1(:,j),-Yp1(:,j),style=2)
   plot2d(-Xp1(:,j),-Yp1(:,j),style=2)

end

// Graduations principales

for j=5:5:44

   xpoly(Xm1(1:ny-k,j),Ym1(1:ny-k,j))
   a=get('hdl');a.thickness=2;
   xpoly(-Xm1(1:ny-k,j),Ym1(1:ny-k,j))
   a=get('hdl');a.thickness=2;
   xpoly(Xm1(1:ny-k,j),-Ym1(1:ny-k,j))
   a=get('hdl');a.thickness=2;
   xpoly(-Xm1(1:ny-k,j),-Ym1(1:ny-k,j))
   a=get('hdl');a.thickness=2;
   plot2d(Xm1(ny-k:ny-l,j),Ym1(ny-k:ny-l,j))
   plot2d(-Xm1(ny-k:ny-l,j),Ym1(ny-k:ny-l,j))
   plot2d(Xm1(ny-k:ny-l,j),-Ym1(ny-k:ny-l,j))
   plot2d(-Xm1(ny-k:ny-l,j),-Ym1(ny-k:ny-l,j))

   xpoly(Xp1(:,j),Yp1(:,j))
   a=get('hdl');a.thickness=2;
   xpoly(-Xp1(:,j),Yp1(:,j))
   a=get('hdl');a.thickness=2;
   xpoly(Xp1(:,j),-Yp1(:,j))
   a=get('hdl');a.thickness=2;
   xpoly(-Xp1(:,j),-Yp1(:,j))
   a=get('hdl');a.thickness=2;

end

// axes et cercle autour

plot2d(x,y)
plot2d(-x,y)
plot2d(x,-y)
plot2d(-x,-y)

xpoly([0,0],[-1,1])
a=get('hdl');a.thickness=2;
xpoly([-1,1],[0,0])
a=get('hdl');a.thickness=2;

axe=get('current_axes');
axe.axes_visible=['off','off'];
axe.isoview='on';
axe.box='off';

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