%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% PhS
%%

%% échelle et étendue de l'image
60 setxunit
-3.5 3.5  setxrange
-3 4 setyrange


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%  DANGER !! Il ne faut pas utiliser de variables
%%  DANGER !! qui commence par les lettres :
%%  DANGER !! xmin, xmax, ymin et ymax...
%%  DANGER !! Utiliser x_min, y_min...
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% procédures
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


%% procedure sphere_parallele
/parallele_de_sphere { %% R (rayon) phi (lattitude deg) alpha 
(inclinaison deg)
6 dict begin
    /alpha exch def
    /phi exch def
    /R exch def
    /Xdet {
    1 dict begin
        /t exch def
        R phi sin mul t cos mul
    end
    } def
    /Ydet {
    1 dict begin
        /t exch def
        phi cos alpha cos mul phi sin alpha sin mul t sin mul sub R mul
    end
    } def
    90 phi eq
      {/phi phi 1.001 mul def}
    if
    1 alpha tan phi tan div lt
      {/tmax -90 def}
      { alpha tan phi tan div -1 lt
        {/tmax 90 def}
        {/tmax alpha tan phi tan div neg arcsin def}
      ifelse}
    ifelse
    gsave
    tmax dup neg 180 add settrange
    {Xdet} {Ydet} courbeparam
    grestore
end
    } def



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% définitions des couleurs
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

/coul1 {120 255 div 70 255 div 9 255 div setrgbcolor} def



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% tracés
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%% tracé des axes et du point Origine
1 setlinewidth
15 setfontsize
noir
continu
traceaxes
marks
tracerepere



rouge
0 0 3 cercle

coul1
3 5 30 parallele_de_sphere
3 15 30 parallele_de_sphere
3 25 30 parallele_de_sphere

3 30 30 parallele_de_sphere
3 40 30 parallele_de_sphere
3 50 30 parallele_de_sphere
3 60 30 parallele_de_sphere
3 70 30 parallele_de_sphere
3 80 30 parallele_de_sphere
3 90 30 parallele_de_sphere
3 100 30 parallele_de_sphere
3 110 30 parallele_de_sphere
3 140 30 parallele_de_sphere

3 155 30 parallele_de_sphere
3 165 30 parallele_de_sphere
3 175 30 parallele_de_sphere