latex-pictures

A collection of TikZ drawings and other images 🖌️

stereographic-projection.tikz (889B)

 1 % This picture represents the stereographic projection
 2 % Copyright Pablo (C) 2021
 3 \begin{tikzpicture}[scale=0.4]
 4   % The outline of the sphere
 5   \draw (0, 0) circle (3);
 6 
 7   % The equator
 8   \begin{scope}
 9     \clip (-3, 0) rectangle (3, -3);
10     \draw ellipse (3 and 1);
11   \end{scope}
12 
13   % The equator (on the other side of the sphere)
14   \begin{scope}
15     \clip (-3, 0) rectangle (3, 3);
16     \draw[dotted] ellipse (3 and 1);
17   \end{scope}
18 
19   % The plane
20   \draw (-9, -4) -- (-5,  0) 
21                  -- (-3,  0) 
22         ( 3,  0) -- ( 9,  0) 
23                  -- ( 5, -4) 
24                  -- (-9, -4);
25 
26   % A line trought the sphere and the plane
27   \coordinate (N) at (0,  3);
28   \coordinate (a) at (2, -1);
29   \coordinate (b) at (3, -3);
30   \draw[dotted] (N) -- (a);
31   \draw         (a) -- (b);
32 
33   % The dots
34   \filldraw (N) circle (2pt) (a) circle (2pt) (b) circle (2pt);
35 \end{tikzpicture}