I need to input in my document this kind of images. How to 1. draw this image? 2. set its position to text? 3. enumerate and give name, to refer to its number?

This is a possible solution via tikz-3dplot, to serve as a starting point.

code
\documentclass[border=10pt]{standalone}
\usepackage{tikz,amsmath}
\usepackage{tikz-3dplot}
\usetikzlibrary{shapes,calc,positioning}
\usetikzlibrary{calc,intersections}
\begin{document}
\tdplotsetmaincoords{90}{90}
\begin{tikzpicture}[scale=5,tdplot_main_coords]
% draw various ellipses
\tdplotsetthetaplanecoords{90}
\tdplotdrawarc[tdplot_rotated_coords,thick]{(0,0,0)}{0.8}{0}{360}{}{}
%
\tdplotsetrotatedcoords{60}{70}{0}
\tdplotdrawarc[dashed,tdplot_rotated_coords,name path=blue]{(0,0,0)}{0.8}{0}{360}{below}{$\alpha_2$}
\tdplotdrawarc[tdplot_rotated_coords]{(0,0,0)}{0.8}{0}{180}{above right}{$\alpha_1$}
%
\tdplotsetrotatedcoords{120}{110}{0}
\tdplotdrawarc[dashed,tdplot_rotated_coords,name path=green]{(0,0,0)}{0.8}{0}{360}{below}{$\beta$}
\tdplotdrawarc[tdplot_rotated_coords]{(0,0,0)}{0.8}{0}{180}{left}{$\mathcal A_2$}
%
\tdplotsetrotatedcoords{180}{16}{0}
\tdplotdrawarc[dashed,tdplot_rotated_coords,name path=red]{(0,0,0)}{0.8}{0}{360}{above left}{$\zeta$}
\tdplotdrawarc[tdplot_rotated_coords]{(0,0,0)}{0.8}{-90}{90}{below left}{$\gamma$}
% find intersections
\path [name intersections={of={green and blue}, total=\n}]
\foreach \i in {1,...,\n}{(intersection-\i) circle [radius=0.5pt] coordinate(gb\i){}};
\path [name intersections={of={green and red}, total=\n}]
\foreach \i in {1,...,\n} {(intersection-\i) circle [radius=0.5pt]coordinate(gc\i){}};
\path[name intersections={of={red and blue}, total=\n}]
\foreach \i in {1,...,\n}{(intersection-\i) circle [radius=0.5pt]coordinate(cb\i){}};
% shading
\shade[top color=gray,bottom color=white,opacity=0.5]
(cb4) to[bend left=7] (gc1) to[bend left=15] (gb2) to[bend left=15] cycle;
% label
\draw[dashed,fill] (gb2) circle [radius=0.5pt]--(gb4) circle [radius=0.5pt];
\draw[dashed, fill] (cb2) circle [radius=0.5pt]--(cb4)circle [radius=0.5pt];
\draw[dashed,fill] (gc1) circle [radius=0.5pt]--(gc3) circle [radius=0.5pt];
\draw[dashed,fill] (gb2) circle [radius=0.5pt]--(cb4) circle [radius=0.5pt];
\draw (gb2) node[below]{$\mathcal C$};
\draw (gc1) node[above right]{$\mathcal A_1$};
\draw (cb4) node[above left]{$\mathcal B$};
\draw[] (gc1) to[bend left=30] ++(1,0.71,0.5)node(a){};
\draw[dashed,fill] (a) circle [radius=0.5pt]--(gc1)circle [radius=0.5pt];
\coordinate (O) at (0,0,0);
\draw[thick,->] (0,0,0) -- (1,0,0) node[anchor=north east]{$X$};
\draw[thick,->] (0,0,0) -- (0,1,0) node[anchor=north west]{$Y$};
\draw[thick,->] (0,0,0) -- (0,0,1) node[anchor=south]{$Z$};
\end{tikzpicture}
\end{document}
to[bend left=xx] with --. For complex surface (3D), clip are often used, but usually not an easy task.
– Jesse
Feb 28 '15 at 15:06
\begin{figure}\includegraphics[width=\linewidth,height=0.75\textheight,keepaspectratio]{sphereimagefile}\caption{Sphere}\label{fig:sphere}\end{figure}– musarithmia Feb 27 '15 at 16:49