如何在球体上绘制经线

Question

以下是我目前所掌握的信息：

\documentclass{article}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\fill[ball color=blue!20] (0,0) circle (1.5 cm);
\newcommand\longitude[1]{%
  \draw (#1:1.5) arc (0:-180:{1.5*cos(#1)} and {0.2*cos(#1)});
  \draw[dashed] (#1:1.5) arc (0:180:{1.5*cos(#1)} and {0.2*cos(#1)});
}
\longitude{30};
\longitude{0};
\longitude{-30};
\end{tikzpicture}
\end{document}

但是这会绘制纬线而不是经线。我的目标是让图表看起来像这样：

Answer 1

TeXample.net可以是一个很好的资源。以下是改编自蒲公英球例子。

\documentclass[border=2mm]{standalone}
\usepackage{tikz}
\tikzset{
    MyPerspective/.style={scale=1.8,x={(-1cm,0cm)},y={(1cm,0cm)},
    z={(0cm,1.2cm)}}
        }
\begin{document}
\begin{tikzpicture}[MyPerspective]
        \foreach \t in {0,15,...,165}% meridians
            {\draw[gray] ({cos(\t)},{sin(\t)},0)
                \foreach \rho in {5,10,...,360}
                    {--({cos(\t)*cos(\rho)},{sin(\t)*cos(\rho)},
          {sin(\rho)})};
            }
\end{tikzpicture}
\end{document}