Improvement of PSTricks code for drawing of Pantheon

Question

Consider the following example.

Code

% pdflatex -shell-escape test.tex

\documentclass{article}

\usepackage{
  auto-pst-pdf,
  pst-eucl,
  pstricks-add
}
\usepackage[
  locale=DE
]{siunitx}

\begin{document}

\begin{figure}
\def\radius{21.65 }      % radius
\def\vinkelA{12 }        % angle
\def\faktor{0.33333333 } % scaling
\newlength\maksimum      % define length
\maksimum=\radius\psunit % set the length to the current value/unit
\maksimum=2\dimexpr\faktor\maksimum
 \centering
 \psset{
   unit=0.8cm,
   linecolor=red
 }
  \begin{pspicture}(\maksimum,\maksimum)
   \pnode(!2 \faktor \radius mul mul \faktor \radius mul){A}
   \pnode(!\faktor \radius mul \faktor \radius mul){B}
   \pnode(!\faktor \radius mul 1 \vinkelA cos add \faktor \radius mul mul){C}
   \psline(A)(!2 \faktor \radius mul mul 0)(0,0)(!0 \faktor \radius mul)
   \psarc(B){!\faktor \radius mul}{0}{!90 \vinkelA sub}
   \psarc(B){!\faktor \radius mul}{!90 \vinkelA add}{180}
   \psline[linestyle=dashed](!0 \faktor \radius mul)(A)
   \psarc[linestyle=dashed](B){!\faktor \radius mul}{180}{360}
  \psset{
    linecolor=blue,
    linewidth=1.5pt
  }
   \psRelLine[angle=!270 \vinkelA add](B)(!0 \faktor \radius mul){1}{P1}
   \psRelLine[angle=!90 \vinkelA sub](B)(A){1}{P2}
   \pcline(B)(P1)
   \pcline(B)(P2)
   \pcline[linestyle=none](P1)(P2)
   \aput*{:U}{Oculus}
   \pcline(P1)(P2)
   \pcline(B)(C)
  \psset{
    linecolor=black,
    linewidth=0.5pt,
    MarkAngleRadius=3.7,
    LabelSep=4
  }
   \psRelLine[linestyle=dotted,angle=45]{<->}(B)(A){1}{V}
   \ncline[linestyle=none]{B}{V}
   \naput[nrot=:U]{\small\SI{\radius}{\m}}
   \pstMarkAngle{C}{B}{P1}{\scriptsize\SI{\vinkelA}{\degree}}
   \pstMarkAngle{P2}{B}{C}{\scriptsize\SI{\vinkelA}{\degree}}
   \pstRightAngle{P1}{C}{B}
   \pstRightAngle{P2}{C}{B}
  \end{pspicture}
\end{figure}

\end{document}

Output

Question

I would like to improve the code. I have already improved it somewhat from where I started, but I can quite clearly get even better.

Answer 1

\documentclass{article}
\usepackage{auto-pst-pdf,pst-node}

\begin{document}
\psset{unit=3mm}
\def\radius{21.65 }      % radius
\def\vinkelA{12 }        % angle

\begin{pspicture}(-\radius,-\radius)(\radius,\radius)
  \psarc[linestyle=dashed,linecolor=red](0,0){\radius}{180}{360}
  \psarc[linecolor=red](0,0){\radius}{0}{!90 \vinkelA sub}
  \psarc[linecolor=red](0,0){\radius}{!90 \vinkelA add}{180}
  \psline[linecolor=red](-\radius,0)(-\radius,-\radius)(\radius,-\radius)(\radius,0)
  \psline[linecolor=red,linestyle=dashed](-\radius,0)(\radius,0)
  \psarc(0,0){!\radius 2 div}{!90 \vinkelA sub}{!90 \vinkelA add}
  \uput[90](!\radius 2 div 90 \vinkelA 2 div sub PtoC){$\vinkelA^\circ$}
  \uput[90](!\radius 2 div 90 \vinkelA 2 div add PtoC){$\vinkelA^\circ$}
  \pnode(!0 \radius \vinkelA cos mul){Oculus}
  \pspolygon[linecolor=blue,linewidth=1.5pt,linejoin=1]%
    (!\radius 90 \vinkelA add PtoC)(0,0)(!\radius 90 \vinkelA sub PtoC)
  \psline[linecolor=blue,linewidth=1.5pt](Oculus)
  \psline[linestyle=dotted]{<->}(\radius;45)
  \uput[90]{45}(!\radius 2 div 45 PtoC){\radius}
  \uput[90](0,\radius){Oculus}
  \rput[t](Oculus){\psline(-1.5,0)(-1.5,-1.5)(1.5,-1.5)(1.5,0)}
\end{pspicture}

\end{document}