\documentclass{minimal}
\usepackage{tikz}
\begin{document}
\centering
\begin{tikzpicture}
  [endpoint/.style={scale=0.5,fill,rectangle},
  point/.style={scale=0.5,fill,circle}]
  \node[endpoint,name=sw0] at (0,0) {};
  \node[endpoint,name=sw1] at (5,0) {};
  \node[endpoint,name=swn0] at (0,-2) {};
  \node[endpoint,name=swn1] at (5,-2) {};
  
  \node[point,name=swir] at (0.5,0) {};
  \node[point,name=sorw] at (4.1,0) {};
  \node[point,name=sw] at (3,0) {};
  \node[point,name=swn] at (3.4722,-2) {}; % Calculated
  
  \node[below] at (swir) {$S_{wir}$};
  \node[below,xshift=12,yshift=-5] at (sorw) {$S_{orw}$};
  \node[below] at (sw) {$S_w$};
  \node[below] at (swn) {$S_{wn}$};
  \draw[,|<->|,yshift=-5] (4.1,0) -- (5,0);
  
  \draw[thick,shorten <=12,shorten >=0.5,blue,->] (swir) -- (swn0);
  \draw[thick,shorten <=18,shorten >=0.5,blue,->] (sorw) -- (swn1);
  \draw[thick,shorten <=12,shorten >=0.5,blue,->] (sw) -- (swn);
  
  \node[above] at (sw0.north) {$S_w=0$};
  \node[above] at (sw1.north) {$S_w=1$};
  \node[below] at (swn0.south) {$S_{wn} = 0$};
  \node[below] at (swn1.south) {$S_{wn} = 1$};
  
  
  \draw[thick] (sw0) -- (sw1);
  
  \draw[thick] (swn0) -- (swn1);
\end{tikzpicture}
\end{document}