I am trying to re-create the following horizontal timeline chart. I found some related examples, but nothing really close to do what I need (also perhaps for lack of correct naming of the chart itself). Thanks for any input on this.
UPDATE:
This is what I managed to produce (source):

by using:
\documentclass[a4paper,10pt]{article}
\usepackage{tikz}
\usepackage{verbatim}
\usepackage[active,tightpage]{preview}
\PreviewEnvironment{tikzpicture}
\setlength\PreviewBorder{5pt}%
\usetikzlibrary{arrows,chains,matrix,positioning,scopes}
\makeatletter
\tikzset{join/.code=\tikzset{after node path={%
\ifx\tikzchainprevious\pgfutil@empty\else(\tikzchainprevious)%
edge[every join]#1(\tikzchaincurrent)\fi}}}
\makeatother
\tikzset{>=stealth',every on chain/.append style={join},
every join/.style={->}}
\tikzstyle{labeled}=[execute at begin node=$\scriptstyle,
execute at end node=$]
%
\begin{document}
\begin{tikzpicture}
\matrix (m) [matrix of math nodes, row sep=3em, column sep=3em]
{ group \, 1 & N & \phantom{N} & M & S,M & \phantom{S,M} \\
group \, 2 & N & S,M & & \phantom{S,M} & \phantom{S,M} \\ };
{ [start chain] \chainin (m-1-2);
\chainin (m-1-4); %[join={node[above,labeled] {\psi}}];
\chainin (m-1-5);
\chainin (m-1-6);}
{ [start chain] \chainin (m-2-2);
\chainin (m-2-3);
{ [start branch=A] \chainin (m-1-3);}
\chainin (m-2-6);}
\end{tikzpicture}
\end{document}
The bottom timeline is still giving me issues. Also, I am not sure how to get the second upwards arrow. Thanks for your help.


tikzpackage: arrow between (x,y) [initial and final] :command:\draw[->] (x_init,y_init)--(x_fin,y_fin);symbol or phrase on point (x1,y1)\node at (x1,y1) {MySym};simple line like arrow but\drawinstead of\draw[->]– koleygr Dec 16 '17 at 11:08