[Tex/LaTex] Draw Image (Data flow)

diagrams

I am newbie in this TEX world and I would like to draw something like this:
alt text

But I don't know where to start.
I tried using: \usepackage{pstricks,pst-node,pst-tree}
but when I try to use it I got many errors, am I in the right way?

Best Answer

This is a solution with tikz that looks like your screenshot given above

\documentclass[]{article}

%load tikz
\usepackage{tikz}
%load additional library
\usetikzlibrary{positioning}

\begin{document}

%start tikzpicture,define a node style
\begin{tikzpicture}[mystyle/.style={draw,rectangle,fill=blue!30,thick,minimum
width=3cm,minimum height=1cm}]
%start to define nodes relative to each other
\node[mystyle] (A) {A};
\node[mystyle] (B) [below=of A] {B};
\node[mystyle] (C) [below=of B] {C}; 
\node[mystyle] (D) [below=of C] {D};

%second column with a bit of a distance
\node[mystyle,node distance=2cm] (E) [right=of A] {E};  
\node[mystyle,node distance=2cm] (F) [right=of B] {F};
\node[mystyle,node distance=2cm] (G) [right=of D] {G};       

\node[mystyle,node distance=2cm] (H) [right=of E] {H};  

%empty node for the gap in column 2 row 3
\node[minimum width =3cm,node distance=2cm] (J) [right=of C] {};  
\node[mystyle,node distance=2cm] (K) [right=of J] {K};       

%connect the nodes
\draw[->] (A) -- (B);
\draw[->] (B) -- (C);
\draw[->] (C) -- (D);
\draw[->] (G) -- (G);
\draw[->] (E) -- (F);
\draw[->] (F) -- (G);
\draw[->] (G) -| (K);
\draw[->] (K) -- (H);
\draw[->] (C) -- (K);

\end{tikzpicture}

\end{document}

alt text