Tikz: Better way to draw this simple diagram

Question

I want to draw something like this diagram in TikZ. My code is:

\documentclass[a4paper]{standalone}
\usepackage{tikz}
\usetikzlibrary{positioning}
\begin{document}    
\begin{tikzpicture}

    \node (wrijving)                           {wrijving};
    \node (lading)   [right=of wrijving]       {(onzichtbare) lading};
    \node (elkracht) [below=of lading]         {elektrische kracht};
    \node (afst)     [below left=of elkracht]  {afstoten};
    \node (aantr)    [below right=of elkracht] {aantrekken};

    \path (wrijving) edge[->] (lading)
          (lading)   edge[->] (elkracht)
          (elkracht) edge[-] (afst)
                     edge[-] (aantr);
\end{tikzpicture}
\end{document}

Which gives this:

Probably there's a better way to draw this, but I don't know how.

I also want "afstoten" and "aantrekken" to be closer. I know you can specify a value to below and left, but is is possible to have a branch with normal length, and just rotate it x deg?

Answer 1

Since it's a tree, here's a possibility using the forest package; the code is considerably shorter now and you have the desired control over the separation of the two lower elements using, for exmaple, the calign options (see lines commented out in my example code):

\documentclass{article}
\usepackage{forest}

\begin{document}

\begin{forest}
for tree={edge={->},
%calign=fixed edge angles,
%calign primary angle=-40,calign secondary angle=40
}
[wrijving,grow=0
  [(onzichtbare) lading
    [elektrische kracht    
      [afstoten]
      [aantrekken]
    ]
  ]    
]
\end{forest}

\end{document}

Answer 2

This does not yet adjust the positioning but is more concise:

\documentclass[tikz,border=10pt]{standalone}
\usetikzlibrary{chains,scopes}
\begin{document}
  \begin{tikzpicture}[start chain=main going right, every on chain/.append style={join}, every join/.append style={->}]
    \node [on chain] (wrijving) {wrijving};
    \node [on chain] (lading) {(onzichtbare) lading};
    \node [on chain=main going below] (elkracht) {elektrische kracht};
    {[start branch=split going below left]
      \node [on chain] (afst) {afstoten};}
    \node [on chain=main going below right] (aantr) {aantrekken};
\end{tikzpicture}
\end{document}

EDIT

To alter the compactness of the diagram when it branches, you can specify a more detailed direction for the chain. For example, using the calc library:

\documentclass[tikz,border=10pt]{standalone}
\usetikzlibrary{chains,scopes,calc}
\begin{document}
  \begin{tikzpicture}[start chain=main going right, every on chain/.append style={join}, every join/.append style={->}]
    \node [on chain] (wrijving) {wrijving};
    \node [on chain] (lading) {(onzichtbare) lading};
    \node [on chain=main going below] (elkracht) {elektrische kracht};
    \node [on chain={main placed {at=($(\tikzchainprevious.south)+(-50:1.5)$)}}] (aantr) {aantrekken};
    {[start chain=split]
      \chainin (elkracht);
      \node [on chain=placed {at=($(\tikzchainprevious.south)+(-130:1.5)$)}] (afst) {afstoten};}
\end{tikzpicture}
\end{document}

Note that I'm a big fan of forest and, if your diagrams are really trees, it is great. If not - that is, if they change direction many times and do not necessarily have single roots - then forest is still an option, but chains may be easier for simple cases, where programmatic power is not a significant consideration.

Answer 3

I present an alternative, more concise solution using the tikz-cd package that was made for commutative diagrams and has (in my opinion) very clear and simple syntax. With a bit of naive trickery, the spacing is also easily adjusted to yield whatever one likes:

\documentclass{article}
\usepackage{tikz-cd}
\begin{document}

\begin{tikzcd}
    \mathrm{wrijving} \arrow[rr]& &[-2cm] \mathrm{(onzichtbare)\ lading} \arrow[d] &[-2cm]\\
    & & \mathrm{elektrische\ kracht}\arrow[dl, no head]\arrow[dr, no head]\\
    & \mathrm{afstoten} & & \mathrm{aantrekken}
\end{tikzcd}

\end{document}

which produces the following: