Decision Tree with Tikz

Question

I am trying to draw a decision tree. I have gotten very close to the end result with this:

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{trees,shapes,snakes}
\begin{document}
\tikzstyle{level 1}=[level distance=1.5cm, sibling distance=2.5cm]
\tikzstyle{level 2}=[level distance=1cm, sibling distance=2cm]
\tikzstyle{level 3}=[level distance=1cm, sibling distance=1.5cm]
\tikzstyle{bag} = [rectangle, text width=4em, text centered, draw]
\tikzstyle{decision} = [rectangle, minimum height=8pt, minimum width=8pt, fill, inner sep=0pt]
\tikzstyle{choice} = [circle, minimum width=8pt, fill, inner sep=0pt]
\tikzstyle{end} = [regular polygon, regular polygon sides=3, minimum width=8pt, fill, inner sep=0pt]

\begin{tikzpicture}[grow=right,child anchor=west]
\tiny
\node[bag]{Decision}
child {
    node[decision]{}
    child {
        node[bag]{Option 1}
            child{
                node[choice]{}
                child {
                    node[bag]{Outcome 1}
                    child {
                        node[end]{}
                    }
                }
                child {
                    node[bag]{Outcome 2}
                    child {
                        node[end]{}
                    }
                }
            }
    }
    child {
        node[bag]{Option 2}
            child{
                node[choice]{}
                child {
                    node[bag]{Outcome 3}
                    child {
                        node[end]{}
                    }
                }
                child {
                    node[bag]{Outcome 4}
                    child {
                        node[end]{}
                    }
                }
            }
        }
    };
\end{tikzpicture}
\end{document}

The only issue I'm having is that I cannot find a way to rotate the last node (end), shaped as a triangle, as it should point towards its parent, not upwards. Any ideas?

Answer 1

You can rotate the end nodes by using the option shape border rotate=90 (unlike rotate=90, this will not shift the anchor point used by the tree, so the shape will be correctly aligned).

This will leave a small gap between the tip of the triangle and the edge of the tree. To avoid this, you can set outer sep=-\pgflinewidth, which will move the anchor slightly inside the shape, so the edge of the tree and the triangle overlap.