Decision Tree with Labels on Both Sides of Line

Question

I am trying to generate a decision tree similar to this scanned example:

Notice that some branches have text on the top as well as the bottom. I have not figured out how to do this. I can get text on the top or bottom, but not both.

I am enclosing a partial solution. I try to Add "Outbreak" as the top label and "0.060" as the bottom label, but it causes the first label to disappear.

   \documentclass{beamer}

\usepackage{tikz}
\usetikzlibrary{trees,shapes,snakes}
\usepackage{forest}


\tikzset{
    decision/.style={rectangle, minimum height=10pt, minimum width=10pt, draw=black, fill=black!30!white, thick, inner sep=0pt},
    chance/.style={circle, minimum width=10pt, draw=black, fill=black!30!white, thick, inner sep=0pt},
    leaf-chance/.style={isosceles triangle, minimum width=10pt, draw=black, thick, fill=white, inner sep=0pt, shape border rotate=180, outer sep=-\pgflinewidth}
  }

\newsavebox\notgood
\sbox\notgood{\textbardbl}
\forestset{
  declare toks={optimality}{},
  sub optimal/.style={
    optimality={
      node [midway, sloped] {\usebox\notgood}
    }
  }
}

\begin{document}


\begin{frame}[fragile]

\scalebox{0.85}{
 \begin{forest}
   %my label/.style={
   %   edge label={node[auto, sloped,pos=.75,anchor=south]{#1}}
   % },
   my label/.style={
     edge label={node[midway,above,font=\scriptsize,text width=1.5cm,align=center]{#1}}
   },
   my below/.style={
     edge label={node[midway,below,font=\scriptsize,text width=1.5cm,align=center]{#1}}
     },
    for tree={
      grow=0,
      child anchor=west,
      anchor=west,
      text ragged,
      inner sep=1mm,
      edge={thick, draw=blue},
      l sep+=30mm,
      s sep+=5mm,
      if n children=0{
        before typesetting nodes={
          label/.wrap pgfmath arg={right:#1}{content()},
          content={},
          leaf-chance,
        },
      }{},
      edge path={
        \noexpand\path[\forestoption{edge}]
       (!u.parent anchor) -- ([xshift=-22.5mm].child anchor)\forestove{optimality} --  (.child anchor)\forestoption{edge label};
  },
    }
    [,decision
      [0.8351,chance,my label=Insure]
      [,chance,my label=Don't Insure, sub optimal      
        [0.8394,chance,my label=No outbreak
        ]
        [,chance,my label=Outbreak, my below=0.060
          [0.8334,chance,my label=Bans only
          ]
          [0.6663,chance,my label=Slaughter
          ]
        ]
      ]
    ]
\end{forest}
}

\end{frame}
\end{document}

I found this previous answer helpful in switching between above/below, but doesn't show how to get both: https://tex.stackexchange.com/a/177254/80455

Also, this is the same example as Adding Short Lines Across Decision Tree Branch (but a different question).

Answer 1

edge label will override any previous value for any particular node. So the first label disappears. But we can use the same method as I used for the sub optimal style i.e. declare another option, just like edge label and then add it to the redefinition of edge path.

\documentclass{beamer}

\usepackage{etex,forest}
\usetikzlibrary{shapes,snakes}


\tikzset{
    decision/.style={rectangle, minimum height=10pt, minimum width=10pt, draw=black, fill=black!30!white, thick, inner sep=0pt},
    chance/.style={circle, minimum width=10pt, draw=black, fill=black!30!white, thick, inner sep=0pt},
    leaf-chance/.style={isosceles triangle, minimum width=10pt, draw=black, thick, fill=white, inner sep=0pt, shape border rotate=180, outer sep=-\pgflinewidth}
  }

\newsavebox\notgood
\sbox\notgood{\textbardbl}
\forestset{
  declare toks={optimality}{},
  sub optimal/.style={
    optimality={
      node [midway, sloped] {\usebox\notgood}
    }
  },
  declare toks={edge label below}{},
}

\begin{document}


\begin{frame}[fragile]
\scalebox{0.85}{%
 \begin{forest}
   my label/.style={
     edge label={node[midway,above,font=\scriptsize,text width=1.5cm,align=center]{#1}}
   },
  my below/.style={
    edge label below={node[midway,below,font=\scriptsize,text width=1.5cm,align=center]{#1}}
  },
    for tree={
      grow=0,
      child anchor=west,
      anchor=west,
      text ragged,
      inner sep=1mm,
      edge={thick, draw=blue},
      l sep+=30mm,
      s sep+=5mm,
      if n children=0{
        before typesetting nodes={
          label/.wrap pgfmath arg={right:#1}{content()},
          content={},
          leaf-chance,
        },
      }{},
      edge path={
        \noexpand\path[\forestoption{edge}]
        (!u.parent anchor) -- ([xshift=-22.5mm].child anchor)\forestove{optimality} --  (.child anchor)\forestoption{edge label below}\forestoption{edge label};
  },
    }
    [,decision
      [0.8351,chance,my label=Insure]
      [,chance,my label=Don't Insure, sub optimal
        [0.8394,chance,my label=No outbreak
        ]
        [,chance,my label=Outbreak, my below=0.060
          [0.8334,chance,my label=Bans only
          ]
          [0.6663,chance,my label=Slaughter
          ]
        ]
      ]
    ]
\end{forest}%
}%
\end{frame}
\end{document}

To avoid the crowding, either allow longer labels (increase or remove text width) or increase the value of s sep.

Removing the restriction on text width:

   my label/.style={
     edge label={node[midway,above,font=\scriptsize,align=center]{#1}}
   },
  my below/.style={
    edge label below={node[midway,below,font=\scriptsize,align=center]{#1}}
  },

Increasing s sep:

  s sep+=7.5mm,

Answer 2

This is a bit of a "hack", but you can simply set an extra label without the above or below keys. Then using \\ when you want to switch to the "other line", they will show one above, one below.

So basically, you'll have:

• my above
• my below
• my label (both)

As far as you've showed, this will work. If there is some situation where this behaviour breaks, please specify it.

Output

Code

\documentclass{beamer}   
\usepackage{tikz}
\usetikzlibrary{trees,shapes,snakes}
\usepackage{forest}


\tikzset{
    decision/.style={rectangle, minimum height=10pt, minimum width=10pt, draw=black, fill=black!30!white, thick, inner sep=0pt},
    chance/.style={circle, minimum width=10pt, draw=black, fill=black!30!white, thick, inner sep=0pt},
    leaf-chance/.style={isosceles triangle, minimum width=10pt, draw=black, thick, fill=white, inner sep=0pt, shape border rotate=180, outer sep=-\pgflinewidth}
  }

\newsavebox\notgood
\sbox\notgood{\textbardbl}
\forestset{
  declare toks={optimality}{},
  sub optimal/.style={
    optimality={
      node [midway, sloped] {\usebox\notgood}
    }
  }
}

\begin{document}


\begin{frame}[fragile]

\scalebox{0.85}{
 \begin{forest}
    my above/.style={
        edge label={node[midway,above,font=\scriptsize,align=center]{#1}}
    },
    my below/.style={
        edge label={node[midway,below,font=\scriptsize,align=center]{#1}}
    },
    my label/.style={
        edge label={node[midway,font=\scriptsize,align=center]{#1}}
    },
    for tree={
      grow=0,
      child anchor=west,
      anchor=west,
      text ragged,
      inner sep=1mm,
      edge={thick, draw=blue},
      l sep+=30mm,
      s sep+=5mm,
      if n children=0{
        before typesetting nodes={
          label/.wrap pgfmath arg={right:#1}{content()},
          content={},
          leaf-chance,
        },
      }{},
      edge path={
        \noexpand\path[\forestoption{edge}]
       (!u.parent anchor) -- ([xshift=-22.5mm].child anchor)\forestove{optimality} --  (.child anchor)\forestoption{edge label};
  },
    }
    [,decision
      [0.8351,chance,my above=Insure]
      [,chance,my below=Don't Insure, sub optimal      
        [0.8394,chance,my above=No outbreak
        ]
        [,chance,my label=Outbreak\\0.060
          [0.8334,chance,my above=Bans only
          ]
          [0.6663,chance,my below=Slaughter
          ]
        ]
      ]
    ]
\end{forest}
}
\end{frame}
\end{document}