Vertical histogram tikz

Question

How can I create a vertical histogram in Tikz?

I am creating a figure that looks like the one below, however its just a conceptual diagram, thus I do not need it to follow real data.

I already have a square with all needed inside but I want to be able to locate a histogram in the Y axis to the left. I though about creating a bunch of boxes, but I though there may be a better way.

Answer 1

Using pgfplots might be an option, horizontal bars can be made with xbar, vertical with ybar. Some key points:

• You just want the histogram, so hide axis hides axis lines, ticks, etc.
• scale only axis might on second thought be unnecessary. Without this option the specified width/height will include axis labels and ticklabels.
• You place the axis at the desired place with the at key, e.g. at={(5cm,0)}, which places the bottom left corner of the axis at (5cm,0).
• In order to ensure that there is no space between the bars, and that the full width of the bars are shown, the following steps are taken:
  1. Set the width/height of the axis to a specific length, e.g. height=5cm for the horizontal bars.
  2. The width of the bars themselves is the axis width/height divided by the number of bars. I have three bars in the example below, so I set bar width=5cm/3 for the horizontal bars.
  3. The y-coordinate is at the center of the bars, so to ensure that pgfplots extends the axis limits just enough, I add enlargelimits={abs=5cm/6}, which means that the axis limits will be extended half a bar width beyond the first/last point.

\documentclass[tikz, border=5mm]{standalone}
\usepackage{pgfplots}
\begin{document}
\begin{tikzpicture}
\draw (0,0) rectangle (4,5);

% histogram on right
\begin{axis}[
  at={(4cm,0)},
  xbar,
  enlargelimits={abs=5cm/6},
  scale only axis,
  hide axis,
  height=5cm,
  bar width=5cm/3]
\addplot coordinates {(3,0)(5,1)(2,2)};
\end{axis}

%histogram on top
\begin{axis}[
  at={(0,5cm)},
  ybar,
  enlargelimits={abs=4cm/6},
  scale only axis,
  hide axis,
  width=4cm,
  bar width=4cm/3]
\addplot coordinates {(0,1)(1,4)(2,2)};
\end{axis}
\end{tikzpicture}
\end{document}