Re: Generating boxplot (candlestick) diagrams (babel or org-plot)

[Eric Schulte <eric.schulte@gmx.com>]

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Karl Voit <devnull@Karl-Voit.at> writes:

> Hi!
>
> I'm new to babel/gnuplot/org-plot and want to generate classic
> Boxplot[1] diagrams.
>
> My tests failed so far:
>
> #+TBLNAME: mydata
> #+PLOT: title:"Boxplots of mydata" with:candlesticks
> | A | B |
> |---+---|
> | 5 | 5 |
> | 5 | 6 |
> | 4 | 5 |
> | 5 | 6 |
> | 2 | 4 |
> | 2 | 5 |
>
> ... with «org-plot/gnuplot» results in:
> #+begin_verse
> gnuplot-mode 0.6.0 (gnuplot 4.4) -- report bugs with "C-c C-u"
> Starting gnuplot plotting program...Done
>
> #+end_verse
>
> ... with nothing else.
>
>
> #+begin_src gnuplot  :var data=mydata :file output.png
> set title "Plot Test"
>
> plot data using 1:2 with candlestick
> #+end_src
>
> ... results in empty output.png file.
>

In more complex examples like these I would recommend using a gnuplot
code block rather than using Org-plot.  Gnuplot has an extremely
comprehensive built in help system, typing "help boxplot" at the gnuplot
REPL returns the following.

,----
| gnuplot> help boxplot
|  Boxplots are a common way to represent a statistical distribution of values.
|  Quartile boundaries are determined such that 1/4 of the points have a value
|  equal or less than the first quartile boundary, 1/2 of the points have a value
|  equal or less than the second quartile (median) value, etc.  A box is drawn
|  around the region between the first and third quartiles, with a horizontal line
|  at the median value.  Whiskers extend from the box to user-specified limits.
|  Points that lie outside these limits are drawn individually.
| 
|  Examples
| 
|      # Place a boxplot at x coordinate 1.0 representing the y values in column 5
|      plot 'data' using (1.0):5
| 
| ...
`----

Also see the help for "candlestick".  Using this information the
attached Org-mode file generates a candlestick plot using a Gnuplot code
block.


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#+Title: Box-Plots with Gnuplot
#+Options: ^:nil

#+name: sample
| x | box_min | whisker_min | whisker_high | box_high |
|---+---------+-------------+--------------+----------|
| 1 |       2 |           0 |            6 |        4 |
| 2 |       3 |           1 |            7 |        5 |
| 3 |       4 |           2 |            8 |        6 |
| 4 |       5 |           3 |            9 |        7 |
| 5 |       6 |           4 |           10 |        8 |
| 6 |       7 |           5 |           11 |        9 |

#+begin_src gnuplot :var data=sample :results silent
  set xrange [0:7]
  plot data using 1:2:3:4:5 with candlesticks
#+end_src

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Best,

>
>
> What is the problem here? At least the second method should end up
> in an error message or a file with content I guess.
>
>   1. http://en.wikipedia.org/wiki/Boxplot

-- 
Eric Schulte
http://cs.unm.edu/~eschulte/