Data Visualization with GNU Emacs

 


 

GNU Emacs can be used for quick data visualization in combination with Gnuplot. When you have some data and you want to visualize what the correlation looks like, this command comes in handy. No need for any setup - no data file and no Gnuplot script.

The command below uses some sensible defaults for trivial cases.

  • If the first line contains string label, the same is used as a key label for the value and/or axes' names as appropriate.
  • If there's a single column of data, it is used as Y value.
  • If there's more than one column, first column is used as X value and other columns are plotted along Y-axis.
  • Takes care of comma or whitespace separator.

Note: The latest version of the code is available at the end of the post.

Options available in latest version

 

- Install gnuplot executable and gnuplot Elisp package.

- Evaluate the defun (C-M-x).

- Select a data range using rectangle command copy-rectangle-as-kill (C-x r M-w).

- Run M-x  gnuplot-rectangle. This opens the graph in a new window for easier interaction. Use C-q to exit.

- Run C-u M-x  gnuplot-rectangle to specify title and style (added in updated version).

(defun gnuplot-rectangle (&optional title style)
  (interactive)
  (let* ((name (make-temp-file "plot"))
         (buf (find-file name))
         xlabel ylabel cols header n)
    (with-current-buffer buf
      (setq cols (split-string (car killed-rectangle)))
      (when (string-match-p "^[a-zA-Z]" (car cols))
        (setq header cols)
        (pop killed-rectangle))
      (setq n (length header))
      (pcase n
        (1 (setq ylabel (nth 1 header)))
        (2 (setq xlabel (nth 0 header)
                 ylabel (nth 1 header)))
        (_ (setq xlabel (nth 0 header))))
      (yank-rectangle)
      (save-buffer))

    (setq style (or style "line"))
    (with-temp-buffer
      (insert "set title  '" (or title "Title") "'\n")
      (insert "set xlabel '" (or xlabel "x-axis") "'\n")
      (insert "set ylabel '" (or ylabel "y-axis") "'\n")
      (insert "plot '" name "'")
      (setq n (length cols))
      (dotimes (i (1- n))
        (if (> n 1) (insert " using 1:" (number-to-string (+ i 2))))
        (if (< i n) (insert " with " style))
        (if (> n 2)
            (insert " title '" (nth (+ i 1) header) "'")
          (insert " notitle"))
        (if (> i 0) (insert ",")))
      (if (= 1 n) (insert " using 1 with " style " notitle"))
      (newline)
      (gnuplot-mode)
      (gnuplot-send-buffer-to-gnuplot))

    ;; Cleanup
    (kill-buffer buf)
    ;; (delete-file name)
    )) 

 

Bar graph


Time series


Scatter plot


Pie chart


Live Preview

Use M-x gnuplot-preview to generate live preview of supported graph types.


Code

 

Comments

Post a Comment

Popular posts from this blog

GNU Emacs as a Comic Book Reader

Image
  Comics are available in digital format as a collection of images in a compressed ZIP or RAR file (.cbz or .cbr file extension respectively). These can be enjoyed in GNU Emacs with full access to image viewing capabilities using keybindings.   # Make sure you have unrar installed for CBR files # apt install unrar   (require 'arc2-mode)   (setq archive-summarize-files-fn 'archive-summarize-files-as-thumb)     Note: The archive-mode is capable of displaying the list of files in an archive; though it depends on external tools for extraction. For JPG and PNG, Emacs can resize the image without external convertor (ie. imagemagick). However, some menu options for image transformations in image-mode might not be available. Use the following patch for image-mode.el . @@ -460,16 +460,16 @@ image-mode-map       :help "Show image as hex"]      "--"      ["Fit to Window Height" image-transform-fit-to-...
Read more

HTML Renderer (Emacs)

Image
  Emacs: A non-intrusive browser An Elisp implementation of HTML rendering using SVG. The browser functionality is an extension of eww . For Javascript, you can use either NodeJS or QuickJS as a JS interpreter . Developer Note: The entry point is shr-render.   Table Colspan example Rowspan example Sample Table <html>   <body>     <table border="1">       <tr bgcolor="#9acd32">         <th style="text-align:left">Title</th>         <th style="text-align:left">Artist</th>       </tr>       <tr>         <td>Empire Burlesque</td>         <td>Bob Dylan</td>       </tr>     </table>   </body> </html...
Read more

Mozilla Readability in GNU Emacs

Image
  Output using Readability (left) and original eww (right)   Mozilla Readability is a standalone version of the readability library used for Firefox Reader View . A simple hack to eww can bring the same feature in GNU Emacs. ( Note: eww already has a readable mode. This is just an alternative. Updated the post to reflect the same.)   - Install NodeJS   - Install npm modules. npm install @mozilla/readability jsdom   - Create a file readability.js with following content. Note the file location. var { Readability } = require('@mozilla/readability'); var { JSDOM } = require('jsdom'); var fs = require("fs"); var str = fs.readFileSync(process.stdin.fd).toString(); var doc = new JSDOM(str); var reader = new Readability(doc.window.document); var article = reader.parse(); console.log(article.content);     - Modify the following function to use the file location noted above . Evaluate the function. (defun mozilla-readability (start end)   (shell-command-o...
Read more