How can the plot symbol be specified in the ruby implementation of gnuplot?

Question

The default plot symbol for an x,y dataset is a red cross. Let's say I'd like it to be a filled, black square. How do I do that?

To be transparent about what I'm doing in this code example, I set up a plot using gnuplot at the (already-specified) output path. It's a png, with a specified size, font and fontsize. I fiddle a bit with the left margin and border thickness and give my axes some titles, but those are other aesthetics.

To generate black lines, I would uncomment that one commented line. How do I get, say, filled squares though? I cannot work it out from the gnuplot documentation at http://gnuplot.sourceforge.net/docs_4.6/gnuplot.pdf

  ::Gnuplot.open do |gp|
    ::Gnuplot::Plot.new(gp) do |plot|
      plot.terminal "png size 1800,600 font \"arial,20\""
      plot.lmargin "10"
      plot.output "#{star[:wrapped_rv_plot]}"
      plot.border "linewidth 2"
      plot.ylabel "Radial velocity (km/s)"
      plot.xlabel "Orbital Phase"

      x = ext_phase_rv.map { |point| point[0] }
      y = ext_phase_rv.map { |point| point[1] }

      plot.data << ::Gnuplot::DataSet.new([x, y]) do |ds|
        # ds.with = "lines lt rgb \"black\""
        ds.notitle
      end
    end
  end

score 1 · Accepted Answer · edited May 23 '17 at 10:32

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You get squared points with linetype 5, see e.g. Gnuplot line types. To plot with points, use with points :)

ds.with = "points"
ds.linecolor = "rgb 'blue' linetype 5"

edited May 23 '17 at 10:32

Community

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answered Apr 15 '14 at 08:20

Christoph

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That didn't quite do it, but it led me along the right track. Particularly with the reference to the test page. Thanks! – sjmurphy Apr 17 '14 at 01:27
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For me it works fine, of course I tested it before answering! The current version of the [ruby gnuplot gem](https://github.com/rdp/ruby_gnuplot/blob/master/lib/gnuplot.rb) even allows you to use `ds.linestyle` and define proper line styles. – Christoph Apr 18 '14 at 18:09

score 0 · Answer 2 · answered Apr 17 '14 at 01:28

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Replacing the commented line with the code below will produce black squares. Please see Christoph's answer for a link to more 'pt' (point type) examples.

ds.with = "points lc rgb 'black' pt 5"

answered Apr 17 '14 at 01:28

sjmurphy

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How can the plot symbol be specified in the ruby implementation of gnuplot?

2 Answers2