Plot time-series data using Ruby Gnuplot

ruby_gnuplot_time_series.rb

require "gnuplot"

data=<<EOS
2016-07-19T23:47:53.432Z 33.2
2016-07-19T23:41:59.558Z 33.1
2016-07-19T23:36:06.183Z 32.9
2016-07-19T23:30:09.101Z 32.7
2016-07-19T23:24:15.936Z 32.6
2016-07-19T23:18:19.082Z 32.4
2016-07-19T23:12:20.944Z 32.4
2016-07-19T23:06:28.191Z 32.3
2016-07-19T23:00:35.459Z 31.6
2016-07-19T22:54:33.798Z 31.2
2016-07-19T22:48:31.436Z 30.7
2016-07-19T22:42:27.744Z 30.1
2016-07-19T22:36:30.776Z 29.7
2016-07-19T22:30:32.814Z 29.4
2016-07-19T22:24:38.774Z 28.8
2016-07-19T22:18:38.911Z 28.5
2016-07-19T22:12:45.805Z 28.2
2016-07-19T22:06:39.124Z 27.7
2016-07-19T22:00:39.920Z 27.1
2016-07-19T21:54:42.007Z 26.5
EOS

x = []
y = []
data.lines(){|line|
	a=line.split()
	x << a[0]
	y << a[1]
}

Gnuplot.open() do |gp|
    Gnuplot::Plot.new( gp ) do |plot|
    	plot.ylabel 'Temperature degree'
    	plot.xlabel "Time (starting at #{x[0]})"
    	plot.timefmt "'%Y-%m-%dT%H:%M:%SZ'"
    	plot.xdata "time"
    	plot.format "x '%H:%M'"
    	plot.style "data lines"
    	plot.set 'terminal postscript color eps enhanced font "Helvetica,13" size 16cm,8cm'
    	plot.set "output 'temperature-pcb.ps'"
    	plot.data << Gnuplot::DataSet.new( [x, y] ) do |ds|
    		ds.with = "linespoints"
    		ds.linecolor = "black"
    		ds.linewidth = "3"
    		ds.notitle
    		ds.using = "1:2"
    	end
    end
end

`ps2pdf temperature-pcb.ps`

temperature-pcb.png