From: Phlip <phlip2005@...>
Date: 2009-04-23T06:40:11+09:00
Subject: Re: gnuplot timeseries

> # causes error               plot.xrange
> "[\"2009-01-01T00:00:00+00:00\":\"2009-01-01T23:59:00+00:00\"]"

I'm not sure where the +00:00 comes from.

This post...

  http://www.oreillynet.com/ruby/blog/2008/03/cruisecontrol_charts.html

...shows how to format the time and build a range:

def timefmt;  '%Y/%d/%m-%H:%M';  end

def fetch_codelines(stat, fields)
  return stat.values_at(*fields).map{|values| values['codelines'] }.sum
end

def ftime(timestamp)
  Time.at(timestamp).strftime(timefmt)
end
...
plot.xrange "['#{ ftime(mini) }':'#{ ftime(maxi) }']"

I admit the documentation on that technique, in both Gnuplot.rb and gnuplot, 
are very scarce!