title: Gnuplot date/time in x axis
body: <p>I have a quick question regarding dates and times in x-axis in GNUPLOT. I'll let the code do the talking:</p>
  
  <p>This is my data:</p>
  
  <pre><code>#Time   Data in Data out
  "2013-07-22 15:59:00"   6286    3730
  "2013-07-22 15:58:00"   10695   14589
  "2013-07-22 15:57:00"   17868   26464
  "2013-07-22 15:56:00"   18880   34012
  "2013-07-22 15:55:00"   19206   41192
  "2013-07-22 15:54:00"   20365   43218
  "2013-07-22 15:53:00"   18459   39298
  "2013-07-22 15:52:00"   3420    4686
  "2013-07-22 15:51:00"   3256    4942
  </code></pre>
  
  <p>And this is the code that is generating the graph:</p>
  
  <pre><code>gnuplot&gt; set title "Data usage over the last 24 hours"
  gnuplot&gt; unset multiplot
  gnuplot&gt; set xdata time
  gnuplot&gt; set style data lines  
  gnuplot&gt; set term png
  Terminal type set to 'png'
  Options are 'nocrop font "arial,12" fontscale 1.0 size 640,480 '
  gnuplot&gt; set timefmt "%Y-%m-%d %H:%M:%S"
  gnuplot&gt; set format x "%m-%d\n%H:%M"
  gnuplot&gt; set xlabel "Time"
  gnuplot&gt; set ylabel "Traffic" 
  gnuplot&gt; set autoscale y  
  gnuplot&gt; set xrange ["2013-07-21 16:00":"2013-07-22 16:00"]
  gnuplot&gt; set output "datausage.png"
  gnuplot&gt; plot "C:\\Users\\blah\\Desktop\\plot.tmp" using 1:2 t "inbound" w lines, "C:\\Users\\blah\\Desktop\\plot.tmp" u 1:3 t "outbound" w lines
                                                                                                                                                                   ^
           all points y value undefined!
  </code></pre>
  
  <p>Is the problem the space in between <code>date</code> and <code>time</code> in the x-axis? If not, what do you think could be the problem?</p>