title: Plotting with a time axis in Matlab using dateTick and dateNumbers
body: <p>I am making a script to plot burst signal events on a pesudo-waterfall.
  With x-axis being frequencyand y-axis being time I plot a line from
  [event-frequency event-startTimeStamp] to [event-frequency event-endTimeStamp]
  to represent each burst.</p>
  
  <p>I am using the following code:</p>
  
  <pre><code>tstart = datenum(0,0,0,0,0,0);
  tend = datenum(0,0,0,0,0,1);
  timeInterval=tend-tstart;
  xlim([0 10]);
  hold on;
  
  cla;
  timeAxis = linspace(tstart, tend, 100);
  set(gca,'YTick',timeAxis,'FontSize',6,'YDir','reverse');
  datetick('y','HH:MM::SS.FFF','keepticks');
  plot([1 1],[tstart tstart+timeInterval/4]);
  plot([2 2],[tstart+timeInterval/8 tstart+timeInterval/2]);
  tstart=tstart + timeInterval;
  tend=tend + timeInterval;
  </code></pre>
  
  <p>The paragraph from the cla can be repeated to plot 'signals' in later time increments of one second.  This works fine.
  If I change the first two lines to the following: edit: using this value cuz it's the timestamp of the first burst</p>
  
  <pre><code>tstart = datenum(2011,6,13,15,10,40.999);
  tend = tstart + datenum(0,0,0,0,0,1);
  </code></pre>
  
  <p>The plot looks horrible and the labels get messed up into a black mess.  I can't work out why it's happening.  Anybody know?
  (copy-pastable code if you wanna try it out)</p>
  
  <p>-Daniel</p>