title: D3 time and date histogram
body: <p>I'm attempting to make a histogram using primarily time and date data, provided in a json file (along with other info) in this format: 2014-03-01 00:18:00. I've looked at <a href="http://bl.ocks.org/mbostock/3048450" rel="nofollow">http://bl.ocks.org/mbostock/3048450</a> as an example, but I haven't managed to crack it. The key part seems to be this: </p>
  
  <pre><code>    var data = d3.layout.histogram()
          .bins(x.ticks(20))
          (dataset.timestamp);
  </code></pre>
  
  <p>When I view my code in the browser it gives "TypeError: data is undefined", and refers to d3.v3.js line 5878.</p>
  
  <p>Assuming I fix that error, the next place it may stumble is the axis formatting:</p>
  
  <pre><code>    var formatDate = d3.time.format("%y-%m-%d %h:%m:%s");
  
      var xAxis = d3.svg.axis()
          .scale(x)
          .orient("bottom")
          .tickFormat(formatDate);
  </code></pre>
  
  <p>Will the format syntax correspond correctly to my time and date format?</p>