title: Inversion with ordinal scale
body: <p>Is there any way to find inversion of ordinal scale? </p>
  
  <p>I am using string value on x axis which is using ordinal scale and i on mouse move i want to find inversion with x axis to find which string is there at mouse position?</p>
  
  <p>Is there any way to find this?</p>
  
  <pre><code>var barLabels = dataset.map(function(datum) {
      return datum.image;
  });
  console.log(barLabels);
  var imageScale = d3.scale.ordinal()
          .domain(barLabels)
          .rangeRoundBands([0, w], 0.1);
  // divides bands equally among total width, with 10% spacing.
  console.log("imageScale....................");
  console.log(imageScale.domain());
  
   .
   .
  var xPos = d3.mouse(this)[0];
  xScale.invert(xPos);
  </code></pre>