title: How to write quarters on X-Axis labels in Telerik's RadChart?
body: <p>I am using the Telerik's RadChart control that displays some time-based data on a chart. Timestamp is the X-axis dimension.</p>
  
  <p>The control lets me set the label format for that axis, and that's the same format used by <code>DateTime.ToString()</code> method. For example:</p>
  
  <p><code>"yyyy-mm-dd"</code> would produce dates like <code>2011-11-18</code>.</p>
  
  <p>However, I'd like to categorize the data by the Quarters (I,II,III,IV). There is no such format specifier nor does the DateTime deals with Quarters. </p>
  
  <p>Is there any way to define the quarter (via format specifiers), or delegate the process of writing the label to a custom function (via some Telerik RadChart's settings)?</p>