title: What would be the ideal JSON format for this specific XML
body: <p>Given the following XML example:</p>
  
  <pre><code>&lt;Meters&gt;
    &lt;Meter&gt;
      &lt;Meter_ID&gt;213&lt;/Meter_ID&gt;
      &lt;Reading1&gt;74.00000&lt;/Reading1&gt;
      &lt;DateTime1&gt;10/05/2011 09:00:18&lt;/DateTime1&gt;
      &lt;Reading2&gt;73.00000&lt;/Reading2&gt;
      &lt;DateTime2&gt;10/05/2011 09:15:18&lt;/DateTime2&gt;
      &lt;Reading3&gt;70.00000&lt;/Reading3&gt;
      &lt;DateTime3&gt;10/05/2011 09:30:18&lt;/DateTime3&gt;
    &lt;/Meter&gt;
    &lt;Meter&gt;
      &lt;Meter_ID&gt;69&lt;/Meter_ID&gt;
      &lt;Reading1&gt;146.00000&lt;/Reading1&gt;
      &lt;DateTime1&gt;10/05/2011 09:00:18&lt;/DateTime1&gt;
      &lt;Reading2&gt;167.00000&lt;/Reading2&gt;
      &lt;DateTime2&gt;10/05/2011 09:15:18&lt;/DateTime2&gt;
      &lt;Reading3&gt;173.00000&lt;/Reading3&gt;
      &lt;DateTime3&gt;10/05/2011 09:30:18&lt;/DateTime3&gt;
    &lt;/Meter&gt;
  &lt;/Meters&gt;
  </code></pre>
  
  <p>What would be the most compact JSON format, given that the end result is - for each <code>Meter_ID</code> - to get the 3 <code>ReadingN</code> and <code>DateTimeN</code> pairs?</p>