<rrd_graph_def>
  <options>
    <vertical_label>Degrees C</vertical_label>
  </options>
  <datasources>
    <def>
      <name>inTemp</name>
      <rrd>${rrdFile}</rrd>
      <source>inTemp</source>
      <cf>AVERAGE</cf>
    </def>
    <cdef>
      <name>inTempC</name>
      <rpn>inTemp,32,-,9,/,5,*</rpn>
    </cdef>
    <def>
      <name>outTemp</name>
      <rrd>${rrdFile}</rrd>
      <source>outTemp</source>
      <cf>AVERAGE</cf>
    </def>
    <cdef>
      <name>outTempC</name>
      <rpn>outTemp,32,-,9,/,5,*</rpn>
    </cdef>
  </datasources>
  <graph>
    <line>
      <datasource>inTempC</datasource>
      <color>#FF0000</color>
      <legend>Inside Temperature</legend>
    </line>
    <line>
      <datasource>outTempC</datasource>
      <color>#0000FF</color>
      <legend>Outside Temperature</legend>
    </line>
  </graph>
</rrd_graph_def>