function temperaturesJSON($fromDate, $toDate)
	{
		global $SONDES;
		
		// Let us export at the json format
		$cmd = "rrdtool xport --start ".$fromDate." --end ".$toDate." --json ";
		
		$i = 1;
        foreach ($SONDES as $name => $Sonde)
		{
			$cmd .= _temperaturesJSON($i, $name);
			$i++;
		}
		$cmd .= _temperaturesJSON($i, "out");
		$val = shell_exec($cmd);
		
		// Let us repair the json, so it will effectively be a json
		$val = str_replace(' data:', ' "data":', $val);
		$val = str_replace(' about:', ' "about":', $val);
		$val = str_replace(' meta:', ' "meta":', $val);
		$val = str_replace(' start:', ' "start":', $val);
		$val = str_replace(' step:', ' "step":', $val);
		$val = str_replace(' end:', ' "end":', $val);
		$val = str_replace(' legend:', ' "legend":', $val);
		$val = str_replace("'", '"', $val);
		
		// Now let us convert to the json format for extjs
		$obj = json_decode($val);
		$startTime = $obj->meta->start;
		$step = $obj->meta->step;
		
		$currentTime = $startTime;
		
		$newObj = array( "data" => array() );
		
		foreach ($obj->data as $index => $array)
		{
			$newArray = array( "time" => $currentTime*1000 );
			
			foreach ($obj->meta->legend as $legendIndex => $legendName)
			{
				$newArray[$legendName] = $array[$legendIndex] != null ? $array[$legendIndex] : undefined;
			}
			
			$newObj['data'][] = $newArray;	
			
			$currentTime += $step;
		}
		// ok we can return it now
		$retVal = json_encode($newObj);
		return $retVal;
	}