/**
* Prepare the queries used for the pre processing
*
* @return self
*/
protected function prepareQueries()
{
$this->xAxisQuery = clone $this->baseQuery;
$this->xAxisQuery->distinct();
$this->xAxisQuery->setColumns(array($this->xAxisColumn));
$this->yAxisQuery = clone $this->baseQuery;
$this->yAxisQuery->distinct();
$this->yAxisQuery->setColumns(array($this->yAxisColumn));
return $this;
}
