public function getPlacementLocationsAction()
 {
     $wh_id = $this->_request->getParam('wh_id');
     $type = $this->_request->getParam('loctype');
     $locations = new Model_Locations();
     $result = $locations->getPlacementLocations($wh_id, $type);
     echo Zend_Json::encode($result);
 }