public function areaMapToJson(){
        $returnValue = null;

        // Get the stored area mapping
        $mapping = $this->getMapping('area');

        if(count($mapping)){
            $returnValue = Array();
            $returnValue['identifier'] = $this->getIdentifier();
            $returnValue['defaultValue'] = $this->mappingDefaultValue;
            if($this->hasAttribute('areaMapping')){
                $returnValue = array_merge($returnValue, $this->getAttributeValue('areaMapping'));
            }
            $mappingValue = Array();

            // If a mapping has been defined
            if(!empty($mapping)){
                foreach($mapping as $mapKey => $mappedValue){
                    $areaMapEntryJSON = Array();
                    $areaMapEntryJSON['value'] = (float) $mappedValue["mappedValue"];
                    $areaMapEntryJSON['key'] = taoQTI_models_classes_Matching_VariableFactory::createJSONShapeFromQTIData($mappedValue);
                    array_push($mappingValue, (object) $areaMapEntryJSON);
                }
                $returnValue['value'] = $mappingValue;
            }

            $returnValue = (object) $returnValue;
        }

        return $returnValue;
    }