ParkListing.php

<?php

class ParkListing extends Location {

	/**
	 * @param GeocodedLocation $location
	 * @return DataList
	 */
	public static function get_by_geo(GeocodedLocation $location) {
		$query = new SQLQuery();
		$query->setFrom('Location');
		$query->addLeftJoin('ParkListing', 'Location.ID = ParkListing.ID');
		$query->selectField(
			'(((acos(sin((' . $location->Lat . ' *pi()/180))*sin((`GMapLat`*pi()/180))+cos(('
			. $location->Lat . '*pi()/180))*cos((`GMapLat`*pi()/180))*cos(((' . $location->Lon
			. '-`GMapLon`)*pi()/180))))*180/pi())*60*1.1515) as Distance'
		);
		$query->setHaving('Distance < 50');
		$query->setOrderBy('Distance', 'asc');
		$array = $query->execute();

		$results = array();

		foreach($array as $row) {
			$results[] = self::create($row);
		}

		return new ArrayList($results);
	}

}