SimplePie_Item::get_latitude

	 * Compatible with the W3C WGS84 Basic Geo and GeoRSS specifications
	 *
	 * Uses `<geo:lat>` or `<georss:point>`
	 *
	 * @since 1.0
	 * @link http://www.w3.org/2003/01/geo/ W3C WGS84 Basic Geo
	 * @link http://www.georss.org/ GeoRSS
	 * @return string|null
	 */
	public function get_latitude()
	{
		if ($return = $this->get_item_tags(SIMPLEPIE_NAMESPACE_W3C_BASIC_GEO, 'lat'))
		{
			return (float) $return[0]['data'];
		}