/**
	*  @desc 根据两点间的经纬度计算距离
	*  @param float $lat 纬度值
	*  @param float $lng 经度值
	*/
	function getDistance($lat1, $lng1, $lat2, $lng2){
		$earthRadius = 6371000; //近似地球半径 单位 米
		 /*
		   Convert these degrees to radians
		   to work with the formula
		 */

		$lat1 = ($lat1 * pi() ) / 180;
		$lng1 = ($lng1 * pi() ) / 180;

		$lat2 = ($lat2 * pi() ) / 180;
		$lng2 = ($lng2 * pi() ) / 180;


		$calcLongitude = $lng2 - $lng1;
		$calcLatitude = $lat2 - $lat1;
		$stepOne = pow(sin($calcLatitude / 2), 2) + cos($lat1) * cos($lat2) * pow(sin($calcLongitude / 2), 2);  $stepTwo = 2 * asin(min(1, sqrt($stepOne)));
		$calculatedDistance = $earthRadius * $stepTwo;
		
		$distance=$calculatedDistance/1000;
		if($distance<10){
			$rs=round($distance,2);
		}else if($distance > 1000){
			$rs='1000';
		}else{
			$rs=round($distance);
		}
		return $rs.'km';
	}