/*
 * 经度纬度 转换成距离
 * $lat1 $lng1 是 数据的经度纬度
 * $lat2,$lng2 是获取定位的经度纬度
 */

function rad($d) {
	return $d * 3.1415926535898 / 180.0;
}

function getDistanceNone($lat1, $lng1, $lat2, $lng2) {
	$EARTH_RADIUS = 6378.137;
	$radLat1 = rad($lat1);
	//echo $radLat1;
	$radLat2 = rad($lat2);
	$a = $radLat1 - $radLat2;
	$b = rad($lng1) - rad($lng2);
	$s = 2 * asin(sqrt(pow(sin($a / 2), 2) + cos($radLat1) * cos($radLat2) * pow(sin($b / 2), 2)));
	$s = $s * $EARTH_RADIUS;
	$s = round($s * 10000);
	return $s;
}

function getDistance($lat1, $lng1, $lat2, $lng2) {
	$s = getDistanceNone($lat1, $lng1, $lat2, $lng2);
	$s = $s / 10000;
	if ($s < 1) {
		$s = round($s * 1000);
		$s.='m';
	} else {
		$s = round($s, 2);
		$s.='km';
	}
	return $s;
}

function getDistanceCN($lat1, $lng1, $lat2, $lng2) {
	$s = getDistanceNone($lat1, $lng1, $lat2, $lng2);
	$s = $s / 10000;
	if ($s < 1) {
		$s = round($s * 1000);
		$s.='米';
	} else {
		$s = round($s, 2);
		$s.='千米';
	}
	return $s;
}
//ENd 经纬度转换