计算某个经纬度的周围某段距离的正方形的四个点

/**
 * 计算某个经纬度的周围某段距离的正方形的四个点
 *
 * @param
 *            lng float 经度
 * @param
 *            lat float 纬度
 * @param
 *            distance float 该点所在圆的半径，该圆与此正方形内切，默认值为0.5千米
 * @return array 正方形的四个点的经纬度坐标
 */
function returnSquarePoint($lng, $lat, $distance = 0.5)
{
    // defined(EARTH_RADIUS) || define(EARTH_RADIUS, 6371);//地球半径，平均半径为6371km
    $dlng = 2 * asin(sin($distance / (2 * 6371)) / cos(deg2rad($lat)));
    $dlng = rad2deg($dlng);
    
    $dlat = $distance / 6371;
    $dlat = rad2deg($dlat);
    
    return array(
        'left-top' => array(
            'lat' => $lat + $dlat,
            'lng' => $lng - $dlng
        ),
        'right-top' => array(
            'lat' => $lat + $dlat,
            'lng' => $lng + $dlng
        ),
        'left-bottom' => array(
            'lat' => $lat - $dlat,
            'lng' => $lng - $dlng
        ),
        'right-bottom' => array(
            'lat' => $lat - $dlat,
            'lng' => $lng + $dlng
        )
    );
}

 获取附近：

$sql = "select * from `network_office_building` where province=? and city=? and district=? and location_lng<>0 and location_lat>{$squares['right-bottom']['lat']} and location_lat<{$squares['left-top']['lat']} and location_lng>{$squares['left-top']['lng']} and location_lng<{$squares['right-bottom']['lng']} ";
$results = DB::connection('net')->select($sql, [
            $row->province,
            $row->city,
            $row->district
        ]);        

http://blog.51cto.com/imguowei/1952035