php关于经纬度计算的一些功能（app地图查询）

1.根据经纬度 查询附近信息

/**
 *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
 */
private function returnSquarePoint($lng, $lat, $distance){

    $distance = $distance?$distance:5;
    $earthRadius = 6378;
    $dlng =  2 * asin(sin($distance / (2 * $earthRadius)) / cos(deg2rad($lat)));
    $dlng = rad2deg($dlng);
    $dlat = $distance/$earthRadius;
    $dlat = rad2deg($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)
    );
}
$info_sql = "select id,locateinfo,lat,lng from `lbs_info` where lat<>0 and lat>{$squares['right-bottom']['lat']} and lat<{$squares['left-top']['lat']} and lng>{$squares['left-top']['lng']} and lng<{$squares['right-bottom']['lng']} "; 

2.根据经纬度查询两点之间的距离

/** 
* @desc 根据两点间的经纬度计算距离 
* @param float $lat 纬度值 
* @param float $lng 经度值 
*/
private function getDistance($lat1, $lng1, $lat2, $lng2){ 
    $earthRadius = 6367; //approximate radius of earth in meters 
     
    $lat1 = ($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; 
     
    return round($calculatedDistance,2); 
}