php経緯度計算のいくつかの機能について(app地図クエリー)
1934 ワード
1.緯度による近隣情報の照会
2.緯度に基づいて2点間の距離を調べる
/**
*
*
*@param lng float
*@param lat float
*@param distance float , , 0.5
*@return array
*/
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']['lng']} and lng
2.緯度に基づいて2点間の距離を調べる
/**
* @desc
* @param float $lat
* @param float $lng
*/
private function getDistance($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);
}