实现原理先算出该点周围的矩形的四个点，然后使用经纬度去直接匹配数据库中的记录。
- //获取周围坐标
- public function returnSquarePoint($lng, $lat,$distance = 0.5){
- $earthRadius = 6378138;
- $dlng = 2 * asin(sin($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 + $dlng)
- );
- }
- //计算两个坐标的直线距离
-
- public function getDistance($lat1, $lng1, $lat2, $lng2){
- $earthRadius = 6378138; //近似地球半径米
- // 转换为弧度
- $lat1 = ($lat1 * pi()) / 180;
- $lng1 = ($lng1 * pi()) / 180;
- $lat2 = ($lat2 * pi()) / 180;
- $lng2 = ($lng2 * pi()) / 180;
- // 使用半正矢公式 用尺规来计算
- $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);
- }
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