<?php
/**

  • @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

*/
function getDistance($lat1, $lng1, $lat2, $lng2){

$earthRadius = 6367000; //approximate radius of earth in meters$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);return $calculatedDistance;

}

//循环调用然后依次返回距离
/**
*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5千米
*@return array 正方形的四个点的经纬度坐标
*/
function returnSquarePoint($lng, $lat,$distance = 5)
{

$dlng =  2 * asin(sin($distance / (2 * 6371)) / cos(deg2rad($lat)));$dlng = rad2deg($dlng);$dlat = $distance/6371;//地球半径，平均半径为6371km$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));

}

//计算附近五公里的经纬度范围
//根据这个范围到数据库查询满足条件的店面
/**

  • 获取一定范围内的地点

*/
function getSiteData($lng,$lat,$userType)
{

//使用此函数计算得到结果后，带入sql查询。$squares = $this->returnSquarePoint($lng, $lat);if($squares['left-top']['lng'] > $squares['right-bottom']['lng']){    $lngMin = $squares['right-bottom']['lng'];    $lngMax = $squares['left-top']['lng'];}else{    $lngMin = $squares['left-bottom']['lng'];    $lngMax = $squares['right-top']['lng'];}if($squares['left-top']['lat'] > $squares['right-bottom']['lat']){    $latMin = $squares['right-bottom']['lat'];    $latMax = $squares['left-top']['lat'];}else{    $latMin = $squares['left-top']['lat'];    $latMax = $squares['right-bottom']['lat'];}$where = "lng<>0 and lng>=$lngMin and lng<=$lngMax and lat>=$latMin and lat<=$latMax and status=1";if($userType){    $where .= " AND type = 2";}else{    $where .= " AND type = 1";}$site_info = M('Site')->field('id,address,lat,lng')->where($where)->select();return $site_info;

}