geohash实现附近的工作室,php函数实现-tp5

 /********** geohash是一种地址编码，它能把二维的经纬度编码成一维的字符串。
* 得到编码
* $latitude //纬度
* $longitude //经度
* $precision //精密度, 默认是12
* @return string
*/
function encode_geohash($latitude, $longitude, $deep)
{
$BASE32 = '0123456789bcdefghjkmnpqrstuvwxyz';
$bits = array(16,8,4,2,1);
$lat = array(-90.0, 90.0);
$lon = array(-180.0, 180.0);

$bit = $ch = $i = 0;
$is_even = 1;
$i = 0;
$geohash = '';
while($i < $deep)
{
if ($is_even)
{
$mid = ($lon[0] + $lon[1]) / 2;
if($longitude > $mid)
{
$ch |= $bits[$bit];
$lon[0] = $mid;
}else{
$lon[1] = $mid;
}
} else{
$mid = ($lat[0] + $lat[1]) / 2;
if($latitude > $mid)
{
$ch |= $bits[$bit];
$lat[0] = $mid;
}else{
$lat[1] = $mid;
}
}

$is_even = !$is_even;
if ($bit < 4)
$bit++;
else {
$i++;
$geohash .= $BASE32[$ch];
$bit = 0;
$ch = 0;
}
}
return $geohash;
}

/******geohash解码
* @param $geohash
* @return array
*/
function decode_geohash($geohash)
{
$geohash = strtolower($geohash);
$BASE32 = '0123456789bcdefghjkmnpqrstuvwxyz';
$bits = array(16,8,4,2,1);
$lat = array(-90.0, 90.0);
$lon = array(-180.0, 180.0);
$hashlen = strlen($geohash);
$is_even = 1;

for($i = 0; $i < $hashlen; $i++ )
{
$of = strpos($BASE32,$geohash[$i]);
for ($j=0; $j<5; $j++) {
$mask = $bits[$j];
if ($is_even) {
$lon[!($of&$mask)] = ($lon[0] + $lon[1])/2;
} else {
$lat[!($of&$mask)] = ($lat[0] + $lat[1])/2;
}
$is_even = !$is_even;
}
}
$point = array( 0 => ($lat[0] + $lat[1]) / 2, 1 => ($lon[0] + $lon[1]) / 2);
return $point;
}
/**
* 计算两个经纬度距离
* @param $lat1 纬度
* @param $lng1 经度
* @param $lat2 纬度
* @param $lng2 经度
*/
function get_distance($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);
}

$latitude=$this->request->param('latitude',39.4);//纬度
$longitude=$this->request->param('longitude',116);//经度
if(!$longitude||!$latitude){
$this->error('位置参数不全');
}
$now_geohash=encode_geohash($latitude, $longitude, $deep=3);//当前位置的区域码,码位数越短范围越大，可以通过增大deep的值来缩小搜索范围
$list=Db::name('studio')->where('geohash','like',$now_geohash.'%')->page($page,100)->field('id,name,createtime,geohash,latitude,longitude')->select();