sudo apt-get install libgeoip-dev

pecl install geoip-1.1.0 

extension=geoip.so
geoip.custom_directory="/usr/share/GeoIP"

wget http://geolite.maxmind.com/download/geoip/database/GeoLiteCity.dat.gz
gunzip GeoLiteCity.dat.gz
sudo mkdir -v /usr/share/GeoIP
sudo mv -v GeoLiteCity.dat /usr/share/GeoIP/GeoIPCity.dat

php -a

<?php
print_r(geoip_record_by_name('106.37.165.80')); //回车后按Ctrl+D运行
Array
(
 [continent_code] => AS
 [country_code] => CN
 [country_code3] => CHN
 [country_name] => China //国家
 [region] => 22
 [city] => Beijing //城市
 [postal_code] =>
 [latitude] => 39.928901672363 //纬度
 [longitude] => 116.38829803467 //经度
 [dma_code] => 0
 [area_code] => 0
)

traceroute www.oschina.net 

 61.145.122.155

sudo apt-get install geoip-bin geoip-database
geoiplookup 61.145.122.155 -f /usr/share/GeoIP/GeoIP.dat
GeoIP Country Edition: CN, China

geoiplookup 61.145.122.155 -f /usr/share/GeoIP/GeoIPCity.dat
GeoIP City Edition, Rev 1: CN, 30, Guangdong, Guangzhou, N/A, 23.116699, 113.250000, 0, 0

geoip_record_by_name($_SERVER['REMOTE_ADDR'])

geoip_record_by_name()

<?php
//以当前用户经纬度为中心,查询5000米内的其他用户
$y = 5000 / 110852; //纬度的范围
$x = 5000 / (111320*cos($lat)); //经度的范围
$sql = '
 select * from user where 
 lat >= ($lat-$y) and lat <= ($lat+$y) and 
 lon >= ($lon-$x) and lon <= ($lon+$x);
';

($lat-$y) <= lat <= ($lat+$y)
($lon-$x) <= lon <= ($lon+$x)

<?php
function distance($lat1, $lon1, $lat2, $lon2) {
 $R = 6371393; //地球平均半径,单位米
 $dlat = deg2rad($lat2-$lat1);
 $dlon = deg2rad($lon2-$lon1);
 $a = pow(sin($dlat/2), 2) + cos(deg2rad($lat1)) * cos(deg2rad($lat2)) * pow(sin($dlon/2), 2);
 $c = 2 * atan2(sqrt($a), sqrt(1-$a));
 $d = $R * $c;
 return round($d);
}
echo distance(0, 0, -1, 0); // 111202米

<?php
$arr = array(
 'win' => array(
  'dis' => 1024,
  'age' => 31
 ),
 'osx' => array(
  'dis' => 512,
  'age' => 15
 ),
 'lin' => array(
  'dis' => 512,
  'age' => 25
 )
);
foreach($arr as $k => $v) {
 $sort['dis'][$k] = $v['dis'];
 $sort['age'][$k] = $v['age'];
}
//先按距离升序排序,如果距离相同,则按年龄降序排序
array_multisort($sort['dis'], SORT_ASC, $sort['age'], SORT_DESC, $arr);
echo json_encode($arr);
//{"lin":{"dis":512,"age":25},"osx":{"dis":512,"age":15},"win":{"dis":1024,"age":31}}