这年头和LBS相关的应用越来越火. 从foursquare的热闹程度就可见一般, 更不用说微信、陌陌了 (什么, 没听过 foursquare... 哥们, 你 out 了). 和 LBS有关的应用一般都包括一些共同的操作, 最常见的一个, 就是找附近的东东(餐馆, 商店, 妞....). 所以, 这里就抛出了一个问题, 怎样才能在大量经纬度数据中检索出附近的点呢?
geohash能做到 @一个开发者
require_once('geohash.class.php');
$geohash = new Geohash;
//得到这点的hash值
$hash = $geohash->encode(39.98123848, 116.30683690);
//取前缀,前缀约长范围越小
$prefix = substr($hash, 0, 6);
//取出相邻八个区域
$neighbors = $geohash->neighbors($prefix);
array_push($neighbors, $prefix);
print_r($neighbors);
//得到9个geohash值
Array
(
[top] => wx4eqx
[bottom] => wx4eqt
[right] => wx4eqy
[left] => wx4eqq
[topleft] => wx4eqr
[topright] => wx4eqz
[bottomright] => wx4eqv
[bottomleft] => wx4eqm
[0] => wx4eqw
)
SELECT * FROM xy WHERE geohash LIKE 'wx4eqw%';
SELECT * FROM xy WHERE geohash LIKE 'wx4eqx%';
SELECT * FROM xy WHERE geohash LIKE 'wx4eqt%';
SELECT * FROM xy WHERE geohash LIKE 'wx4eqy%';
SELECT * FROM xy WHERE geohash LIKE 'wx4eqq%';
SELECT * FROM xy WHERE geohash LIKE 'wx4eqr%';
SELECT * FROM xy WHERE geohash LIKE 'wx4eqz%';
SELECT * FROM xy WHERE geohash LIKE 'wx4eqv%';
SELECT * FROM xy WHERE geohash LIKE 'wx4eqm%';
索引:
数据:
EXPLAIN SELECT * FROM xy WHERE geohash LIKE 'wx4eqw%';
其他资料: