附近搜索 geohash.neighbors 生成周边8个geohash(如下图)，生成的长方形区域，与我要的搜索附近半径几公里以内肯定不相符。找到老外写的 https://github.com/ashwin711/proximityhash 。

需要 php版本代码 @ 我

<?php
/*** author https://my.oschina.net/jszhang* copy2php  https://github.com/ashwin711/proximityhash */// demo
// ProximityHash::create_geohash($lat, $lng, 1000, 6);class ProximityHash
{public static function in_circle_check($latitude, $longitude, $centre_lat, $centre_lon, $radius){$x_diff = $longitude - $centre_lon;$y_diff = $latitude - $centre_lat;if (pow($x_diff, 2) + pow($y_diff, 2) <= pow($radius, 2)) {return true;}return false;}public static function get_centroid($latitude, $longitude, $height, $width){$y_cen = $latitude + ($height / 2);$x_cen = $longitude + ($width / 2);return [$x_cen, $y_cen];}public static function convert_to_latlon($y, $x, $latitude, $longitude){$pi = 3.14159265359;$r_earth = 6371000;$lat_diff = ($y / $r_earth) * (180 / $pi);$lon_diff = ($x / $r_earth) * (180 / $pi) / cos($latitude * $pi / 180);$final_lat = $latitude + $lat_diff;$final_lon = $longitude + $lon_diff;return [$final_lat, $final_lon];}public static function create_geohash($latitude, $longitude, $radius, $precision, $georaptor_flag = false, $minlevel = 1, $maxlevel = 12){$x = 0.0;$y = 0.0;$points    = [];$geohashes = [];$grid_width  = [5009400.0, 1252300.0, 156500.0, 39100.0, 4900.0, 1200.0, 152.9, 38.2, 4.8, 1.2, 0.149, 0.0370];$grid_height = [4992600.0, 624100.0, 156000.0, 19500.0, 4900.0, 609.4, 152.4, 19.0, 4.8, 0.595, 0.149, 0.0199];$height = ($grid_height[$precision - 1]) / 2;$width  = ($grid_width[$precision - 1]) / 2;$lat_moves = intval(ceil($radius / $height));$lon_moves = intval(ceil($radius / $width));foreach (range(0, $lat_moves) as $i) {$temp_lat = $y + $height * $i;foreach (range(0, $lon_moves) as $j) {$temp_lon = $x + $width * $j;if (self::in_circle_check($temp_lat, $temp_lon, $y, $x, $radius)) {list($x_cen, $y_cen) = self::get_centroid($temp_lat, $temp_lon, $height, $width);$points[] = self::convert_to_latlon($y_cen, $x_cen, $latitude, $longitude);$points[] = self::convert_to_latlon(-$y_cen, $x_cen, $latitude, $longitude);$points[] = self::convert_to_latlon($y_cen, -$x_cen, $latitude, $longitude);$points[] = self::convert_to_latlon(-$y_cen, -$x_cen, $latitude, $longitude);}}}foreach ($points as $point) {$geohashes[] = GeoHash::encode($point[0], $point[1], $precision);}$geohashes = array_unique($geohashes);if ($georaptor_flag) {// GeoRaptor我没copy// return GeoRaptor::compress($geohashes, $minlevel, $maxlevel);return $geohashes;} else {return $geohashes;}}}

<?php// author https://my.oschina.net/jszhangclass GeoHash
{const BASE32_CODES      = "0123456789bcdefghjkmnpqrstuvwxyz";const BASE32_CODES_DICT = ['0' => 0, '1' => 1, '2' => 2, '3' => 3, '4' => 4, '5' => 5, '6' => 6, '7' => 7, '8' => 8, '9' => 9, 'b' => 10, 'c' => 11, 'd' => 12, 'e' => 13, 'f' => 14, 'g' => 15, 'h' => 16, 'j' => 17, 'k' => 18, 'm' => 19, 'n' => 20, 'p' => 21, 'q' => 22, 'r' => 23, 's' => 24, 't' => 25, 'u' => 26, 'v' => 27, 'w' => 28, 'x' => 29, 'y' => 30, 'z' => 31];// const BASE32_CODES_DICT = array_flip(explode('', self::BASE32_CODES));/*** Significant Figure Hash Length** This is a quick and dirty lookup to figure out how long our hash* should be in order to guarantee a certain amount of trailing* significant figures. This was calculated by determining the error:* 45/2^(n-1) where n is the number of bits for a latitude or* longitude. Key is # of desired sig figs, value is minimum length of* the geohash.* @type Array*///     Desired sig figs:  0  1  2  3  4   5   6   7   8   9  10const SIGFIG_HASH_LENGTH = [0, 5, 7, 8, 11, 12, 13, 15, 16, 17, 18];public static function encode($latitude, $longitude, $numberOfChars = ''){if ($numberOfChars === 'auto') {$decSigFigsLat   = strlen(strstr($latitude, '.')) - 1;$decSigFigsLong  = strlen(strstr($longitude, '.')) - 1;$numberOfSigFigs = max($decSigFigsLat, $decSigFigsLong);$numberOfChars   = self::SIGFIG_HASH_LENGTH[$numberOfSigFigs];} else if (empty($numberOfChars)) {$numberOfChars = 9;}$chars      = [];$bits       = 0;$bitsTotal  = 0;$hash_value = 0;$maxLat     = 90;$minLat     = -90;$maxLon     = 180;$minLon     = -180;$mid        = 0;while (count($chars) < $numberOfChars) {if ($bitsTotal % 2 === 0) {$mid = ($maxLon + $minLon) / 2;if ($longitude > $mid) {$hash_value = ($hash_value << 1) + 1;$minLon     = $mid;} else {$hash_value = ($hash_value << 1) + 0;$maxLon     = $mid;}} else {$mid = ($maxLat + $minLat) / 2;if ($latitude > $mid) {$hash_value = ($hash_value << 1) + 1;$minLat     = $mid;} else {$hash_value = ($hash_value << 1) + 0;$maxLat     = $mid;}}$bits++;$bitsTotal++;if ($bits === 5) {$chars[]    = self::BASE32_CODES[$hash_value];$bits       = 0;$hash_value = 0;}}return implode('', $chars);}public static function decode($hash_string){$bbox   = self::decode_bbox($hash_string);$lat    = ($bbox[0] + $bbox[2]) / 2;$lon    = ($bbox[1] + $bbox[3]) / 2;$latErr = $bbox[2] - $lat;$lonErr = $bbox[3] - $lon;return ['latitude'  => $lat,'longitude' => $lon,'error'     => ['latitude' => $latErr, 'longitude' => $lonErr],];}public static function decode_bbox($hash_string){$isLon  = true;$maxLat = 90;$minLat = -90;$maxLon = 180;$minLon = -180;$mid;$hashValue = 0;for ($i = 0, $l = strlen($hash_string); $i < $l; $i++) {$code      = $hash_string[$i];$hashValue = self::BASE32_CODES_DICT[$code];for ($bits = 4; $bits >= 0; $bits--) {$bit = ($hashValue >> $bits) & 1;if ($isLon) {$mid = ($maxLon + $minLon) / 2;if ($bit === 1) {$minLon = $mid;} else {$maxLon = $mid;}} else {$mid = ($maxLat + $minLat) / 2;if ($bit === 1) {$minLat = $mid;} else {$maxLat = $mid;}}$isLon = !$isLon;}}return [$minLat, $minLon, $maxLat, $maxLon];}/*** Neighbors** Returns all neighbors' hashstrings clockwise from north around to northwest* 7 0 1* 6 x 2* 5 4 3* @param {String} hash_string* @returns {encoded neighborHashList|Array}*/public static function neighbors($hash_string){$hashstringLength = strlen($hash_string);$lonlat = self::decode($hash_string);$lat    = $lonlat['latitude'];$lon    = $lonlat['longitude'];$latErr = $lonlat['error']['latitude'] * 2;$lonErr = $lonlat['error']['longitude'] * 2;$List = [[1, 0],[1, 1],[0, 1],[-1, 1],[-1, 0],[-1, -1],[0, -1],[1, -1],];$neighborHashList = array_map(function ($neighbor) use ($lat, $lon, $latErr, $lonErr, $hashstringLength) {$neighbor_lat = $lat + $neighbor[0] * $latErr;$neighbor_lon = $lon + $neighbor[1] * $lonErr;return self::encode($neighbor_lat, $neighbor_lon, $hashstringLength);}, $List);return $neighborHashList;}public function get_box($arr){$minLat = $arr[0][1];$minLon = $arr[0][0];$maxLat = $arr[0][1];$maxLon = $arr[0][0];foreach ($arr as $point) {$minLat = $point[1] > $minLat ? $minLat : $point[1];$minLon = $point[0] > $minLon ? $minLon : $point[0];$maxLat = $point[1] < $maxLat ? $maxLat : $point[1];$maxLon = $point[0] < $maxLon ? $maxLon : $point[0];}return [$minLat, $minLon, $maxLat, $maxLon];}
}