Online PHP editor | rfc for t4EaP

<?php class GeoHash { const LEVEL_MAX = 26; // 26位已能达到 0.6m 的精度 const MERCATOR_LENGTH = 40075452.74; // 墨卡托投影下地球的赤道周长 private static $LNG_RANGE = ['min' => -180, 'max' => 180]; private static $LAT_RANGE = ['min' => -90, 'max' => 90]; public function geoRadius() { /** * 数据准备：将地理点通过 getHashInt($lng, $lat) 获取其 hashInt 值，存入redis 的 sorted set * 查询： * 1. 通过 getIntLimit($center_lng, $center_lat, $radius); 获取到九个方格的 hashInt 值和其 range * 2. 用 ZRANGEBYSCORE key hashInt hashInt+range 获取九个方格内的地址点 * 3. 遍历各个点（九个方格点范围略大），计算距离，返回严格符合要求的点 */ } /** * 获取某点geohash对应的Int值 * * @param $lng * @param $lat * * @return number */ public function getHashInt($lng, $lat) { $bits_lng = $this->getBits($lng, self::$LNG_RANGE); $bits_lat = $this->getBits($lat, self::$LAT_RANGE); $bits = $this->assembleBits($bits_lng, $bits_lat); return $this->getFormalInt($bits); } /** * 测试某一目的点是否在中心点N米范围内 * * @param $center_lng * @param $center_lat * @param $radius * @param $aim_lng * @param $aim_lat */ public function testInRadius($center_lng, $center_lat, $radius, $aim_lng, $aim_lat) { $limit = $this->getIntLimit($center_lng, $center_lat, $radius); $int_aim = $this->getHashInt($aim_lng, $aim_lat); $res = 'not_in_radius'; foreach ($limit['cells'] as $int_cell) { if ($int_aim > $int_cell && $int_aim < $int_cell + $limit['range']) { $res = 'in_radius'; break; } } echo $res . PHP_EOL; } /** * 通过二进制哈希串获取到规范化为52位的正整数 * * @param $bits * * @return number */ private function getFormalInt($bits) { $bits_padded = str_pad($bits, self::LEVEL_MAX * 2, '0'); return bindec($bits_padded); } /** * 获取int值的限制 * * @param $lng * @param $lat * @param $radius * * @return array */ private function getIntLimit($lng, $lat, $radius) { $level = $this->getLevel($radius); $bits_lng = $this->getBits($lng, self::$LNG_RANGE, $level); $bits_lat = $this->getBits($lat, self::$LAT_RANGE, $level); $cells = $this->getRoundCells($bits_lng, $bits_lat); $cells['mid'] = $this->getFormalInt($this->assembleBits($bits_lng, $bits_lat)); $range = $this->getLevelRange($level); $limit = [ 'cells' => $cells, 'range' => $range, ]; return $limit; } /** * 通过经度/纬度和其范围值获取到其二进制哈希串 * * @param $loc * @param $range * @param int $level * * @return string */ private function getBits($loc, $range, $level = self::LEVEL_MAX) { $bits = ''; for ($i = 0; $i < $level; $i++) { $mid = ($range['min'] + $range['max']) / 2; if ($loc < $mid) { $bits .= '0'; $range = ['min' => $range['min'], 'max' => $mid]; } else { $bits .= '1'; $range = ['min' => $mid, 'max' => $range['max']]; } } return $bits; } /** * 组合经度和纬度的二进制串 * * @param $lng * @param $lat * * @return string */ private function assembleBits($lng, $lat) { $bits_assembled = ''; $arr_lng = str_split($lng); $arr_lat = str_split($lat); for ($i = 0, $c = count($arr_lng); $i < $c; $i++) { $bits_assembled .= $arr_lat[$i] . $arr_lng[$i]; } return $bits_assembled; } /** * 获取中心格子四周的八个格子 * * @param $bits_lng * @param $bits_lat * * @return mixed */ private function getRoundCells($bits_lng, $bits_lat) { $lng_incr = decbin(bindec($bits_lng) + 1); $lng_decr = decbin(bindec($bits_lng) - 1); $lat_incr = decbin(bindec($bits_lat) + 1); $lat_decr = decbin(bindec($bits_lat) - 1); $cells['mid'] = $this->getFormalInt($this->assembleBits($bits_lng, $bits_lat)); $cells['up'] = $this->getFormalInt($this->assembleBits($bits_lng, $lat_incr)); $cells['down'] = $this->getFormalInt($this->assembleBits($bits_lng, $lat_decr)); $cells['left'] = $this->getFormalInt($this->assembleBits($lng_decr, $bits_lat)); $cells['right'] = $this->getFormalInt($this->assembleBits($lng_incr, $bits_lat)); $cells['left_up'] = $this->getFormalInt($this->assembleBits($lng_decr, $lat_incr)); $cells['right_up'] = $this->getFormalInt($this->assembleBits($lng_incr, $lat_incr)); $cells['left_down'] = $this->getFormalInt($this->assembleBits($lng_incr, $lat_decr)); $cells['right_down'] = $this->getFormalInt($this->assembleBits($lng_incr, $lat_decr)); return $cells; } /** * 通过范围值获取geohash层级 * * @param $range_meter * * @return int */ private function getLevel($range_meter) { $level = 0; $global = self::MERCATOR_LENGTH; while ($global > $range_meter) { $global /= 2; $level++; } return $level; } /** * 通过哈希层级获取每一格子的范围 * * @param $level * * @return number */ private function getLevelRange($level) { $range = pow(2, 2 * (self::LEVEL_MAX - $level)); return $range; } } $geohash = new GeoHash(); // 中心地址：新浪总部大厦 $geohash->testInRadius(116.276231, 40.041143, 3000, 116.276301, 40.041532); // 新浪餐厅 in $geohash->testInRadius(116.276317, 40.04168, 3000, 116.27236, 40.04214); // 百度科技园 in $geohash->testInRadius(116.276317, 40.04168, 3000, 116.274826521, 40.0321647826); // 兰园小区 in $geohash->testInRadius(116.276317, 40.04168, 3000, 116.298505, 40.023749); // 上地医院 in $geohash->testInRadius(116.276317, 40.04168, 3000, 116.31763, 40.01522); // 圆明园 not in

3v4l.org

Active branches

Archived branches