PHP geolocation search and calculate distance

This article mainly introduces PHP geographical location search and distance calculation. Friends who are interested can refer to it. I hope it will be helpful to everyone.

Geographical location search
LBS stores the latitude and longitude coordinates of each location, searches for nearby locations, and establishes a geographical location index to improve query efficiency.
Mongodb geographical location index, 2d and 2dsphere, corresponding to plane and sphere.

1. Create the coordinates of the storage location of the lbs collection

use lbs; 
 
db.lbs.insert( 
  { 
    loc:{ 
      type: "Point", 
      coordinates: [113.332264, 23.156206] 
    }, 
    name: "广州东站" 
  } 
) 
 
db.lbs.insert( 
  { 
    loc:{ 
      type: "Point", 
      coordinates: [113.330611, 23.147234] 
    }, 
    name: "林和西" 
  } 
) 
 
db.lbs.insert( 
  { 
    loc:{ 
      type: "Point", 
      coordinates: [113.328095, 23.165376] 
    }, 
    name: "天平架" 
  } 
)

2. Create a geographical location index

db.lbs.ensureIndex( 
  { 
    loc: "2dsphere" 
  } 
)

3. Query nearby coordinates
The current location is: Times Square,
Coordinates:

113.323568, 23.146436

Search for points within one kilometer nearby, sort from nearest to far

db.lbs.find( 
  { 
    loc: { 
      $near:{ 
        $geometry:{ 
          type: "Point", 
          coordinates: [113.323568, 23.146436] 
        }, 
        $maxDistance: 1000 
      } 
    } 
  } 
)

Search results:

The code is as follows:

{ "_id" : ObjectId("556a651996f1ac2add8928fa"), "loc" : { "type " : "Point", "coordinates" : [ 113.330611, 23.147234 ] }, "name" : "Lin Hexi" }

##The php code is as follows:

<?php 
// 连接mongodb 
function conn($dbhost, $dbname, $dbuser, $dbpasswd){ 
  $server = &#39;mongodb://&#39;.$dbuser.&#39;:&#39;.$dbpasswd.&#39;@&#39;.$dbhost.&#39;/&#39;.$dbname; 
  try{ 
    $conn = new MongoClient($server); 
    $db = $conn->selectDB($dbname); 
  } catch (MongoException $e){ 
    throw new ErrorException(&#39;Unable to connect to db server. Error:&#39; . $e->getMessage(), 31); 
  } 
  return $db; 
} 
 
// 插入坐标到mongodb 
function add($dbconn, $tablename, $longitude, $latitude, $name){ 
  $index = array(&#39;loc&#39;=>&#39;2dsphere&#39;); 
  $data = array( 
      &#39;loc&#39; => array( 
          &#39;type&#39; => &#39;Point&#39;, 
          &#39;coordinates&#39; => array(doubleval($longitude), doubleval($latitude)) 
      ), 
      &#39;name&#39; => $name 
  ); 
  $coll = $dbconn->selectCollection($tablename); 
  $coll->ensureIndex($index); 
  $result = $coll->insert($data, array(&#39;w&#39; => true)); 
  return (isset($result[&#39;ok&#39;]) && !empty($result[&#39;ok&#39;])) ? true : false; 
} 
 
// 搜寻附近的坐标 
function query($dbconn, $tablename, $longitude, $latitude, $maxdistance, $limit=10){ 
  $param = array( 
    &#39;loc&#39; => array( 
      &#39;$nearSphere&#39; => array( 
        &#39;$geometry&#39; => array( 
          &#39;type&#39; => &#39;Point&#39;, 
          &#39;coordinates&#39; => array(doubleval($longitude), doubleval($latitude)),  
        ), 
        &#39;$maxDistance&#39; => $maxdistance*1000 
      ) 
    ) 
  ); 
 
  $coll = $dbconn->selectCollection($tablename); 
  $cursor = $coll->find($param); 
  $cursor = $cursor->limit($limit); 
   
  $result = array(); 
  foreach($cursor as $v){ 
    $result[] = $v; 
  }  
 
  return $result; 
} 
 
$db = conn(&#39;localhost&#39;,&#39;lbs&#39;,&#39;root&#39;,&#39;123456&#39;); 
 
// 随机插入100条坐标纪录 
for($i=0; $i<100; $i++){ 
  $longitude = &#39;113.3&#39;.mt_rand(10000, 99999); 
  $latitude = &#39;23.15&#39;.mt_rand(1000, 9999); 
  $name = &#39;name&#39;.mt_rand(10000,99999); 
  add($db, &#39;lbs&#39;, $longitude, $latitude, $name); 
} 
 
// 搜寻一公里内的点 
$longitude = 113.323568; 
$latitude = 23.146436; 
$maxdistance = 1; 
$result = query($db, &#39;lbs&#39;, $longitude, $latitude, $maxdistance); 
print_r($result); 
?>

To demonstrate the php code, you first need to create a user and execute auth in the lbs of mongodb. The method is as follows:

use lbs; 
db.createUser( 
  { 
    "user":"root", 
    "pwd":"123456", 
    "roles":[] 
  } 
) 
 
db.auth( 
  { 
    "user":"root", 
    "pwd":"123456" 
  } 
)

Calculate the distance between two geographical coordinates
Function: Calculate the spherical distance between two points based on the pi ratio, the earth's radius coefficient and the longitude and latitude of the two point coordinates.

Get the coordinate distance between two points:

<?php
/**
 * 计算两点地理坐标之间的距离
 * @param Decimal $longitude1 起点经度
 * @param Decimal $latitude1 起点纬度
 * @param Decimal $longitude2 终点经度 
 * @param Decimal $latitude2 终点纬度
 * @param Int   $unit    单位 1:米 2:公里
 * @param Int   $decimal  精度 保留小数位数
 * @return Decimal
 */
function getDistance($longitude1, $latitude1, $longitude2, $latitude2, $unit=2, $decimal=2){

  $EARTH_RADIUS = 6370.996; // 地球半径系数
  $PI = 3.1415926;

  $radLat1 = $latitude1 * $PI / 180.0;
  $radLat2 = $latitude2 * $PI / 180.0;

  $radLng1 = $longitude1 * $PI / 180.0;
  $radLng2 = $longitude2 * $PI /180.0;

  $a = $radLat1 - $radLat2;
  $b = $radLng1 - $radLng2;

  $distance = 2 * asin(sqrt(pow(sin($a/2),2) + cos($radLat1) * cos($radLat2) * pow(sin($b/2),2)));
  $distance = $distance * $EARTH_RADIUS * 1000;

  if($unit==2){
    $distance = $distance / 1000;
  }

  return round($distance, $decimal);

}

// 起点坐标
$longitude1 = 113.330405;
$latitude1 = 23.147255;

// 终点坐标
$longitude2 = 113.314271;
$latitude2 = 23.1323;

$distance = getDistance($longitude1, $latitude1, $longitude2, $latitude2, 1);
echo $distance.&#39;m&#39;; // 2342.38m

$distance = getDistance($longitude1, $latitude1, $longitude2, $latitude2, 2);
echo $distance.&#39;km&#39;; // 2.34km

?>

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