PHP geo-search and calculate distances

This article mainly introduces the PHP geographical location search and calculates the distance, the interest friend's reference, hoped to be helpful to everybody.

Location Search
LBS, which stores the latitude and longitude coordinates of each location, searches for nearby locations and establishes a geographical index to improve query efficiency.
MongoDB geolocation Index, 2d and 2dsphere, corresponds to planar and spherical surfaces.

1. Create lbs collection Storage location coordinates

use lbs;  Db.lbs.insert (   {     loc:{       type: "point",       coordinates: [113.332264, 23.156206]     },     name: "Guangzhou East railway Station"   } )  Db.lbs.insert (   {     loc:{       type: "point",       coordinates: [113.330611, 23.147234]     },     name: "Forest and West"   })  Db.lbs.insert (   {     loc:{       type: "point",       coordinates: [113.328095, 23.165376]     },     name: "Balance Stand"   })

2. Create a geo-index

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

3. Query for nearby coordinates
The current position is: Times Square,
Coordinate:

113.323568, 23.146436

Search nearby points within a kilometer, sorted by near to far

Db.lbs.find (   {     loc: {       $near: {         $geometry: {           type: ' point ',           coordinates: [113.323568, 23.146436]}         ,         $maxDistance: +}}   )

Search results:

The code is as follows:

{"_id": ObjectId ("556a651996f1ac2add8928fa"), "loc": {"type": "Point", "coordinates": [113.330611, 23.147234]}, " Name ":" Forest and West "}

The PHP code is as follows:

<?php//Connect MONGODB function conn ($dbhost, $dbname, $dbuser, $dbpasswd) {$server = ' mongodb://'. $dbuser. ': ' $dbpasswd. ' @ '. $dbhost. '   /'. $dbname;     try{$conn = new Mongoclient ($server);   $db = $conn->selectdb ($dbname); } catch (Mongoexception $e) {throw new errorexception (' Unable to connect to DB server. Error: '.   $e->getmessage (), 31); } return $db; }//Insert coordinates to MongoDB function add ($dbconn, $tablename, $longitude, $latitude, $name) {$index = array (' loc ' = ' 2dsphere ')   ; $data = Array (' loc ' = = Array (' type ' = ' = ' point ', ' coordinates ' = = Array (doubleval ($lon   Gitude), Doubleval ($latitude))), ' name ' = = $name);   $coll = $dbconn->selectcollection ($tablename);   $coll->ensureindex ($index);   $result = $coll->insert ($data, Array (' w ' = true)); Return (Isset ($result [' OK ']) &&!empty ($result [' OK '])? True:false; }//Search nearby coordinates function query ($dbconn, $tablename, $longitude, $latitude, $maxdIstance, $limit =10) {$param = array (' loc ' = = Array (' $nearSphere ' = = Array (' $geometry ' = = A          Rray (' type ' = ' point ', ' coordinates ' = ' = ' Array (doubleval ($longitude), Doubleval ($latitude)),    ), ' $maxDistance ' =-$maxdistance *1000));   $coll = $dbconn->selectcollection ($tablename);   $cursor = $coll->find ($param);      $cursor = $cursor->limit ($limit);   $result = Array ();   foreach ($cursor as $v) {$result [] = $v; } return $result;  } $DB = conn (' localhost ', ' lbs ', ' root ', ' 123456 ');   Randomly insert 100 coordinate records for ($i =0; $i <100; $i + +) {$longitude = ' 113.3 '. Mt_rand (10000, 99999);   $latitude = ' 23.15 '. Mt_rand (1000, 9999);   $name = ' name '. Mt_rand (10000,99999); Add ($db, ' lbs ', $longitude, $latitude, $name); }//Search for points within one kilometer $longitude = 113.323568; $latitude = 23.146436; $maxdistance = 1; $result = Query ($db, ' lbs ', $longitude, $latitude, $maxdistance); Print_r ($result);?>

To demonstrate PHP code, you first need to create users and execute auth in MongoDB's lbs. Here's how:

Use lbs; Db.createuser (   {     "user": "Root",     "pwd": "123456",     "roles": []   })  Db.auth (   {     "user ":" Root ",     " pwd ":" 123456 "   })

Calculate the distance from the two-point geographic coordinates
Function: Calculates the spherical distance between two points according to the latitude and longitude of pi and earth radius coefficients and coordinates of two points.

Get two point coordinate distance:

<?php/** * Calculates the distance between two points of geographic coordinates * @param decimal $longitude 1 beginning Longitude * @param decimal $latitude 1 beginning latitude * @param Decimal $longitude 2 Finish Longitude * @param Decimal $latitude 2 End latitude * @param Int $unit Unit 1: M 2: km * @param Int $decimal precision reserved decimal place * @return Decimal */function getdistance ($longitude 1, $latitude 1, $longitude 2, $latitude 2, $unit =2, $decimal =2) {$EARTH _radius = 6 370.996;  The radius coefficient of the earth $PI = 3.1415926;  $radLat 1 = $latitude 1 * $PI/180.0;  $radLat 2 = $latitude 2 * $PI/180.0;  $radLng 1 = $longitude 1 * $PI/180.0;  $radLng 2 = $longitude 2 * $PI/180.0;  $a = $radLat 1-$radLat 2;  $b = $radLng 1-$radLng 2;  $distance = 2 * ASIN (sqrt (Pow (sin ($a/2), 2) + cos ($radLat 1) * cos ($radLat 2) * POW (sin ($b/2), 2)));  $distance = $distance * $EARTH _radius * 1000;  if ($unit ==2) {$distance = $distance/1000; } return Round ($distance, $decimal);} Start coordinates $longitude1 = 113.330405; $latitude 1 = 23.147255;//end point coordinates $longitude2 = 113.314271; $latitude 2 = 23.1323; $distance = ge Tdistance ($longitude 1, $latitude 1, $lOngitude2, $latitude 2, 1); Echo $distance. ' m '; 2342.38m$distance = Getdistance ($longitude 1, $latitude 1, $longitude 2, $latitude 2, 2); Echo $distance. ' Km '; 2.34km?>

Summary : The above is the entire content of this article, I hope to be able to help you learn.

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