C'est peut-être trop tard pour vous, mais je vais quand même répondre, avec une réponse similaire à celle que j'ai donnée à cette question connexe , afin que les futurs visiteurs puissent se référer aux deux questions.
Je ne stockerais pas ces valeurs dans la table des métadonnées post, ou du moins pas seulement là-bas. Vous voulez une table avec post_id, lat, loncolonnes, vous pouvez donc placer un index lat, lonet d' interrogation sur ce point . Cela ne devrait pas être trop difficile à maintenir à jour avec un crochet sur la sauvegarde et la mise à jour des publications.
Lorsque vous interrogez la base de données, vous définissez un cadre de délimitation autour du point de départ, afin de pouvoir effectuer une requête efficace pour toutes les lat, lonpaires entre les bordures Nord-Sud et Est-Ouest du cadre.
Après avoir obtenu ce résultat réduit, vous pouvez effectuer un calcul de distance plus avancé (directions circulaires ou réelles) pour filtrer les emplacements qui se trouvent dans les coins de la zone de délimitation et donc plus loin que vous le souhaitez.
Vous trouverez ici un exemple de code simple qui fonctionne dans la zone d'administration. Vous devez créer vous-même la table de base de données supplémentaire. Le code est ordonné du plus intéressant au moins intéressant.
<?php
/*
Plugin Name: Monkeyman geo test
Plugin URI: http://www.monkeyman.be
Description: Geolocation test
Version: 1.0
Author: Jan Fabry
*/
class Monkeyman_Geo
{
public function __construct()
{
add_action('init', array(&$this, 'registerPostType'));
add_action('save_post', array(&$this, 'saveLatLon'), 10, 2);
add_action('admin_menu', array(&$this, 'addAdminPages'));
}
/**
* On post save, save the metadata in our special table
* (post_id INT, lat DECIMAL(10,5), lon DECIMAL (10,5))
* Index on lat, lon
*/
public function saveLatLon($post_id, $post)
{
if ($post->post_type != 'monkeyman_geo') {
return;
}
$lat = floatval(get_post_meta($post_id, 'lat', true));
$lon = floatval(get_post_meta($post_id, 'lon', true));
global $wpdb;
$result = $wpdb->replace(
$wpdb->prefix . 'monkeyman_geo',
array(
'post_id' => $post_id,
'lat' => $lat,
'lon' => $lon,
),
array('%s', '%F', '%F')
);
}
public function addAdminPages()
{
add_management_page( 'Quick location generator', 'Quick generator', 'edit_posts', __FILE__ . 'generator', array($this, 'doGeneratorPage'));
add_management_page( 'Location test', 'Location test', 'edit_posts', __FILE__ . 'test', array($this, 'doTestPage'));
}
/**
* Simple test page with a location and a distance
*/
public function doTestPage()
{
if (!array_key_exists('search', $_REQUEST)) {
$default_lat = ini_get('date.default_latitude');
$default_lon = ini_get('date.default_longitude');
echo <<<EOF
<form action="" method="post">
<p>Center latitude: <input size="10" name="center_lat" value="{$default_lat}"/>
<br/>Center longitude: <input size="10" name="center_lon" value="{$default_lon}"/>
<br/>Max distance (km): <input size="5" name="max_distance" value="100"/></p>
<p><input type="submit" name="search" value="Search!"/></p>
</form>
EOF;
return;
}
$center_lon = floatval($_REQUEST['center_lon']);
$center_lat = floatval($_REQUEST['center_lat']);
$max_distance = floatval($_REQUEST['max_distance']);
var_dump(self::getPostsUntilDistanceKm($center_lon, $center_lat, $max_distance));
}
/**
* Get all posts that are closer than the given distance to the given location
*/
public static function getPostsUntilDistanceKm($center_lon, $center_lat, $max_distance)
{
list($north_lat, $east_lon, $south_lat, $west_lon) = self::getBoundingBox($center_lat, $center_lon, $max_distance);
$geo_posts = self::getPostsInBoundingBox($north_lat, $east_lon, $south_lat, $west_lon);
$close_posts = array();
foreach ($geo_posts as $geo_post) {
$post_lat = floatval($geo_post->lat);
$post_lon = floatval($geo_post->lon);
$post_distance = self::calculateDistanceKm($center_lat, $center_lon, $post_lat, $post_lon);
if ($post_distance < $max_distance) {
$close_posts[$geo_post->post_id] = $post_distance;
}
}
return $close_posts;
}
/**
* Select all posts ids in a given bounding box
*/
public static function getPostsInBoundingBox($north_lat, $east_lon, $south_lat, $west_lon)
{
global $wpdb;
$sql = $wpdb->prepare('SELECT post_id, lat, lon FROM ' . $wpdb->prefix . 'monkeyman_geo WHERE lat < %F AND lat > %F AND lon < %F AND lon > %F', array($north_lat, $south_lat, $west_lon, $east_lon));
return $wpdb->get_results($sql, OBJECT_K);
}
/* Geographical calculations: distance and bounding box */
/**
* Calculate the distance between two coordinates
* http://stackoverflow.com/questions/365826/calculate-distance-between-2-gps-coordinates/1416950#1416950
*/
public static function calculateDistanceKm($a_lat, $a_lon, $b_lat, $b_lon)
{
$d_lon = deg2rad($b_lon - $a_lon);
$d_lat = deg2rad($b_lat - $a_lat);
$a = pow(sin($d_lat/2.0), 2) + cos(deg2rad($a_lat)) * cos(deg2rad($b_lat)) * pow(sin($d_lon/2.0), 2);
$c = 2 * atan2(sqrt($a), sqrt(1-$a));
$d = 6367 * $c;
return $d;
}
/**
* Create a box around a given point that extends a certain distance in each direction
* http://www.colorado.edu/geography/gcraft/warmup/aquifer/html/distance.html
*
* @todo: Mind the gap at 180 degrees!
*/
public static function getBoundingBox($center_lat, $center_lon, $distance_km)
{
$one_lat_deg_in_km = 111.321543; // Fixed
$one_lon_deg_in_km = cos(deg2rad($center_lat)) * 111.321543; // Depends on latitude
$north_lat = $center_lat + ($distance_km / $one_lat_deg_in_km);
$south_lat = $center_lat - ($distance_km / $one_lat_deg_in_km);
$east_lon = $center_lon - ($distance_km / $one_lon_deg_in_km);
$west_lon = $center_lon + ($distance_km / $one_lon_deg_in_km);
return array($north_lat, $east_lon, $south_lat, $west_lon);
}
/* Below this it's not interesting anymore */
/**
* Generate some test data
*/
public function doGeneratorPage()
{
if (!array_key_exists('generate', $_REQUEST)) {
$default_lat = ini_get('date.default_latitude');
$default_lon = ini_get('date.default_longitude');
echo <<<EOF
<form action="" method="post">
<p>Number of posts: <input size="5" name="post_count" value="10"/></p>
<p>Center latitude: <input size="10" name="center_lat" value="{$default_lat}"/>
<br/>Center longitude: <input size="10" name="center_lon" value="{$default_lon}"/>
<br/>Max distance (km): <input size="5" name="max_distance" value="100"/></p>
<p><input type="submit" name="generate" value="Generate!"/></p>
</form>
EOF;
return;
}
$post_count = intval($_REQUEST['post_count']);
$center_lon = floatval($_REQUEST['center_lon']);
$center_lat = floatval($_REQUEST['center_lat']);
$max_distance = floatval($_REQUEST['max_distance']);
list($north_lat, $east_lon, $south_lat, $west_lon) = self::getBoundingBox($center_lat, $center_lon, $max_distance);
add_action('save_post', array(&$this, 'setPostLatLon'), 5);
$precision = 100000;
for ($p = 0; $p < $post_count; $p++) {
self::$currentRandomLat = mt_rand($south_lat * $precision, $north_lat * $precision) / $precision;
self::$currentRandomLon = mt_rand($west_lon * $precision, $east_lon * $precision) / $precision;
$location = sprintf('(%F, %F)', self::$currentRandomLat, self::$currentRandomLon);
$post_data = array(
'post_status' => 'publish',
'post_type' => 'monkeyman_geo',
'post_content' => 'Point at ' . $location,
'post_title' => 'Point at ' . $location,
);
var_dump(wp_insert_post($post_data));
}
}
public static $currentRandomLat = null;
public static $currentRandomLon = null;
/**
* Because I didn't know how to save meta data with wp_insert_post,
* I do it here
*/
public function setPostLatLon($post_id)
{
add_post_meta($post_id, 'lat', self::$currentRandomLat);
add_post_meta($post_id, 'lon', self::$currentRandomLon);
}
/**
* Register a simple post type for us
*/
public function registerPostType()
{
register_post_type(
'monkeyman_geo',
array(
'label' => 'Geo Location',
'labels' => array(
'name' => 'Geo Locations',
'singular_name' => 'Geo Location',
'add_new' => 'Add new',
'add_new_item' => 'Add new location',
'edit_item' => 'Edit location',
'new_item' => 'New location',
'view_item' => 'View location',
'search_items' => 'Search locations',
'not_found' => 'No locations found',
'not_found_in_trash' => 'No locations found in trash',
'parent_item_colon' => null,
),
'description' => 'Geographical locations',
'public' => true,
'exclude_from_search' => false,
'publicly_queryable' => true,
'show_ui' => true,
'menu_position' => null,
'menu_icon' => null,
'capability_type' => 'post',
'capabilities' => array(),
'hierarchical' => false,
'supports' => array(
'title',
'editor',
'custom-fields',
),
'register_meta_box_cb' => null,
'taxonomies' => array(),
'permalink_epmask' => EP_PERMALINK,
'rewrite' => array(
'slug' => 'locations',
),
'query_var' => true,
'can_export' => true,
'show_in_nav_menus' => true,
)
);
}
}
$monkeyman_Geo_instance = new Monkeyman_Geo();