How can PHP developers efficiently connect and retrieve neighboring contacts based on postcode proximity?

To efficiently connect and retrieve neighboring contacts based on postcode proximity in PHP, developers can use a combination of geocoding services like Google Maps API to convert postcodes to latitude and longitude coordinates, calculate the distance between contacts using the Haversine formula, and filter out contacts within a specified radius. 

// Example PHP code snippet to retrieve neighboring contacts based on postcode proximity

// Function to calculate the distance between two sets of coordinates using the Haversine formula
function haversineDistance($lat1, $lon1, $lat2, $lon2) {
    $earthRadius = 6371; // in kilometers

    $dLat = deg2rad($lat2 - $lat1);
    $dLon = deg2rad($lon2 - $lon1);

    $a = sin($dLat / 2) * sin($dLat / 2) + cos(deg2rad($lat1)) * cos(deg2rad($lat2)) * sin($dLon / 2) * sin($dLon / 2);
    $c = 2 * asin(sqrt($a));

    $distance = $earthRadius * $c;

    return $distance;
}

// Example usage
$contact1 = ['postcode' => 'SW1A 1AA', 'latitude' => 51.5014, 'longitude' => -0.1419];
$contact2 = ['postcode' => 'W1A 1AA', 'latitude' => 51.5145, 'longitude' => -0.1419];

$distance = haversineDistance($contact1['latitude'], $contact1['longitude'], $contact2['latitude'], $contact2['longitude']);

if ($distance <= 10) {
    echo "Contacts are within 10 kilometers radius";
} else {
    echo "Contacts are not within 10 kilometers radius";
}

Keywords

PHP proximity search postcode database query geolocation

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