Calculates the distance between two address using PHP and Google Maps

distrance-matrix-php-google-maps.php

/**
 * @function getDistance()
 * Calculates the distance between two address
 * 
 * @params
 * $addressFrom - Starting point
 * $addressTo - End point
 * $unit - Unit type
 * 
 */
function getDistance($addressFrom, $addressTo, $unit = ''){
    // Google API key
    $apiKey = 'Your_Google_API_Key';
    
    // Change address format
    $formattedAddrFrom   = str_replace(' ', '+', $addressFrom);
    $formattedAddrTo     = str_replace(' ', '+', $addressTo);
    
    // Geocoding API request with start address
    $geocodeFrom = file_get_contents('https://maps.googleapis.com/maps/api/geocode/json?address='.$formattedAddrFrom.'&sensor=false&key='.$apiKey);
    $outputFrom = json_decode($geocodeFrom);
    if(!empty($outputFrom->error_message)){
        return $outputFrom->error_message;
    }
    
    // Geocoding API request with end address
    $geocodeTo = file_get_contents('https://maps.googleapis.com/maps/api/geocode/json?address='.$formattedAddrTo.'&sensor=false&key='.$apiKey);
    $outputTo = json_decode($geocodeTo);
    if(!empty($outputTo->error_message)){
        return $outputTo->error_message;
    }
    
    // Get latitude and longitude from the geodata
    $latitudeFrom    = $outputFrom->results[0]->geometry->location->lat;
    $longitudeFrom    = $outputFrom->results[0]->geometry->location->lng;
    $latitudeTo        = $outputTo->results[0]->geometry->location->lat;
    $longitudeTo    = $outputTo->results[0]->geometry->location->lng;
    
    // Calculate distance between latitude and longitude
    $theta   = $longitudeFrom - $longitudeTo;
    $dist    = sin(deg2rad($latitudeFrom)) * sin(deg2rad($latitudeTo)) +  cos(deg2rad($latitudeFrom)) * cos(deg2rad($latitudeTo)) * cos(deg2rad($theta));
    $dist    = acos($dist);
    $dist    = rad2deg($dist);
    $miles   = $dist * 60 * 1.1515;
    
    // Convert unit and return distance
    $unit = strtoupper($unit);
    if($unit == "K"){
        return round($miles * 1.609344, 2).' km';
    }elseif($unit == "M"){
        return round($miles * 1609.344, 2).' meters';
    }else{
        return round($miles, 2).' miles';
    }
}

// Call the getDistance() function and pass two addresses between from which you want to calculate distance.

$addressFrom = 'Insert start address';
$addressTo   = 'Insert end address';

// Get distance in km
$distance = getDistance($addressFrom, $addressTo, "K");