<?php

$link = 'http://www.meb.gov.tr/baglantilar/okullar/index.php?ILKODU=28';

// site güvenlik önlemi koyarsa, 
// yada herhangi bir limit'e takılırsanız
// cURL kullanın.
// 
// sitenin içeriğini aldık ve tüm boşlukları temizledik
$icerik = preg_replace('/\s+/', '', file_get_contents($link));

// içerikden ihtiyacımız olan data-veri içerisindeki değerleri aldık
preg_match_all('#data-veri="(.*?)"#', $icerik, $veriler);


$linkler = array_map(function($veri) {
    $harita_icerik = preg_replace('/\s+/', '', file_get_contents(
        "http://mebk12.meb.gov.tr/meb_iys_dosyalar/harita.php?bb={$veri}/"
    ));

    preg_match_all('#src="(.*?)"#', $harita_icerik, $link);

    return trim($link[1][1]);

}, $veriler[1]);

echo '<pre>';
var_dump($linkler);

array(20) {
  [0]=>
  string(131) "https://www.google.com/maps/embed/v1/place?q=40.3199952933783,38.764816132922306&key=AIzaSyBmKTe5T1h3e6cUhngLRXpzd4H6Yjys41k&zoom=9"
  [1]=>
  string(131) "https://www.google.com/maps/embed/v1/place?q=40.32918912359517,38.7635367192222&key=AIzaSyBmKTe5T1h3e6cUhngLRXpzd4H6Yjys41k&zoom=18"
  [2]=>
  string(132) "https://www.google.com/maps/embed/v1/place?q=40.32332656557657,38.75963410510553&key=AIzaSyBmKTe5T1h3e6cUhngLRXpzd4H6Yjys41k&zoom=17"
  [3]=>
  string(134) "https://www.google.com/maps/embed/v1/place?q=40.322972791861964,38.759355155367984&key=AIzaSyBmKTe5T1h3e6cUhngLRXpzd4H6Yjys41k&zoom=17"
  [4]=>
  string(130) "https://www.google.com/maps/embed/v1/place?q=40.3181895074577,38.7712990321113&key=AIzaSyBmKTe5T1h3e6cUhngLRXpzd4H6Yjys41k&zoom=10"
  [5]=>
  string(132) "https://www.google.com/maps/embed/v1/place?q=40.31892368898695,38.76602849139704&key=AIzaSyBmKTe5T1h3e6cUhngLRXpzd4H6Yjys41k&zoom=15"
  [6]=>
  string(132) "https://www.google.com/maps/embed/v1/place?q=40.31423624239258,38.83878072871698&key=AIzaSyBmKTe5T1h3e6cUhngLRXpzd4H6Yjys41k&zoom=13"
  [7]=>
  string(134) "https://www.google.com/maps/embed/v1/place?q=40.325622982240425,38.760331479449405&key=AIzaSyBmKTe5T1h3e6cUhngLRXpzd4H6Yjys41k&zoom=13"
  [8]=>
  string(132) "https://www.google.com/maps/embed/v1/place?q=40.32419361007744,38.76339724435343&key=AIzaSyBmKTe5T1h3e6cUhngLRXpzd4H6Yjys41k&zoom=18"
  [9]=>
  string(133) "https://www.google.com/maps/embed/v1/place?q=40.323897098470454,38.91696175708307&key=AIzaSyBmKTe5T1h3e6cUhngLRXpzd4H6Yjys41k&zoom=15"
  [10]=>
  string(133) "https://www.google.com/maps/embed/v1/place?q=40.317696640169764,38.77141436709894&key=AIzaSyBmKTe5T1h3e6cUhngLRXpzd4H6Yjys41k&zoom=17"
  [11]=>
  string(131) "https://www.google.com/maps/embed/v1/place?q=40.9357065623117,38.21567138804926&key=AIzaSyBmKTe5T1h3e6cUhngLRXpzd4H6Yjys41k&zoom=16"
  [12]=>
  string(132) "https://www.google.com/maps/embed/v1/place?q=40.93626580830249,38.21550240888132&key=AIzaSyBmKTe5T1h3e6cUhngLRXpzd4H6Yjys41k&zoom=19"
  [13]=>
  string(131) "https://www.google.com/maps/embed/v1/place?q=40.71940280544572,38.10153803004755&key=AIzaSyBmKTe5T1h3e6cUhngLRXpzd4H6Yjys41k&zoom=9"
  [14]=>
  string(134) "https://www.google.com/maps/embed/v1/place?q=40.936411697782304,38.211251107592716&key=AIzaSyBmKTe5T1h3e6cUhngLRXpzd4H6Yjys41k&zoom=17"
  [15]=>
  string(131) "https://www.google.com/maps/embed/v1/place?q=40.6580628417992,38.08750471248163&key=AIzaSyBmKTe5T1h3e6cUhngLRXpzd4H6Yjys41k&zoom=13"
  [16]=>
  string(133) "https://www.google.com/maps/embed/v1/place?q=40.937684164584546,38.23165735377802&key=AIzaSyBmKTe5T1h3e6cUhngLRXpzd4H6Yjys41k&zoom=15"
  [17]=>
  string(134) "https://www.google.com/maps/embed/v1/place?q=40.931070311797285,38.225777951617374&key=AIzaSyBmKTe5T1h3e6cUhngLRXpzd4H6Yjys41k&zoom=15"
  [18]=>
  string(132) "https://www.google.com/maps/embed/v1/place?q=40.93676831515449,38.21133693828119&key=AIzaSyBmKTe5T1h3e6cUhngLRXpzd4H6Yjys41k&zoom=17"
  [19]=>
  string(131) "https://www.google.com/maps/embed/v1/place?q=40.9367521053157,38.21115454806818&key=AIzaSyBmKTe5T1h3e6cUhngLRXpzd4H6Yjys41k&zoom=18"
}