Googlemap very slow

<?php
require('GoogleMapAPIv3.class.php');

                $gmap = new GoogleMapAPI();
                $gmap->setDivId('test1');
                $gmap->setDirectionDivId('route');
                $gmap->setCenter('Privas');
                $gmap->setEnableWindowZoom(true);

               // $gmap->setDisplayDirectionFields(true);
              $gmap->setClusterer(false);
                $gmap->setSize('385px','439px');
                $gmap->setZoom(9);
                $gmap->setLang('fr');
                $gmap->setDefaultHideMarker(false);
                // $gmap->addDirection('nantes','paris');


				// $gmap->setIconSize(20,34);
                $gmap->addArrayMarkerByAddress($coordtab,'cat1');



$parent=$_GET['id'];
$c = $modx->newQuery('modResource');
	$c->where(array(
	    $modx->resource->get('id'),
	    ));

$resources = $modx->getCollection('modResource',$c);

$adressedep = $adressedep;
$longitude = $longitude;
$latitude = $latitude;
$adressecode = $gmap->addMarkerByCoords($longitude,$latitude);

foreach($resources as $resource){
  if ($resource->getTVValue("adresse_terrain")==""){

  }else{
	$gmap->addMarkerByCoords($resource->getTVValue("latitude"),$resource->getTVValue("longitude"),$resource->getTVValue("adresse_terrain"),"<span style='color:#B70B01;font-weight:bold;'> Terrain à ".$resource->getTVValue("adresse_terrain")."</span>,<br/><img src='".$resource->getTVValue("ma_tv")."' style='width:70px; float:left; margin-right:5px;margin-top:10px;'/><p style='font-size:11px;width:255px;'>".$resource->getTVValue("description_terrain")."</p> <em>A partir de ".$resource->getTVValue("tarif")." € </em> <br/> <a name='bt_details' href='?id=".$resource->get('id')."' class='bt_terrain'>>> En savoir +</a><br/><a style='font-size:11px;' href='http://www.terrains-ardeche.fr/index.php?id=2&code_postal=Code+postal&Lieu=".$resource->getTVValue("adresse_terrain")."&sup=0&prix=A'>Voir tous les terrains à ".$resource->getTVValue("adresse_terrain")." </a><br/>");
  }
}

              $gmap->generate();
                echo $gmap->getGoogleMap();

$c->where(
    array('parent:=' => $modx->resource->get('id')
);

//also you can use $modx->resource->id to get the id of the resource (or you should be able to)