// map markers
    var map;
    var markers = [];
    markers[1] = [];
    markers[2] = []; 
    var cur_type = [true,true];
    var markers_list = [];
    var markers_source = [];
    var markers_xy = [];
    var markers_pcs = [];
    var markers_title = [];
    var topRight;
    var bottomLeft;
    var scale;
    var marker_box_x = 12; // default right margin of overlay from marker
    var image1,image2,image3,image4,image5,image6,image7,image8,image9;
          
    // markers in arrays
    
    function initialize() {
    
      // set map
      var myLatLng = new google.maps.LatLng(49.910895,15.390794);
      var mapOptions = {
        zoom: 7,
        center: myLatLng,
        mapTypeId: google.maps.MapTypeId.TERRAIN
      };
      map = new google.maps.Map(document.getElementById('map'),mapOptions);
      
      // pois markers      
      var anchorTop = 25;
      var anchorLeft = 25;
      var originTop = 0;
      var originLeft = 0;
      
      image1 = new google.maps.MarkerImage('pcs/marker-logo.png',
        new google.maps.Size(40, 34),
        new google.maps.Point(originLeft,originTop),
        new google.maps.Point(anchorLeft,anchorTop)
      );
      
      image2 = new google.maps.MarkerImage('pcs/marker-info.png',
        new google.maps.Size(40, 34),
        new google.maps.Point(originLeft,originTop),
        new google.maps.Point(anchorLeft,anchorTop)
      );
      
      for (var key in markers_source) {
        addMarker(key,markers_source[key][0],markers_source[key][1],markers_source[key][2]);
      }

      // listener on idle map -> recalculate position all markers
      google.maps.event.addListener(map, 'idle', function() {
        // get map x,y
        topRight = map.getProjection().fromLatLngToPoint(map.getBounds().getNorthEast());
        bottomLeft = map.getProjection().fromLatLngToPoint(map.getBounds().getSouthWest());
        scale = Math.pow(2,map.getZoom());
        
        // get marker x,y
        for (var i = 1; i < markers_list.length; i++) {
          worldPoint = map.getProjection().fromLatLngToPoint(markers_list[i].getPosition());
          markers_xy[i] = new google.maps.Point((worldPoint.x-bottomLeft.x)*scale,(worldPoint.y-topRight.y)*scale);
        }
      });
      
      // hide overlay if move map
      google.maps.event.addListener(map, 'center_changed', function() {
        $("#overlay").hide();
      });
      
      // hide overlay if zoom change
      google.maps.event.addListener(map, 'zoom_changed', function() {
        $("#overlay").hide();
      });
    
    }
    
    // add marker
    function addMarker(id,lat,lon,poiType) {
    
      markers_list[id] = new google.maps.Marker({
        position: new google.maps.LatLng(lat,lon,true),
        map: map,
        icon: eval('image'+poiType)
      });
      
      markers[poiType].push(markers_list[id]);
      
      var showMarkerBubble = new Function("event", "markerBubble("+id+");");
      google.maps.event.addListener(markers_list[id], 'mouseover', showMarkerBubble);
      google.maps.event.addListener(markers_list[id], 'mouseout', function() {
        $("#overlay").hide();
      });
    }
    
    // function for show markers overlay
    function markerBubble(num) {
      
      $("#overlay strong").text(markers_title[num]);
      $("#overlay div").css("background-image", "url('"+markers_pcs[num]+"')");
      
      if (markers_xy[num].x > ($("#map").width()-237)) {
        marker_box_x = -237;
        $("#overlay").css("background-image", "url('pcs/map-buble-left-bg.png')");
        $("#overlay").css("padding-left", "10px");
      } else {
        marker_box_x = 7;
        $("#overlay").css("background-image", "url('pcs/map-buble-right-bg.png')");
        $("#overlay").css("padding-left", "13px");
      }
      $("#overlay").css({
        left:($("#map").position().left + markers_xy[num].x + marker_box_x),
        top:($("#map").position().top + markers_xy[num].y - 51)
      });
      $("#overlay").show();
    }
    
    function setMarkersToMap(sendMap,type) {
      if (!type) {
        for (var key in markers) {
          for (var i = 0; i < markers[key].length; i++) {
            markers[key][i].setMap(sendMap);
          }
        }
      } else {
        for (var i = 0; i < markers[type].length; i++) {
          markers[type][i].setMap(sendMap);
        }
      }
    }
    
    // hide markers
    function clearMarkers(type) {
      if (!cur_type[type]) {
        setMarkersToMap(map,type);
        cur_type[type] = true;
      } else {
        setMarkersToMap(null,type);
        cur_type[type] = false;
      }
    }
    
    // shows markers
    function showOverlays(type) {
      setMarkersToMap(map,type);
    }
    
    // deletes all markers
    function deleteMarkers(type) {
      clearMarkers(type);
      markers[type] = null;
    }
    
    google.maps.event.addDomListener(window, 'load', initialize);