anchor.diff:        restore_state();
       });
       _.each(HeatMap.state.filters, function(filter, index){
  -      $("#controls").append('<div class="title">...</div><h3><span class="count">0</span></h3><div class="options" data-index='+index+'><select class="source"></select><select class="property"></select><select class="measure"></select></div>');
  -    });
  +      if (_.isUndefined(filter.visible)) {
  +        filter.visible = true;
  +      }
  +      checked = '';
  +      if (filter.visible) {
  +        checked='checked ';
  +      }
  +      $("#controls").append('<div class="title">...</div><h3><span class="count">...</span><input class="show" data-index='+index+' type="checkbox" '+checked+'/></h3><div class="options" data-index='+index+'><select class="source"></select><select class="property"></select><select class="measure"></select></div>');
  +    });
  +        
  +    $("#controls input.show").click(function(event) {
  +      HeatMap.state.filters[$(event.target).data("index")].visible = $(event.target).is(':checked');
  +      event.stopPropagation();
  +      localStorage.heatmap = JSON.stringify(HeatMap.state);
  +      display_heatmaps();
  +    }); 
       $("#controls").accordion({
         active: false,
         header: 'h3',
  
positive.code:       {
          HeatMap.instances[index].set('opacity', opacity);
        }
        if (_.isNull(HeatMap.instances[index].map)) {
          HeatMap.instances[index].setMap(map);
        }
      });
    }
  
negative.code:       height: 20px;
        width: 100%;
      }
      div#controls h3 .show {
        top: 2px;
        float: right;
        z-index: 999999;
      }
      div#controls h3 .count {
        color: white;
        font-size: 20px;
  