anchor.diff:  				var systemObject = systemPlusModule.getSystems(index);
   				var isItInPage = isSystemOnPage(systemObject);
   				if(isItInPage){
  +					drawSystem(systemObject, systemObject.ucoord, systemObject.vcoord);
  +				}
  +			}
  +		},
  +		scanVisualSystems: function(){
  +			pageSpace.graphicsInvisible();
  +			flipFlop = 0;
  +			for (var index = 0; index < systemPlusModule.numberSystems(); index++ ){
  +				var systemObject = systemPlusModule.getSystems(index);
  +				var extentU = pageSpace.currentU() + pageSpace.getUextent();
  +				var extentV = pageSpace.currentV() + pageSpace.getVextent();
  +				if(systemObject.ucoord >= pageSpace.currentU() && systemObject.ucoord <= extentU
  +					&& systemObject.vcoord >= pageSpace.currentV() && systemObject.vcoord  <= extentV){
   					drawSystem(systemObject, systemObject.ucoord, systemObject.vcoord);
   				}
   			}
  
positive.code: 							systemId: json.someDetails._systemId,
  							galacticCentre: json.someDetails._distanceToGalaxyCentre
  							});
  				$(json.someDetails.clusterRepList).each(function() {
  					$(this.list).each(function(){
  						console.log("cluster:" + this.string);
  
negative.code:        			console.log("curU:" + curU + " currentV:" + pageSpace.currentV());
         			addToCache.jsonCall(curU, pageSpace.currentV());
         		}
         		drawSystems.scanVisualSystems();
       	});
      	$("#pozU").click(function () { 
         		pageSpace.incrementCurrentU();
         		var curU = pageSpace.currentU() + pageSpace.getUextent();
  