function removeChains()
{
	for (var i = 0; i < markerGroups["chains"].length; i++) {
       		


       		var marker = markerGroups["chains"][i];
        	if (marker.isHidden()) 
        	{
          		//polyline.show();
        	} 
        	else 
        	{
          		marker.hide();
          		//polyline.remove();
        	}
        }

}

function refreshChains()
{
	var bounds1 = new GLatLngBounds();
	var bounds2 = new GLatLngBounds();
	
	

	for (var i = 0; i < markerGroups["chains"].length; i++) {
      
       		var marker = markerGroups["chains"][i];
          	marker.show();
        }

}


function drawChains()
{

	randomNum = Math.floor(Math.random()*10000000);

	//** this works
	//var ChainUrl = "./data/chain.xml?" + randomNum.toString();
	var ChainUrl = "http://map.commuteview.net/chainkml/chainsProxy.aspx?" + randomNum.toString();
	




	var request = GXmlHttp.create();
	request.open("GET", ChainUrl, true);

      	request.onreadystatechange = function() {

		if (request.readyState == 4) {
		
			var xmlDoc = request.responseXML;
			var markers = xmlDoc.documentElement.getElementsByTagName("Section");

			for (var i = 0; i < markers.length; i++) {

				var controlLevel = markers[i].getElementsByTagName("Control_Level")[0].childNodes[0].nodeValue;

				if(controlLevel == "R-1" || controlLevel == "r1" || controlLevel == "R-2" || controlLevel == "r2" || controlLevel == "R-3" || controlLevel == "r3" || controlLevel == "rc" || controlLevel == "pe")
				{
					var kmlFile = markers[i].getElementsByTagName("Kml_Filename")[0].childNodes[0].nodeValue;
					var geoXml; 

					
					//if(controlLevel == "R-1" || controlLevel == "r1")
					//	var ChainUrl = "http://map.commuteview.net/chainkml/r1/" + kmlFile;
					
					//else if(controlLevel == "R-2" || controlLevel == "r2")
					//	var ChainUrl = "http://map.commuteview.net/chainkml/r2/" + kmlFile;
					
					//else if(controlLevel == "R-3" || controlLevel == "r3")
					//	var ChainUrl = "http://map.commuteview.net/chainkml/r3/" + kmlFile;
					
					var ChainUrl = "http://map.commuteview.net/chainkml/" + controlLevel + "/" + kmlFile;
					
					//alert(kmlFile);
					
					geoXml = new GGeoXml(ChainUrl);
					markerGroups["chains"].push(geoXml);
					map.addOverlay(geoXml);
				}

			}
		}
      	}

      	request.send(null);







}