function getMarkerbyOverlayID(markerid,overlayid){
	for (var i = 0 ; i < gMarkers.length ; i++){  // go through all markers 
	    if(gMarkers[i].markerid == markerid && gMarkers[i].overlay == overlayid){ 
			return gMarkers[i];
		} 
	}  
}
function getMarkerbyTypeID(markerid,type){	
	for (var i = 0 ; i < gMarkers.length ; i++){  // go through all markers 
	      if(gMarkers[i].markerid == markerid && gMarkers[i].searchtype == type){ 
	      	return gMarkers[i];
		} 
	}  
	return null;
}
function hasMarkersbyType(type){	
	for (var i = 0 ; i < gMarkers.length ; i++){  // go through all markers 
	      if(gMarkers[i].searchtype == type){ 
	      	return true
		} 
	}  
	return false;
}
function hasMarkersbyOverlay(overlayid){	
	for (var i = 0 ; i < gMarkers.length ; i++){  // go through all markers 
	      if(gMarkers[i].overlay == overlayid){ 
	      	return true
		} 
	}  
	return false;
}