private boolean setHoustonMap(String mapName){
	  Image mapImage = null;
	  ImageIcon imageIcon;
	  boolean hasFile = false;

	  //for displaying message on the panel.
	  startPanel.appendText(">> Connecting... \n" +
							">> Destination: " + urlStr + " \n");

	  if (url_status){//If URL Internet connection is available, downloads the image.
			try {
					URL url = new URL(urlStr + mapName); //get the Houston map from a remote Server
					imageIcon = new ImageIcon(url);
					mapImage = imageIcon.getImage();
					startPanel.appendText(">> Received Houston city Map... \n");
					hasFile = true;
			}catch(MalformedURLException em) {
					try{
							// If the network connection is not available, get the local image file.
							startPanel.appendText(">> Network resources are unavailable...  \n" +
												  ">> Use the local file instead \n");
							mapImage = getLocalImage(mapName, startPanel);
							hasFile = true;
					}catch(Exception ex){
						printError(startPanel, ex, mapName);
						return false;
					}
			}catch(Exception e){
				printError(startPanel, e, mapName);
			}
	  }else{//If URL connection is not available, use the local image file.
					try{
							// Get the local image instead.
							startPanel.appendText(">> Network resource file are not available...  \n" +
											      ">> Use the local files instead \n");
							mapImage = getLocalImage(mapName, startPanel);
							hasFile = true;
					}catch(Exception exc){
						printError(startPanel, exc, mapName);
					}

	  }

	  if (hasFile){
		  mapCanvas = new MapCanvas(mapImage);
		  return true;
	  }
	  return false;
  }