Creating a Simple Map Application

The application example given in this section is the JViews Maps application provided in <installdir> /jviews-maps/samples/buildmap/index.html as part of the  JViews Maps demonstration software.

The application:

• Creates a map GUI.

• Loads a shape file, an image file (a raster), and two data sources.

To create the application:

1. Import the following Java™ packages and classes:

    

   import ilog.views.*;

   import ilog.views.maps.*;

   import ilog.views.maps.beans.*;

   import ilog.views.maps.datasource.*;

   import ilog.views.maps.format.image.IlvRasterBasicImageReader;

   import ilog.views.maps.graphic.style.IlvPolylineStyle;

   import ilog.views.maps.raster.datasource.IlvRasterDataSourceFactory;

   import ilog.views.maps.srs.coordsys.IlvCoordinateSystem;

   import ilog.views.maps.srs.coordsys.IlvGeographicCoordinateSystem;

   import ilog.views.swing.IlvJManagerViewControlBar;

   import ilog.views.swing.IlvJScrollManagerView;

   import java.awt.*;

   import java.beans.PropertyChangeEvent;

   import java.beans.PropertyChangeListener;

   import java.io.File;

   import java.net.URL;

   import javax.swing.JFrame;

   import javax.swing.JTabbedPane;

2. Declare the public class BuildMapDemo, which defines the basic building blocks of the Map Builder:

    

   public class BuildMapDemo extends JFrame {

    

       IlvManagerView view;// Map View

       IlvJScrollManagerView viewScroll;// scroll around the Map View

       IlvJManagerViewControlBar viewToolbar; // zoom & selection toolbar

       IlvLayerTreePanel layerTreePanel = new IlvLayerTreePanel(); // layer

          visibility and properties control

       IlvJCoordinateSystemEditorPanel csPanel;// coordinate system choice.

       IlvJMouseCoordinateViewer locator;// coordinate information

3. Create a main frame and set it to exit when the Close button is pressed:

    

   public BuildMapDemo() {

   super();

   setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

4. Create the main components of this example and set them up:

    

   view=new IlvManagerView();

   view.setManager(new IlvGrapher());

   viewScroll=new IlvJScrollManagerView(view);

   viewToolbar = new IlvJManagerViewControlBar();

   csPanel=new IlvJCoordinateSystemEditorPanel();

   viewToolbar.setView(view);

   locator=new IlvJMouseCoordinateViewer();

   locator.setView(view);

   viewToolbar.add(locator);

   view.setKeepingAspectRatio(true);

   view.setBackground(new Color(80, 180, 240));

   view.setAntialiasing(false);

   view.setSize(new Dimension(900, 450));

   viewScroll.setPreferredSize(view.getSize());

   layerTreePanel.setView(view);

5. Georeference the view:

    

   view.getManager().setNamedProperty(new

   IlvCoordinateSystemProperty(IlvGeographicCoordinateSystem.WGS84));

6. Set up the Coordinate System panel to change projection according to panel selection and to reload the map data:

    

   csPanel.setCoordinateSystem(IlvCoordinateSystemProperty.GetCoordinateSystem

      (view.getManager()));

   csPanel.addCoordinateSystemChangeListener(new PropertyChangeListener(){

      public void propertyChange(PropertyChangeEvent evt) {

         IlvCoordinateSystem system = (IlvCoordinateSystem) evt.getNewValue();

   view.getManager().setNamedProperty(new IlvCoordinateSystemProperty(system));

   clearManager();

   loadData();

   }

   });

7. Build the map and configure the main window:

    

   loadData();

   getContentPane().add(viewToolbar,BorderLayout.NORTH);

   getContentPane().add(viewScroll,BorderLayout.CENTER);

   JTabbedPane tabPane=new JTabbedPane();

   tabPane.addTab("Map layers",layerTreePanel);

   tabPane.addTab("Coordinate System",csPanel);

   getContentPane().add(tabPane,BorderLayout.LINE_START);

   getContentPane().add(locator,BorderLayout.SOUTH);

   }

8. Load the sample map data into the application:

    

   private void loadData() {

      URL shpFile = findURL("data/world.shp");

      URL gifFile = findURL("data/world.gif");

      try {

         // Create a data source for the shape file.

        IlvShapeDataSource shpDataSource = new

           IlvShapeDataSource(shpFile.getFile(), true);

        shpDataSource.setCoordinateSystem(IlvGeographicCoordinateSystem.WGS84);

        // Create a raster reader for the .gif file (necessary to create the

           datasource that follows).

        IlvRasterBasicImageReader imageReader = new

           IlvRasterBasicImageReader();

        imageReader.loadImage(gifFile.getFile());

        // Georeference this image (it covers the whole earth).

        imageReader.setImageBounds(0,-Math.PI,Math.PI/2,Math.PI,-Math.PI/2);

        // Create a datasource for the .gif file.

           IlvMapDataSource imageDataSource =

              IlvRasterDataSourceFactory.buildImageDataSource(

              view.getManager(),imageReader,true,true,true,null);

        // Insert it in the data source tree of the manager.

        IlvMapDataSourceModel dataSourceModel =

           IlvMapDataSourceProperty.GetMapDataSourceModel(view.getManager());

        dataSourceModel.insert(shpDataSource);

        dataSourceModel.insert(imageDataSource);

        // Start reading the model (recursively start all data sources of this

           model).

        dataSourceModel.start();

        // Get the shape map layer used to display the data source.

        IlvMapLayer shpLayer = shpDataSource.getInsertionLayer();

        shpLayer.setName("ESRI layer (world.shp)");

        IlvMapLayer imageLayer = imageDataSource.getInsertionLayer();

        // Insert it in the Map layer tree of the manager.

        IlvMapLayerTreeModel ltm =

           IlvMapLayerTreeProperty.GetMapLayerTreeModel(view.getManager());

        ltm.addChild(null, shpLayer);

        ltm.addChild(null, imageLayer);

        // Set up the shape layer style.

        shpLayer.getStyle().setAttribute(IlvPolylineStyle.FOREGROUND,Color.

           black);

        shpLayer.getStyle().setAttribute(IlvPolylineStyle.BACKGROUND,new

           Color(1,1,1,0.25f));

        imageLayer.setName("Image layer (world.gif)");

     } catch (Exception e1) {

        e1.printStackTrace();

   }

9. Fit the data source to the size of the application view:

    

   view.fitTransformerToContent();

   view.repaint();

   }

10. Write the main method:

     

    static public void main(String args[]) {

      javax.swing.SwingUtilities.invokeLater(

        new Runnable() {

          public void run() {

            final JFrame frame = new BuildMapDemo();

            frame.setTitle("Simple map building demo");

            frame.pack();

            frame.setVisible(true);

        }

      );

    }

11. Remove all the layers from the manager and clear the associated model when the coordinate system changes:

     

    private void clearManager() {

       IlvManager manager = view.getManager();

       IlvMapLayerTreeModel model =

          IlvMapLayerTreeProperty.GetMapLayerTreeModel(manager);

       model.clearAllObjects();

       while (manager.getLayersCount() > 0) {

         IlvManagerLayer layer = manager.getManagerLayer(0);

         manager.removeLayer(0, false);

       }

       manager.removeNamedProperty(IlvMapLayerTreeProperty.NAME);

       manager.removeNamedProperty(IlvMapDataSourceProperty.NAME);

       manager.removeNamedProperty(IlvAreasOfInterestProperty.NAME);

       }

    }