Neotropic SAS

Using Open Street Maps in your Netbeans Application

Currently we’re working on the module to support outside plant management in Kuwaiba, so it’s necessary to integrate GIS capabilities into the system. The general architecture would include the following components:

GIS views support: general architecture

The new blocks are the tile caching server and the map provider. The bare maps are extracted from the latter and the tiles are cached into the former. The business specific layers  such as pipelines, conduits, poles, distribution frames or cabinets are requested to the webservice interface, which returns an XML document describing the coordinates of those elements as well as other complementary information (labels, areas, etc).

In the present tutorial I will show you a way to place maps on your Netbeans Platform application and to put layers over those maps using the Visual Library.

Requirements

• Netbeans IDE
• SwingX core
• SwingX-ws

The How-to

JXMapviewer is a component included in the SwingX library (a set of components to extend the Swing API). It’s a subclass of JComponent and can be embedded into any Java Desktop application. It offers many features such as showing waypoints and rendering layers over a map. Having said that, you have to wonder why using the Visual Library if you can do almost everything with JXMapViewer, but the answer is pretty simple: The Visual Library lets you interact naturally with the vector elements in a GIS scenario. This is, you can put nodes and edges over the map and play with lookups and property sheets (for example) or add actions flawlessly to these elements. Accomplishing  this with only JXMapViewer and Java 2D API is significantly harder. The sources for this tutorial can be downloaded  from here.

1. Download the SwingX core jar from here.
2. The SwingX-ws binaries seem to be gone, so you can build them by yourself. Just get a subversion client and checkout the code
   svn checkout https://svn.java.net/svn/swingx-ws~svn/trunk
   Create a project from existing sources, pointing to the code you just downloaded (File->New Project->Java->Java project with Existing Sources). Expand the tree and right click on the “Libraries” node. Select “Add JAR/Folder”. Select the jar you downloaded in the previous step. Now you should be ready to compile the project. The resulting binary will be located within the “dist” directory, inside the project folder.
3. Create a Netbeans Plaform Project (File->New Project->Netbeans Modules->Netbeans Platform Application)
4. Create a module. In our case, it will be called “MainModule”
   

   Creating a new module

5. Add a new TopComponent to your module (Right click on the module -> New -> Window) Select the “editor” window mode. Note: Make sure you set its layout to BorderLayout (Thanks, Javier!)
   

   New TopComponent

6. Enable de Visual Library. For this, Right click on the MapsProject project, select libraries, scroll down to “platform”, expand that node and check “Visual Libray”
   

   Enabling the Visual Library

7. Add the SwingX jars. For this, right click on the MainModule module, select “Properties” and then “Libraries”. Go to the “Wrapped JARs” tab and by pressing the “Add JAR” button, add the libraries obtained through the steps 1 and 2.
   

   Adding the SwingX libraries

8. Add the Visual Libray API to the module dependencies:
   

   Visual Library as module depedency

9. Now we’re ready to code. What we’re going to do is to add a scene  and put three layers on it: One to contain the map, another to contain the routes and another to hold the  nodes. We will also set a custom overlay painter so the route coordinates are recalculated every time. Take into account that is required to translate the geographic position (polar) to Cartesian coordinates within the scene viewport. It’s important to point out that the ComponentWidget containing the map size can’t match the container size using a layout, so we have to do it manually and that’s what the updateBounds() method is for. Let’s take a look at the scene constructor:
   
...
//The layers
mapLayer = new LayerWidget(this);
routesLayer = new LayerWidget(this);
nodesLayer = new LayerWidget(this);
addChild(mapLayer);
addChild(routesLayer);
addChild(nodesLayer);//The map. We use JXMapKit instead of JXMapViewer because the kit includes the zoom slider, a satellite view and
   //and a JXMapViewer
   myMap = new JXMapKit();
   myMap.setDefaultProvider(JXMapKit.DefaultProviders.OpenStreetMaps);
   myMap.setCenterPosition(mapCenter);
   myMap.getMainMap().setZoom(2);
   mapWidget = new ComponentWidget(this, myMap);
   mapLayer.addChild(mapWidget);//The nodes
   icnw1 = (IconNodeWidget)addNode(“widget1″);
   icnw2 = (IconNodeWidget)addNode(“widget2″);
   icnw1.setImage(ImageUtilities.loadImage(GENERIC_ICON_PATH));
   icnw2.setImage(ImageUtilities.loadImage(GENERIC_ICON_PATH));//The route
   conWidget = (ConnectionWidget)addEdge(“con1″);
   conWidget.setControlPointShape(PointShape.SQUARE_FILLED_BIG);
   conWidget.setLineColor(Color.RED);
   conWidget.setStroke(new BasicStroke(2));myMap.getMainMap().setOverlayPainter(new Painter() {

   @Override
   public void paint(Graphics2D gd, Object t, int i, int i1) {
   Rectangle realViewport = myMap.getMainMap().getViewportBounds();
   Point2D endpointA2D = myMap.getMainMap().getTileFactory().geoToPixel(endpointA, myMap.getMainMap().getZoom());
   Point2D endpointB2D = myMap.getMainMap().getTileFactory().geoToPixel(endpointB, myMap.getMainMap().getZoom());
   icnw1.setPreferredLocation(new Point((int)endpointA2D.getX()-realViewport.x – ICON_RADIUS,(int)endpointA2D.getY()-realViewport.y – ICON_RADIUS));
   icnw2.setPreferredLocation(new Point((int)endpointB2D.getX()-realViewport.x – ICON_RADIUS,(int)endpointB2D.getY()-realViewport.y – ICON_RADIUS));
   List<Point> controlPoints2D = new ArrayList<Point>();
   controlPoints2D.add(new Point((int)endpointA2D.getX()-realViewport.x,(int)endpointA2D.getY()-realViewport.y));
   for (GeoPosition controlPoint : controPoints){
   Point2D controlPoint2D = myMap.getMainMap().getTileFactory().geoToPixel(controlPoint, myMap.getMainMap().getZoom());
   controlPoints2D.add(new Point((int)controlPoint2D.getX()-realViewport.x,(int)controlPoint2D.getY()-realViewport.y ));
   }

   controlPoints2D.add(new Point((int)endpointB2D.getX()-realViewport.x,(int)endpointB2D.getY()-realViewport.y));

   //For some reason, it’s necessary to set the anchors everytime. It’s a rendering issue
   setAnchors();
   conWidget.setControlPoints(controlPoints2D, true);
   validate();
   }
   });

   //If this is not done, an IllegalStateException will be raised when reositioning the conection widget
   routesLayer.bringToFront();
   nodesLayer.bringToFront();
   …

10. Now we put some code to the TopComponent to include the scene. We have to override the paint(Graphics g) method to update the map bounds.  Let’s take a look at the TopComponent constructor:
    
...
initComponents();
setName(NbBundle.getMessage(GISTopComponent.class, "CTL_GISTopComponent"));
setToolTipText(NbBundle.getMessage(GISTopComponent.class, "HINT_GISTopComponent"));
myScene = new MapScene();
add(myScene.createView());
myScene.updateBounds();
...

11. Click on the image to enlarge.

Result

Note: You need a working internet connection in order to run the project flawlessly. Otherwise you’ll get and UnknownHostException.

Download the code here.

References

•  Building Maps into Your Swing Application with the JXMapViewer
• Mapping Mashups with the JXMapViewer
• Track’n'Mash: Openstreetmap Karten in Java/Swing mit JXMapViewer