Josh On Design

In previous blogs I introduced the JXMapViewer and JXMapKit, all part of the SwingX-WS project. We're still working on improving these classes and have more good stuff coming. I recently added support for non-rectangular maps, which makes the 1:2 Blue Marble map tile properly. I also added variable size tiles which allows the JXMapKit zoom out further. These are all nice improvements, but don't really matter if mapping isn't important.

I've been blogging about the JXMapViewer for a while now and some of you may wonder: why do I do this? Why does mapping matter? Well, I think it matters a great deal because maps are the way that we interact with the world on any scale larger than a few blocks. Maps let us find out where things are, and visually show information to others. In short; maps are an important way of visualizing information; and that means Java needs great support for mapping.

The problem, however, is that we currently only have access to some NASA imagery, which some people feel isn't very useful. Well, I have two answers to that:

Doing cool things with NASA's Blue Marble images

The best way to show people that maps can be pretty and useful is simply to do it. Here is a screenshot of a JXMapKit that has been tricked out with Painters and the Timing Framework. It is a simple travelog showing various points on the globe that I have visited, along with some descriptive text. The screenshot is pretty but you really need to see it live to get a feel for how the animations and rollovers work.

Fancy JXMapViewerApplet. Run it live

Though the data in this demo is hard coded it could easily be specified using applet parameters. This would let non-programmers embed it in their webpages, showing their own travelogs! All of the effects you see here were done using stock Painters and the Timing Framework, all part of Swing Labs.

But what about the second part....

Getting a new free map source: Open Street Maps

We can now view street maps from the Open Street Maps project! If you haven't heard of this project before you should really check it out. It is a map put together by individuals tagging and uploading GPS traces to a shared database. They only have a few cities so far (mostly in Europe) but they are growing every day and could use more help. A simply amazing project! Here's a screenshot:

JXMapViewer showing Open Street Maps of London

To get Open Street Maps in your own application use this provider:

        final int max = 17;
        TileFactoryInfo info = new TileFactoryInfo(0,max,max,
                256, true, true,
                "http://tile.openstreetmap.org",
                "x","y","z") {
 ��          public String getTileUrl(int x, int y, int zoom) {
                zoom = max-zoom;
                return = this.baseURL +"/"+zoom+"/"+x+"/"+y+".png";
            }
        };
        info.setDefaultZoomLevel(1);
        
        TileFactory tf = new DefaultTileFactory(info);
        JXMapKit map = new JXMapKit();
        map.setTileFactory(tf);
        map.setCenterPosition(new GeoPosition(51,30,25,0,7,39)); // the center of London

And that's it. Street maps in your own app.

But of course, the best thing to convince others that the JXMapViewer is worthwhile is quite simple: get people to build more apps! So lets build some more. If you have any application you've written using the JXMapViewer please email me or post it here. We'll highlight it on the SwingX-WS webpage and try to get it into the JavaDesktop.org project spotlight.

Thanks everyone!

- Josh

Postscript: here is the source to both the applet demo and the OSM tile provider. The required jars are included.