Marble/MarbleCPlusPlus

Editing Projects/Marble/MarbleCPlusPlus

Hello Marble

Tutorial Series	Marble C++ Tutorial
Previous	C++, Qt
What's Next	Tutorial 2 - MarbleWidget: Changing basic map properties
Further Reading	n/a

Hello Marble!

The API of the Marble library allows for a very easy integration of a map widget into your application.

Let's prove that with a tiny Hello world-like example: Qt beginners might want to have a look at the Qt Widgets Tutorial to learn more about the details of the code. But this is probably not necessary. For a start we just create a QApplication object and a MarbleWidget object which serves as a window. By default the MarbleWidget uses the Atlas map theme. However for our first example we choose to display streets. So we set the maptheme id to OpenStreetMap. Then we call QWidget::show() to show the map widget and we call QApplication::exec() to start the application's event loop. That's all!

#include <QtGui/QApplication>
#include <marble/MarbleWidget.h>

using namespace Marble;

int main(int argc, char** argv)
{
    QApplication app(argc,argv);

    // Create a Marble QWidget without a parent
    MarbleWidget *mapWidget = new MarbleWidget();

    // Load the OpenStreetMap map
    mapWidget->setMapThemeId("earth/openstreetmap/openstreetmap.dgml");

    mapWidget->show();

    return app.exec();
}

Copy and paste the code above into a text editor. Then save it as my_marble.cpp and compile it by entering the following command on the command line:

 g++ -I /usr/include/qt4/ -o my_marble my_marble.cpp -lmarblewidget -lQtGui

If things go fine, execute ./my_marble and you end up with a fully usable OpenStreetMap application:

Tip

Here's a little checklist to tackle some problems that might arise when compiling the code above:

You need Qt and Marble development packages (or comparable git installations)
If Qt headers are not installed in /usr/include/qt4 on your system, change the path in the g++ call above accordingly.
Likewise, add -I /path/to/marble/headers if they're not to be found in /usr/include

Note

If you provide maps in your application please check the Terms of Use of the map material. The map material that is shipped with Marble is licensed in the spirit of Free Software. This usually means at least that the authors should be credited and that the license is mentioned. E.g. for OpenStreetMap the license is CC-BY-SA. Other map data shipped with Marble is either public domain or licensed in the spirit of the BSD license.