There is a nice set of tutorials about programming with the Marble library. See:

http://techbase.kde.org/Projects/Marble/MarbleCPlusPlus

During a recent task you've created a  tutorial application:

https://google-melange.appspot.com/gci/task/view/google/gci2012/8222202

Please add another page to this set of tutorials which describes in the same detail how the application works. The topic of the tutorial is

Vehicle Tracking

• Explain how the code works (Worker Threads that generate coordinates, Placemark positions defined by the coordinates, updateFeature, etc.)
• Add API doc links to the text
• Show how the code can be compiled
• Point out OSM license requirements

The next task in this series will be about adding Tracks.