Marble is a virtual globe which allows the user to choose between the Earth, the Moon, Venus, Mars and other planets to display as a 3-D model. It is free softwareunder the terms of the GNU LGPL , developed by KDE for use on personal computers and smart phones .  It is written in C ++ and uses Qt .
Marble is intended to be very flexible; Beyond its cross-platform design, the core components can easily be integrated into other programs. OpenGL is an open-source, open-source, open- source application . An important user-experience objective being that the application start fairly quickly, it ships with a minimal but useful off-line dataset (5-10MB [ citation needed ] ). 
Contributors-have added carrier for on-line mapping sources Such as OpenStreetMap and the Ability to interpret KML files. Marble also provides road planningcapabilities.  A navigation mode called MarbleToGo was developed as part of Google Summer of Code 2010 .   It was later partially rewritten and renamed to Marble Touch . 
Geothek is a fork of Marble adding a module, pixel maps, and a 3D view. It is developed and used by Austrian publisher Ed. Hölzel as atlas software for classrooms. 
- ^ Jump up to:a b Nienhüser, Dennis. “Introducing Marble Touch” .
- Jump up^ “Chapter 1. Introduction” . KDE.
- Jump up^ Nienhüser, Dennis (2010-07-24). “Worldwide and Offline Routing” . Nienhueser.de . Retrieved 2010-10-25 .
- Jump up^ “Show Student Project” . Google . Retrieved 2010-10-25 .
- Jump up^ Srivastava, Siddharth. “GSoC: MarbleToGo (Navigation Mode)” . Blogspot . Retrieved 2010-10-25 .
- Jump up^ “A look at Geothek 1.1 Digital World Atlas” . 2010-08-07.