Virtual globe

A virtual globe is a three-dimensional (3D) software model or representation of the Earth or another world. A virtual globe provides the user with the ability to freely move around in the virtual environment by changing the viewing angle and position. Compared to a conventional globe, virtual globes have the additional capability of representing many different views on the surface of the Earth. These views may be of geographical features, man-made features such as roads and buildings, or abstract representations of demographic quantities such as population.

On November 20, 1997, Microsoft released an offline virtual globe in the form of Encarta Virtual Globe 98, followed by Cosmi's 3D World Atlas in 1999. The first widely publicized online virtual globes were NASA World Wind (released in mid-2004) and Google Earth (mid-2005). NOAA released its virtual globe, Science On A Sphere (SOS) Explorer, in September 2015.

Types

Virtual globes may be used for study or navigation (by connecting to a GPS device) and their design varies considerably according to their purpose. Those wishing to portray a visually accurate representation of the Earth often use satellite image servers and are capable not only of rotation but also zooming and sometimes horizon tilting. Very often such virtual globes aim to provide as true a representation of the World as is possible with worldwide coverage up to a very detailed level. When this is the case the interface often has the option of providing simplified graphical overlays to highlight man-made features since these are not necessarily obvious from a photographic aerial view. The other issue raised by such detail available is that of security with some governments having raised concerns about the ease of access to detailed views of sensitive locations such as airports and military bases.