GOOGLE EARTH AS A GENERAL 4-D VISUALIZATION APPLICATION

Since its inception, Google Earth (GE) has been used by geoscience educators to aid visualization and understanding of Earth’s surface processes. In order to image the subsurface, the author has developed methods that involve partial or total surface transparency in conjunction with the use of COLLADA models. These methods and models open up possibilities for using the GE application or its browser plug-in version as a general four - dimensional visualization tool in subjects ranging from the sub-microscopic to the galactic scale. Featured sub-disciplines include crystallography, mineralogy, paleontology, structural geology, geophysics, planetary science, and astronomy. For example, the GE terrain may be draped with a hemispheric graticule; after making the terrain 100% transparent, this graticule serves as an interactive 3-D stereographic projection that can be rotated about three axes. Difficult concepts in structural geology and strain analysis are illustrated using the GE time slider control. At the smallest scale, GE illustrates crystal symmetry elements whilst at the largest scale, the Earth-Moon system is animated and our position in the Solar System and Galaxy is illustrated. Students can pause animations and change view angle interactively as desired. Out-of-the-box, GE includes visualizations only for the Earth, Moon, and Mars, but with the aid of COLLADA, models of all planets and moons may be generated. These lack the DEM pyramid structure of the GE 3D terrain but are nevertheless very useful for comparative planetology. The range of possible future applications of GE visualization is exciting. As models are developed, they are being made available to the community via the web site “www.DigitalPlanet.org.”