CESIUM—A VIRTUAL GLOBE WITH STRONG POTENTIAL APPLICATIONS IN GEOSCIENCE EDUCATION

The efficacy of virtual globes such as Google Earth for enhancing geospatial visualization skills has been well documented in the education research literature. As part of Project GEODE (below) we are building a library of virtual globe-based resources for use both in-person and in online courses. These include virtual field tours enhanced with georeferenced gigapixel imagery and virtual specimens, and interactives based on the Google Earth web browser plugin and application program interface (API). Because of security concerns unrelated to Google Earth, browser plugins in general are being deprecated. Google have promised a plugin-free API some time in the future but are concentrating in the short term on modernizing the Google Earth desktop application. Therefore, we are exploring the potential of a new, plugin-free, JavaScript-based, virtual globe for modern web browsers called Cesium (http://www.cesiumjs.org).

Cesium’s speed in loading surface imagery is generally slower than Google Earth (no one can compete with the Google map tile servers that share refresh tasks over tens of thousands of parallel processors), however once you get used to waiting an extra second or two for image delivery, Cesium has significant advantages for geoscience applications. Chief among these is the ability to punch a hole in the surface and place 3D models and data representations in the sub-surface. Such holes can range from the depth of a water well to an octant or quadrant of the globe.

Other researchers have created a truly 4-dimensional virtual globe based on Chris Scotese’s paleogeography and have built powerful tectonic and geophysical tools such as GPlates based on the Cesium globe. We have successfully draped geological maps and transferred content such as GigaPans and virtual specimens to Cesium. This requires porting COLLADA models to glTF, the new standard for WebGL models. An online tool is available to automate the process, although we have found limitations in the file size that can be handled. Sample classroom activities using the Cesium virtual globe will be demonstrated.

Supported by NSF DUE 1323419: "Google Earth for Onsite and Distance Education."