Virtual globes for 4D environmental analysis

Abstract

Virtual globes were initially released as effective and intuitive tools to view satellite and aerial photos directly superimposed on the 3D modeling of the globe. The constant update of increasingly accurate and detailed images and the ability to customize the content through the direct mapping on the globe of any geographically localized phenomenon (physical, environmental, social, etc.) have increased not only the common and popular use of virtual globes but has also offered great opportunities for geographical representation and analysis in science. The paper presents solutions we implemented for environmental purposes; in particular, three different viewers for 4D environmental variables (3D location of the variable at different times) using an open-source virtual globe developed by NASA (NASA World Wind). The third solution presented is the most innovative one and uses a “doxel-based” approach for modeling environmental variable distributions. The choice of World Wind is due to its code openness and hence the possibility for both customizing and extending its functionality. The characteristic of being written in Java makes it a platform-independent program (viewer directly executable on different operation systems) and accessible by simple web-browsers (like applet or via Java Web Start technology). In detail, we present solutions that can be directly implemented using existing software tools and an innovative solution specifically developed.