ADAYA: A SIMPLE AND EFFICIENT OPEN SOURCE VIRTUAL GLOBE
During the last years, several open source virtual globes have appeared in the geospatial community and some of these have become a reference for users and developers. Most of these include many features that are thought for the final user that is normally interested in a broad range of functionalities. However, this could be a drawback for some developers and researchers that could be interested in implementing a concrete method, avoiding the burden of managing many complex components. Our software is a new open source virtual globe that is simple and efficient and could serve as a testing environment for new methods in the geospatial sciences and computer graphics. We have developed a client application in C++. The kernel of the system consists of a series of classes that implement a multiresolution model for representing the terrain at different levels of detail; several threads that are in charge of downloading the textures and meshes from remote servers; and the graphic rendering stuff that is executed in a high priority thread. The mesh and textures are stored in a quad tree at different levels of resolution. We have implemented a view-dependent level of detail strategy that loads and unloads the regular meshes depending on the position of the cameras. The application downloads the mesh and texture data from remote servers, via the Web Map Service standard protocol. The visualization of very large terrain databases requires an out-of-core strategy to store and retrieve the terrain data from a secondary storage. The application executes several threads to manage this data and establish multiple connections to accelerate the transit of information. In future releases, the software will include, in separate modules, the most important standards from the Open Spatial Consortium and other basic capabilities.
Javier Sánchez - University of Las Palmas of Gran Canaria
Agustín Trujillo - University of Las Palmas of Gran Canaria
Agustín Salgado - University of Las Palmas of Gran Canaria