Dynamic management of geographic data in a virtual environment

In order to achieve true 3D user interaction with geographic information, an interface between a virtual environment system and a geographic information system has been designed and implemented. This VE/GIS interface is based on a loose coupling of the underlying geographic database and the virtual environment system via a dynamic data-translator. This process monitors events initiated by the user in the virtual environment. Based on these events, appropriate queries are generated and sent to the geographic database. On the other hand, the data-translator receives GIS data as a result of queries, and converts these data into appropriate representations for the virtual environment. Moreover, the VE/GIS interface performs data-management tasks in order to efficiently utilize the limited amount of data that can be kept on-line in the virtual environment. To this aim, an object caching mechanism has been devised. The dynamic data-translator supports both explicit and implicit access to the geographic database. These concepts are illustrated in a virtual environment based user interface that provides basic interaction facilities for the intuitive exploration of geographic information. The approach chosen leads to a layered data management scheme where issues related to collaborative VE experiences, such as guaranteed performance, synchronization, concurrent access, and network traffic limitations, can be handled at an appropriate system level.