Virtual geographic environment database design and collaboration

As a development in geography and geographic information science, virtual geographic environment (VGE) embodies abstract concepts, makes people immerge in the virtual world, studies the geography problems, and carries out geographic examinations. VGE has plenty of multi-kinds of data, such as digital elevation model data, data of objects under and on the Earth surface, image data, audio data, video data, avatar movement data, interaction data, environment data, and so on. VGE data can be classified as dynamic data and static data according to data changing. At the same time, VGE data can also be classified into global data and local data with an eye to data using range. According to VGE data attributes and its classifications, we design a VGE database, which fits VGE\´s three main contents: virtual geographic environment construction, entities construction and the interaction between environment and entities. There has a global database to store global data and several local databases to store their region data. The database is also distributed, so we study a method and an architecture to solve the database collaboration. We call the method "pre-data-preparing". In the end, we give an example of DEM database collaboration of GuanTing lake located in the west of Beijing.