Management And Scheduling Of High Quality 3D Models In Intelligent Terminals Oriented To Indoor Navigation

With the rise of smart phones and the development of digital city, people’s lifestyle has been changed dramatically. The digitalization of city shifted from simple to more detailed, from underground to the surface, from outdoor to indoor. Statistically, there are more than 87% human activities happened indoor(e.g. daily life, work, education, medical care, shopping, and entertainment), or in some closure space like tunnels or mines. Obviously, it is very important to digitalize the indoor space in the field of digital city. However, the technology of indoor positioning has been researched for decade. The combination of indoor modeling, indoor spatial analysis and indoor positioning will have great impact on human activities. Such as shopping guide, schedule of escape route, smart medical care, passenger flow analysis and rescue underground. In contrast, 3D maps have irreplaceable advantages to the traditional ones. They give users “immersive” experiences. The traditional roaming in 3D scene only emphasize the visual effects. And the data contain only geometrical information. These data are created by modelers with various types of 3D modeling software. It hardly to meet the requirement of the generality and the application of digital city.We studied the CityGML standard and the IndoorGML candidate from OGC in details here. They both adopted the OO(object-oriented) method and make classification and description of the properties for those artificial or natural architects and structures which are closely related to human activities. Not only do the data set contain geometrical information, but they also have abundant semantical descriptions. Therefore, not only can the visualization needs be accomplished, but also they can provide complete descriptions for spatial structure and semantic information for many kinds of spatial analysis usage and related applications. The standardization of data can accelerate the development and merge of the industry. We studied:(1)The detailed description of each class and their properties of the standard CityGML Building module;(2)Five LOD description of the standard CityGML Building module.On this basis, the idea of the OO data management of CityGML and the structures of scene graph have been used to study the hierarchy of the directories of our data, we write a descriptive file for our data. Then, we code to read these information and create a certain type of spatial structures to schedule our data. We also use view-frustum culling and occasion culling technologies in the program. These ideas altogether make the client system have good performance on both indoor navigation application and speed. To encode each solo geo-spatial object and manage them separately is a key aspect in the creation of digital city, and efficient data management is also a core problem in the study of 3D GIS. Our study followed these principles and have taken some steps and have certain practical value.