Collaborative 3D Modeling of Large-Scale Virtual Geographic Environment

Author(s):  
Weijun Yang ◽  
Jianhua Gong ◽  
Chuanwen Hu ◽  
Weixing Wang
2019 ◽  
Vol 8 (10) ◽  
pp. 428 ◽  
Author(s):  
Bingchuan Jiang ◽  
Liheng Tan ◽  
Yan Ren ◽  
Feng Li

The core of intelligent virtual geographical environments (VGEs) is the formal expression of geographic knowledge. Its purpose is to transform the data, information, and scenes of a virtual geographic environment into “knowledge” that can be recognized by computer, so that the computer can understand the virtual geographic environment more easily. A geographic knowledge graph (GeoKG) is a large-scale semantic web that stores geographical knowledge in a structured form. Based on a geographic knowledge base and a geospatial database, intelligent interactions with virtual geographical environments can be realized by natural language question answering, entity links, and so on. In this paper, a knowledge-enhanced Virtual geographical environments service framework is proposed. We construct a multi-level semantic parsing model and an enhanced GeoKG for structured geographic information data, such as digital maps, 3D virtual scenes, and unstructured information data. Based on the GeoKG, we propose a bilateral LSTM-CRF (long short-term memory- conditional random field) model to achieve natural language question answering for VGEs and conduct experiments on the method. The results prove that the method of intelligent interaction based on the knowledge graph can bridge the distance between people and virtual environments.


Minerals ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 271 ◽  
Author(s):  
Michael Zhdanov ◽  
Fouzan Alfouzan ◽  
Leif Cox ◽  
Abdulrahman Alotaibi ◽  
Mazen Alyousif ◽  
...  

2013 ◽  
Vol 307 ◽  
pp. 464-469
Author(s):  
Bing Chuan Jiang ◽  
Xiong You ◽  
Qing Xia ◽  
Wei Zhang

The expression of virtual geographic environment is based on the surface modeling, such as three-dimensional terrain modeling and rendering most of which are based on the polygon grid and 2D textured. In the expression of extreme terrain, such as caves, cliffs, canyons it seems powerless. However, the voxel-based terrain modeling has been more useful than polygon modeling expression in the field of real-time terrain deformation, extreme terrain simulation and geographic process expression. Furthermore, virtual geographic environment based on the traditional surface model is difficult to realistically simulate the real world which is volumetric. This paper analyzes the trends of the geographical environment representation, and discusses the typical voxel-based applications in natural phenomena simulation, terrain modeling and spatial process analysis. It provides the references for the integrative representation of the unified voxel and surface model, and for the construction of virtual geographic environment unified platform.


2018 ◽  
Vol 7 (9) ◽  
pp. 356 ◽  
Author(s):  
Jia Li ◽  
Yongxiang Yao ◽  
Ping Duan ◽  
Yun Chen ◽  
Shuang Li ◽  
...  

Oblique imagery obtained from an Unmanned Aerial Vehicle (UAV) has been widely applied to large-scale three-dimensional (3D) reconstruction; however, the problems of partially missing model details caused by such factors as occlusion, distortion, and airflow, are still not well resolved. In this paper, a loop-shooting-aided technology is used to solve the problem of details loss in the 3D model. The use of loop-shooting technology can effectively compensate for losses caused by occlusion, distortion, or airflow during UAV flight and enhance the 3D model details in large scene- modeling applications. Applying this technology involves two key steps. First, based on the 3D modeling construction process, the missing details of the modeling scene are found. Second, using loop-shooting image sets as the data source, incremental iterative fitting based on aerotriangulation theory is used to compensate for the missing details in the 3D model. The experimental data used in this paper were collected from Yunnan Normal University, Chenggong District, Kunming City, Yunnan Province, China. The experiments demonstrate that loop-shooting significantly improves the aerotriangulation accuracy and effectively compensates for defects during 3D large-scale model reconstruction. In standard-scale distance tests, the average relative accuracy of our modeling algorithm reached 99.87% and achieved good results. Therefore, this technique not only optimizes the model accuracy and ensures model integrity, but also simplifies the process of refining the 3D model. This study can be useful as a reference and as scientific guidance in large-scale stereo measurements, cultural heritage protection, and smart city construction.


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