Digital terrain editing is one of important research contents in virtual geographical environment and 3D landscape simulation system, which has significant value in digital design practices of city and country, road network, landscape planning, etc. In this article we took the digital terrain based on regular grid as research objectives, oriented to practical application of the city and landscape planning & design, and proposed an interactive digital terrain editing scheme. OpenSceneGraph uses the directed acyclic graph for managing the scene graph, level of detail (LOD) and pagination technique for real-time rendering. Specific processes and related major implementation technology of the terrain interactive editing based on pagination technology was described. Firstly, the target region was selected through the mouse interactive operation combined with ray intersection algorithms. Secondly, the grid data under the region was gotten in the basis of polygon angle sum algorithm. Lastly, the grid elevation of region was assigned a new elevation value by dragging of mouse in the vertical direction. Under the edited region, by the grid method that is used to calculate earthwork volume, it is calculated that the volume of the fills and the excavations. In addition, the trees models were loaded by modeling software of ParaTree, which is researched and developed by our group, and the three-dimensional architectural models were built by the 3DMAX. All the models were loaded into the virtual forest visualization system (VisForest). The virtual town/village landscape in the flattened region was constructed according to user's design idea. The editing function was preliminarily realized, which showed the results of application in urban residential landscape design. This study showed that the digital terrain editing based on regular grid and pagination technology has advantages of simple algorithm, small amount of calculation and easy to realize. What is more, mouse interactive operation can show the editing result in a real-time and intuitional way, and achieve the effect of "what you see is what you get".
LI Jieguang, TANG Liyu, CHEN Chongcheng, ZOU Jie, LIN Ding
. On Interactive Digital Terrain Editing for Landscape Planning & Design and Its Implementation[J]. Journal of Geo-information Science, 2012
, 14(2)
: 179
-186
.
DOI: 10.3724/SP.J.1047.2012.00179
[1] Cao J, Peng X Bo. Research on the design and evaluation of signal coordination control system in urban main road. Proceedings of International Conference on Logistics Engineering and Intelligent Transportation Systems (LEITS). Wuhan, China: IEEE, 2010,1-3.
[2] Bauer O, Robert M. Road database design for velocity profile planning. Proceedings of International Conference on Control Applications. Frankfurt, Germany: IEEE, 2003,1356-1361.
[3] 杨昕, 汤国安, 刘学军,等. 数字地形分析的理论方法与应用[J]. 地理学报, 2009, 64(9): 1058-1070.
[4] 石松, 陈崇成, 王钦敏. 地物仿真及交互可视化编辑工具的设计与实现[J]. 系统仿真学报, 2006, 18(3): 659-684.
[5] Ujang M U, Abdul R A. 3d navigation system for virtual reality based on 3d game engine. Proceedings of International Conference on the International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Beijing, China, 2008,513-518.
[6] Busby J, Parrish Z, Wilson Jeff. Mastering unreal technology: Introduction to level design with unreal engine 3[M]. Sams Publishing, 2009.
[7] Atlan S, Garland M. Interactive multiresolution editing and display of large terrains. Proceedings of Computer Graphics, Wiley Online Library, 2006,211-223.
[8] 王锐, 钱学雷. Openscenegraph三维渲染引擎设计与实践[M]. 北京:清华大学出版社, 2009.
[9] Zhou H, Sun J, Turk G. Terrain synthesis from digital elevation models[J]. IEEE Visualization and Computer Graphics, 2007, 13(4): 834-848.
[10] Strugar F. Continuous distance-dependent level of detail for rendering heightmaps[J]. Journal of Graphics, Gpu, and Game Tools, 2009, 14(4): 57-74.
[11] Duchaineau M, Wolinsky M, Aldrich Charles, et al. Roaming terrain: Real-time optimally adapting meshes. Proceedings of International Conference on Visualization '97, Proceedings. Phoenix, AZ, USA, USA IEEE, 1997,81-88.
[12] Hoppe H. Smooth view-dependent level-of-detail control and its application to terrain rendering. Proceedings of International Conference on Visualization '98 Proceedings. Research Triangle Park,NC,USA IEEE, 1998,35-42.
[13] Losasso F, Hoppe H. Geometry clipmaps: Terrain rendering using nested regular grids. Proceedings of International Conference on ACM Transactions on Graphics (TOG). New York, USA: ACM, 2004,769-776.
[14] Lindstrom P, Pascucci V. Terrain simplification simplified: A general framework for view-dependent out-of\\core visualization[J]. Visualization and Computer Graphics, IEEE Transactions on, 2002, 8(3): 239-254.
[15] 唐勇, 郭栋梁, 吕梦雅. 视点相关的大规模地形内外存调度算法的研究[J]. 系统仿真学报, 2009, 21(8): 2424-2427.
[16] Goswami P, Makhinya M, Bsch J, et al. Scalable parallel out-of-core terrain rendering. Proceedings of International Conference on Eurographics Symposium on Parallel Graphics and Visualization. Norrk?ping, Schweden, 2010,63-71.
[17] 杨旭东, 皮学贤, 李思昆. 基于瓦片四叉树和概要金字塔的地形数据组织与高性能调度[J]. 计算机研究与发展, 2005, 42(增刊): 69-73.
[18] 曹启华, 邓雪情. 基于金字塔模型的规则格网数据可视化交互式编辑[J]. 测绘科学技术学报, 2007, 24(6): 427-431.
[19] Li D, Hu Y S, Meng D Y, et al. The research and implementation of interactive terrain editing and crack elimination. Proceedings of International Conference on Computational Intelligence and Software Engineering. Wuhan, China: IEEE, 2009,1-4.
[20] 汤国安, 刘学军, 房亮, 等. Dem及数字地形分析中尺度问题研究综述[J]. 武汉大学学报(信息科学版), 2006, 31(12): 1059-1066.
[21] Tang L Y, Chen C C, Zou J, et al. OntoPlant: an integrated virtual plant software package for different scale application. Proceedings of 2011 IEEE International Conference on Spatial Data Mining and Geographical Knowledge Services (ICSDM2011) in conjunction with Eighth Beijing International Workshop on Geographical Information Science (BJ-IWGIS 2011), Fuzhou,China: IEEE, 2011, 308-314.
