丝绸之路文物古迹 - 甘肃锁阳城 - 三维建模方法研究 - 蔡磊 - 图文-

1、 收稿日期:2014-01-07。项目来源:国土资源部煤炭资源勘查与综合利用重点实验室自主研究课题资助项目(ZZ2013-3。蔡磊1,2,康荔1,2,代巨鹏2,朱伟2(1.国土资源部 煤炭资源勘查与综合利用重点实验室,陕西 西安 710001;2.陕西省煤田地质局 物探测量队,陕西 西安 710001摘要:以航空摄影和全野外数字化测量等手段,获取丰富的地形地貌数据,再结合多种GIS 数据处理方法获取锁阳城建模数据,通过精细建模和实景贴图技术建立城墙模型,最终在SuperMap 平台下建立三维场景。详细介绍了模型数据获取、模型数据处理和建模的具体方法。关键词:古城墙;三维建模;场景中图分类号:P

2、208 文献标志码:B 文章编号:1672-4623(201404-0105-02锁阳城原名苦峪城,在甘肃省安西县城东南约70 km 的戈壁上,是我国目前保存最为完整的汉唐古城之一,也是古代沙漠化演进过程沧桑变化的典型标本 1。基于甘肃丝绸之路申报世界文化遗产的需要,锁阳城三维建模是必要的。目前三维建模技术日趋成熟,并已经应用到很多方面,对于建模技术方法的研究则主要集中在城市建模和规则地物建模方面2,针对古城墙遗迹的三维建模的研究很少,还没有形成统一且成熟的建模方法。本文针对古迹现状,灵活运用航测相关技术,研究了从模型数据获取到数据处理,再到数据建模的古城墙三维建模方法。1技术路线锁阳城地形凹

3、凸起伏,城墙破损严重,采用常规方法建模实现难度较大。本文首先采用立体测图技术采集地形高程点和城墙特征点;然后在ArcGIS 中对数据进行处理,在3Dmax 中进行地形和城墙建模以及实景贴图;最后将三维地形模型和城墙模型导入到SuperMap 中,建立三维场景。技术路线图如图1。2三维建模根据数据处理方式和建模方法的不同,锁阳城三维建模分为地形建模、城墙建模和其他要素建模3个部分。模型的几何数据综合利用航空摄影测量、内业航空摄影测量工作站通过立体数据采集、全野外数字化散点测量和GIS 数据处理等方法获取。2.1地形建模为更准确、更逼真地反映锁阳城地形,地形建模采用地形模型叠加DOM 的方式。锁阳

4、城影像数据采用无人机获取的高清影像,经正射纠正为DOM。在立体数据采集中,采用2 m×2 m 的采样距离,提取地形高程点。在ArcMap 中展绘高程点,采用克里金法插值出地形栅格,然后采用0.5 m 等高距从地形栅格上提取等值线。将等值线导入到3DMAX 9中,采用地形工具生成地形模型,再与处理好的正射影像DOM 叠加,形成三维地形模型3。2.2城墙建模锁阳城历史悠久,城墙破损严重,为更准确地反映城墙现状,本文利用高清航空摄影影像进行航空摄影测量工作站立体数据采集。采用立体测图方法,绘出城墙的顶底边线,对城墙表面变化较大的地方对照立体影像采集特征线和特征点。为了使一些破坏的城墙区域数

5、据更为精确,又采用了全野外数字化散点测量获取部分数据。在ArcMap 中根据特征线和特征点创建TIN,然后 3D M A X 环境P h o t o s h o p 环境图1锁阳城三维建模技术路线地理空间信息·106·第12卷第4期采用0.2 m间距提取表面等值线,并对等值线作平滑处理。将城墙等值线导入到3DMAX 9中,采用地形工具生成城墙三维模型。为达到与真实城墙逼真的效果,模型建好后要进行实景纹理贴图,贴图应保证其在水平和垂直两个方向上无倾斜,明暗及对比关系合适,颜色与模型周边匹配合理,无树木或其他障碍遮挡4。城墙三维模型如图2所示。 图2城墙三维模型2.3其他地物建

6、模锁阳城中除城墙外,还有许多其他要素,如砖铺路、楼梯、古迹碑等需要进行建模。砖铺路在建模时采用正射影像为底图,矢量化出路的边线,在3Dmax 9中将建好的地形模型调整到俯视状态,然后对矢量图进行映射,从三维地形上提取出砖铺路,最后进行贴图处理。 由于楼梯很窄,在立体测图系统中难以准确采集数据,因此,楼梯的建模数据主要由野外RTK 实测获取。将RTK 测得的数据在Cass 中展点,然后导入到3Dmax 9中进行建模。楼梯模型如图3所示。 图3楼梯三维模型古迹碑建模首先野外量测尺寸,然后在3Dmax 9中进行建模,最后将建立好的模型根据RTK 测得的位置数据放到具体点位。古迹碑模型如图4所示。 图

7、4古迹碑模型2.4模型优化数据量大是三维建模经常遇到的情况。本研究在建模前制定了严格的建模规范,来优化模型结构,降低模型数据量。建模过程中尽量采用最少的面来达到模型表达的效果,能用贴图表现的要避免建模5。建立完成的地物模型,采用3Dmax 中attach 命令将同一地物模型要素合为一个整体,并进行相应命名6。3三维场景建设在3Dmax 中建立的三维模型,通过SuperMap Max Plugin 6R 7插件导出超图空间数据集。采用超图的SCV(大容量模型缓存格式,能很好地解决大模型的显示和运行问题。采用超图插件导出地物模型时,设置模型地理坐标,将模型精确定位到三维场景中的具体位置。Super

8、Map Deskpro 6R 软件具有方便的场景设置工具,能对相机模式、视图模式、场景要素、太阳特效、模型阴影等进行设置。导入到超图三维场景中的模型数据,系统建立默认属性表,可以建立新属性字段,存储模型其他相关信息,“型属结合”,使模型的信息承载力更加强大。三维场景如图5所示。图5锁阳城三维场景参考文献1 李并成.锁阳城遗址及其周围古垦区沙漠化过程考J.丝绸之路,2011(18:27-302 张新利,赵力彬,闫会杰,等.西安世园会三维系统的设计与实现J.测绘通报,2012(11:84-863 张明旺.基于ArcGIS 和3DS Max 的数字厂区三维可视化系统建设与应用研究D.兰州:兰州交通大

9、学,20124 吴延,王晓峰.基于实景图像分色技术的三维全景展示系统研究J.测绘通报,2012(2:71-735 孙悦,鲍泓,马楠,等.中国古建筑虚拟现实系统的数据采集和处理J.北京联合大学学报:自然科学版,2008,22(3:40-446 刘虎,陈汉文.基于3DS MAX 的校园三维模型室内外一体化制作J.地理空间信息,2013,11(2:53-557 北京超图.SuperMap GIS 6R 桌面产品使用手册Z.北京:北京超图软件股份有限公司,2012第一作者简介:蔡磊,硕士,主要从事航空摄影测绘、遥感与地理信息系统应用、数字城市等方面的工作。IVIndex(V ol.12,No.4GEO

10、SPATIAL INFORMATIONapplications of ourselves with the development kit.Key words Android,mobile internet,port management GIS (Page:90Extraction of wind-Wave Parameters Based on GPS Buoyby HUANG Huajuan Abstract This paper presented a combination between GPS receiver and traditional buoy. The GPS buoy

11、 was used to record the wind-wave position information. The wave parameters were calculated by three spectral analysis methods, respectively. The results show that GPS buoy is capable of refl ecting the real situation of wind-wave, meanwhile the experimental results are satisfi ed.Key words GPS buoy

12、,FFT algorithm,COV algorithm, Burg algorithm (Page:94Profile Analysis Method of Urban Underground Pipeline Based on ArcEngine and C#by XIE Han Abstract This paper pointed out the data organization structure of profile analysis based on the distribution of the urban underground pipeline network and c

13、ollected pipeline data. To achieve the function on analyzing transection and vertical section of urban underground pipeline, ArcEngine controls and Visual Studio 2005 software development platform were used as the tools. As a result, the method becomes more convenient to view the cross section of pi

14、peline and spatial relationship amongst all kinds of pipeline, which provides accurate information for decision-making in the scientifi c management of urban underground pipes.Key words GIS, underground pipe, transection, vertical section, cross section (Page:98Research on DLG Graphics Coordinates T

15、ransformationby SUN Liyun Abstract By means of the program based on the pixel coordinate information AutoCAD DLG graphics were extracted, transformation, update, the DLG graphics coordinate was transformed. DLG graphics coordinates transformation would solve the problems that often encountered in da

16、ily work gathered DLG data coordinate system is diff erent from the actual requirement of the diffi culties, especially for conversion to solve everyday small batch DLG graphics coordinate system, low cost, convenient use.Key words AutoCAD graphics, DLG graphics, coordinates, conversion parameters (

17、Page:100Realization of Vegetation Symbols Automatic Sparsing Method in Southern CASS Mapping System by WU Zucheng Abstract This article elaborated the vegetation symbols sparsing method in Southern CASS Mapping System which was based on AutoCAD platform. This method used the AutoCAD's developmen

18、t interface and took the advantage of CASS Mapping System's Built-in functions. Practice proves that vegetation symbols sparsing effi ciency is greatly improved.Key words vegetation, sparsing, AutoCAD, Southern CASS Mapping System (Page:103Research on 3D Modeling of Suoyangcheng as Cultural Reli

19、cs of Silk Road by CAI Lei Abstract This paper got image data by means of aerial photography, and then acquired the terrain data of Suoyangcheng mainly using both the technology of photogrammetry workstation 3D data acquisition and the technology of a full fi eld digital measurement. Combined with a

20、 variety of GIS data processing method to acquire the Suoyangcheng modeling data, the paper built walls model through the technology of fine modeling and real mapping, and established 3D scene based on SuperMap. This article discussed the method of modeling data acquisition, data processing and mode

21、 building in detail.Key words old rampart, 3D modeling, scene (Page:105Comparison Test of Two GPS Control Network Observation Modelsby LI Cunwen Abstract Through organizing and implementing of GPS control network of two observation mode, we made adjustment calculation, results contrast and accuracy

22、check for two models, and summed up the experience for everyone to share.Key words GPS, control network, adjustment (Page:107Research on Information Building of Land Ownership Investigationby CHENG Xiaohe Abstract This paper described land ownership investigation in content, means and process, and s

23、ummarized the working methods. The design and functionality of land ownership management system were discussed. This solution could work effi ciently in production.Key words cadastral survey, land ownership investigation, database, digital management of cadastral archives (Page:109Establishment Meth

24、od and Implementation of 3D Control Network with High Precision of Guangdong Waterway by XU Tian Abstract Taking the Guangdong waterway project for example, an investigation based on GPS, precise leveling and Geoid model, was made on 3D control network in respects of design, data acquisition, baseli

25、ne vector calculation and network adjustment, and method of leveling adjustment. The results show that the precise 3D control network can meet the technical requirements, which lays a solid foundation for Guangdong waterway system.Key words 3D control network, baseline calculation, network adjustmen

26、t, high precision (Page:111Design and Implementation of Land Use Change and Carbon Effect Relations System by LI Haijiang Abstract In this paper, technical routes including the construction of carbon distribution and the monitoring of land use change were taken to study the relations of land use cha

27、nge and Carbon effect. We used ArcEngine components to develop the system platform. Finally, we chose a demonstration zone to test the system application. The result shows that the system is stable and has good popularized value.Key words land use change,Carbon eff ect,relational model,ArcEngine (Pa

28、ge:114Research on Multi-beam Bathymetric Data Compression Based on Python by ZHANG Mingxi Abstract Based on the vertical distance tolerance method ,curve data compression introduced Total Least Squares algorithm for thinning the strand of ping of multi-beam sounding data using Python tools library, implementing the algori