基于SketchUp的三维地貌建模技术

1、地理空间信息GEOSPATIAL INFORMATION2013年2月第11卷第1期Feb.,2013V ol.11,No.1 中图分类号: P208 文献标志码:B 文章编号:1672-4623(201301-0064-03收稿日期:2012-07-27。项目来源:教育部人文社会科学研究一般项目(11YJC630202;辽宁省教育厅创新团队项目(WT2010031。基于SketchUp 的三维地貌建模技术杜 研1,王方雄1,王 博1(1.辽宁师范大学 自然地理与空间信息科学辽宁省重点实验室 城市与环境学院,辽宁 大连 116029摘 要:提出了三维地貌模型的逻辑结构,阐述了基于三维建模工具S

2、ketchUp 的三维地貌建模流程,介绍了基于等高线和基于高程点的2种三维地貌建模技术;并以大连生态科技创新城核心区为例,详细介绍了2种建模技术的具体步骤。关键词:地貌模型;三维建模;纹理;SketchUp 地貌模型一般有二维模型和三维模型2种表达形式,三维地貌建模是地貌可视化的一个重要方面,它通过三维模型直观、形象地描述地貌的空间分布、位置、形态和内部结构特征1-3。三维地貌建模技术是当前自然地理学与地理信息系统领域关注的热点。SketchUp 是一款功能强大而又简单易用的三维草图设计工具4,与其他专业而又复杂的三维建模软件(如3D Max、AutoCAD 等相比,在快速构建三维地貌模型方面

3、具有明显优势5。SketchUp 还提供了直接从Google Earth 获取数据资源并将制作好的三维地貌模型导入Google Earth 的功能,可以实现三维地貌模型在Google Earth 上的无缝运行6。1 三维地貌模型的逻辑结构三维地貌模型可以表现三维空间中的地表形态与地表要素,同时展示地貌剖面的岩性与地质构造(褶皱、断层等。三维地貌模型主要由地貌骨架模型和地貌纹理构成。三维骨架模型可以利用SketchUp 等三维建模工具建立,建模数据使用ArcGIS、AutoCAD 等工具从地形图、数字高程模型(DEM或高程数据中提取;地貌纹理包括表征地表形态与地表要素的地表纹理和示意表达地形纵横

4、剖面的岩性与构造等地质特征的剖面纹理,纹理数据来源于遥感影像图、DEM 渲染图、地形图以及各种地质地貌专题图等,采用Photoshop 等图像处理软件按照三维骨架模型的地表二维大小和剖面尺寸处理为合适的地表纹理与剖面纹理。三维地貌模型的构成要素、数据来源以及基于SketchUp 的建模流程如图1所示。2 基于等高线的三维地貌建模技术基于等高线建立三维地貌模型是三维地貌建模的主要技术手段。等高线数据可以使用GIS 软件(如ArcGIS矢量化地形图等高线、基于DEM 的自动生成等高线或者对实测高程点进行插值计算生成等高线,这是等高线数据的主要来源;或者使用AutoCAD 软件对等高线或实测高程点7

5、进行处理,绘制生成多线段(PL的等高线数据。基于等高线的三维地貌建模技术关键是对等高线进行高程赋值,有2种赋值方法:一种是在SketchUp 软件中编辑等高线组的高程,另一种是先在AutoCAD 中设置等高线的标高(如图2 b 所示,然后再将带有标高的等高线数据导入SketchUp 中。为等高线设置高程值后,在SketchUp 中选中全部等高线,使用“绘图-沙盒-从等高线生成”工具,自动创建三维地貌曲面,对地貌曲面进行三维体构建及处理,删除冗余的线和面,即制作成三维地貌骨架模型(见图2 c。然后,根据骨架模型的剖面及平面尺寸,在Photoshop 中处理好合适的地表纹理和剖面纹理(剖图1 三维

6、地貌模型的构成要素及建模流程65第11卷第1期面与地表平面形状可以是规则的,也可以是不规则的,图2示例中为不规则的。最后,使用SketchUp 提供的纹理编辑工具为骨架模型添加地貌纹理,三维地貌模型即建模完成(如图2 d 所示,图中地表纹理为遥感影像图,剖面纹理为岩性图。图2 基于等高线的三维地貌建模3 基于高程点的三维地貌建模技术基于高程点建立三维地貌模型,是在AutoCAD 环境下,直接利用离散的高程点数据CAD 辅助工具(如湘源控规软件生成格网状三维地貌骨架模型(见图3 b,然后再将格网模型导入SketchUp 并建模为面状结构的三维地貌骨架模型,建立的模型剖面及水平面形状通常只能为规则

7、的(见图3 c。由离散高程点创建骨架模型的一个重要步骤是“字转高程”,可以使用湘源控规软件中“地形-字转高程”工具将高程标记点的标高数字转化为湘源控规软件自定义的高程格式,然后使用其“地形-三维模型”工具建立三维地貌的格网模型。可以通过“轴侧观察”命令,改变视点来观察格网模型的三维起伏变化。将格网模型导入SketchUp 中,创建面状的三维地貌曲面并创建三维体,即可建立地貌骨架模型。最后,使用SketchUp 提供的纹理编辑工具为骨架模型添加规则的地表纹理(图3 d 中为遥感影像图并叠加了蓝色的水系与红色的山脊线等地表要素和剖面纹理(图3 d 中为岩性图。由于该建模技术需要CAD 辅助工具,对

8、离散点的数量和分布有一定要求,并且建立的地貌模型是规则的,所以在三维地貌建模中不常使用。4 应用实例大连生态科技创新城核心区位于大连市甘井子区,地处北纬38°57235935,东经121°23402545,面积为15.26 km 2。首先,采用基于等高线的三维地貌建模技术建立了该区的三维地貌模型(见图4 a,然后,对该区内大东沟村附近3.5 km 2的一个规则的重点关注区块,采用基于高程点的三维地貌建模技术建立了一个局部的三维地貌模型(见图4 b,建模数据来源于12 000的纸质地形图。基于等高线的具体建模步骤为:扫描地形图并在ArcGIS 中采用12 000的大连行政区划

9、矢量数据配准,然后矢量化1 m 等高距的等高线,对等高线进行冗余删除和断线连接等处理后,生成1 m 等高距的数字等高线(存储为shp 文件,WGS84坐标系,并使用ArcGIS 三维工具生成了DEM 渲染图;使用SketchUp 的ArcGIS 插件SketchUp6ESRI 将等高线数据(1 m 等高距导入SketchUp 中建立三维地貌曲面,创建地貌三维体,建立三维地貌骨架模型;根据三维骨架模型的不规则的地表及剖面尺寸,使用Photoshop 软件处理好匹配的地表纹理与剖面纹理(如调色、渐变、裁剪等,地表纹理采用ArcGIS 生成的DEM 晕渲图,剖面纹理则是根据该地区基础地质资料制作的地

10、层岩性图;在SketchUp 中用纹理编辑工具为三维骨架模型添加地表纹理与剖面纹理,从而完成三维地貌模型;可以使用SketchUp 的Google Earth 放置模型工具,将三维地貌模型导入Google Earth 中,实现三维地貌模型的三维可视化浏览与网络发布,在Google Earth 中的浏览展示效果如图4 a 所示。基于高程点的具体建模步骤为:扫描地形图并在AutoCAD 中采集了重点关注区内的260个有代表性的离散高程点,矢量化了1条山脊线、1个湖泊及2条小溪流,存储为CAD 数据(dwg 格式;使用CAD 插件湘源控规软件中“地形-字转高程”工具将高程标记点的标高数字转化为湘源控

11、规软件的自定义高程格式,然后使用其“地形-三维模型”工具建立三维地貌的格网模型;将格网模型导入SketchUp 中,创建面状的三维地貌曲面并创建三维体,即可建立地貌图3 基于高程点的三维地貌建模杜 研等:基于SketchUp 的三维地貌建模技术a 初始等高线b 设置标高c 地貌骨架模型d 三维地貌模型a 离散高程点b CAD 中三维视图c 地貌骨架模型d 三维地貌模型地理空间信息66第11卷第1期骨架模型;根据三维骨架模型的地表及剖面尺寸(规则的,使用Photoshop 软件处理好匹配的地貌纹理(如调色、渐变、裁剪等,地表纹理采用已处理好的航拍影像图(2011年,0.5 m 分辨率,剖面纹理为

12、地层岩性图;将dwg 格式的地表要素数据导入SketchUp,在SketchUp 中编辑好地表要素(如颜色、线条样式等,使用纹理编辑工具为三维骨架模型添加剖面纹理、地表纹理及地表要素,从而完成三维地貌模型的构建(见图4 b,并进一步将其导入Google Earth 中。 图4 大连生态科技创新城核心区的三维地貌模型5 结 语三维地貌建模是根据各种原始资料建立地貌可视化模型的过程,旨在揭示地貌的构造形态、构造关系及动态演变,反映地球表面起伏状态及其发生、发展、分布规律。三维地貌建模的结果以三维数字模型的形式展示虚拟地貌环境。本文提出了三维地貌模型的逻辑结构,阐述了基于三维建模工具SketchUp

13、 的建模流程,介绍基于等高线和基于高程点的2种三维地貌建模技术,并以大连生态科技创新城核心区的地貌建模为例,详细介绍了2种三维地貌建模技术的具体步骤。基于SketchUp 的三维地貌建模技术,在创建三维地貌模型的同时,也实现了地表要素(山脊线、河流、湖泊等、地质构造(断层、褶皱等、地层岩性等地貌信息的三维可视化浏览,并可以充分利用Google Earth 及其提供的免费影像与地形数据,实现三维地貌模型的网络发布与三维可视化浏览。基于SketchUp 的三维地貌建模技术无疑是三维地貌快速建模的一种理想方法。参考文献1 杨景春, 李有利. 地貌学原理M. 北京: 北京大学出版社,20062 杜景龙

14、, 杨世伦, 张文祥,等.海岸地貌建模方法研究J.海洋通报, 2004, 23(6: 61-653 申健, 徐大伟, 蔡雄翔. 基于钻孔数据的滑坡三维地质建模研究J.东华理工大学学报:自然科学版, 2008, 31(2: 127-1374 Google 公司. SketchUp 用户手册EB/OL.http:/zh-cn.5 黄海峰, 易武. 利用Google SketchUp 快速构建滑坡三维模型J. 地球与环境, 2010, 38(3: 333-3386 马素颜, 吴健平, 周美娟,等. SketchUp 构建GIS 三维模型方法研究J. 计算机与信息技术, 2009 (Z1: 38-40

15、7 代莉, 陈春华, 聂焱. 在AutoCAD 环境下不规则三角网构建及等高线生成J.地理空间信息, 2011, 9(2: 40-42第一作者简介:杜研,硕士,主要研究方向为三维地貌建模与GIS应用。a Google Earth 环境下的三维地貌模型b SketchUp 环境下的三维地貌模型本刊声明为适应我国信息化建设,扩大本刊及作者知识信息交流渠道,本刊已加入中国核心期刊(遴选数据库、CNKI 中国期刊全文数据库、中文科技期刊数据库(全文版、CEPS 中文电子期刊服务收录期刊等数据库,所来稿件均认同加入以上数据库,如不同意,请事先声明,本刊另作处理。(本刊编辑部Index(V ol.11,N

16、o.1GEOSPATIAL INFORMATIONIIIunbiased and stabilized result. The second one is that model error makes it difficult to identify and position the gross error, which is introduced during the process of conversion from nonlinear function to a linear one. This article put forward a robust estimation metho

17、d which based on the fuzzy membership function to eliminate the influence of gross error. The fuzzy membership of the residuals were used to construct the weight matrix to assess the contribution of each observation quantity, and then the one contaminated by gross error would be given very little we

18、ight to increase the accuracy of parameter estimation. This algorithm was assessed by estimating the parameters in linear regression model and nonlinear regression model contaminated by gross error. It is found that this algorithm is robust to the influence of gross error, and outperforms the common

19、 least-square algorithm to give more accurate result.Key words fuzzy membership functions,nonlinear model, parameter estimation,the least square algorithm,robust estimation (Page:55Monitoring of the Coal Resource Exploitation Order in Shenfu Area Based on Remote Sensing and GIS by ZHOU Xuezhen Abstr

20、act This thesis chose monitor of coal mining to be a research topic, used of RS and GIS for technical support, combined with Remote Sensing data and the collected mineral rights information, basic topographic maps and other information, used interactive and visual interpretation method, dynamic moni

21、tored Shenfu coal mining areas in Shaanxi coal mining. It will achieve fast and efficient low-cost for law enforcement agencies to combat illegal mining activities to provide the scientific basis of law enforcement purposes.Key words coal, exploitation order, monitoring, Remote Sensing, GIS, explana

22、tion (Page:58Temporal and Spatial Variance of Land Use and Urban Heat Island in Suzhou City by MOU Xinyu Abstract By selecting Suzhou city as an experimental area, the paper classified underlying land surface types and retrieved land surface temperature from Landsat 5 TM images in 1986 and 2004 sepa

23、rately. Then the spatial and temporal variation of underlying surfaces and urban heat island effect were discussed, furthermore the effect of land use change to urban heat island was lastly studied. Research results show that the significant expansion of city area and dramatic changes of land use ty

24、pes have been taken place in the past 20 years, characterized by high-intensity conversion from water and vegetation area to impervious surface. Besides, the urban heat island distribution has expanded from old city area to the surroundings with the intensity rising from 3.12° to 4.76°, wh

25、ich exists a clear corresponding relationship with the urban expansion and land use change.Key words Remote Sensing,urban heat island,underlying land surface,land use,Suzhou (Page:613D Landform Modeling Technologies Based on SketchUp by DU Yan Abstract The 3D landform model is a hotspot of Physical

26、Geography and Geographical Information System fields currently, which directly and vividly describe the characteristics of geospatial distribution, position, shape and internal structure of the landform. The paper forwarded the logical structure of the 3D landform model, and introduced themodeling p

27、rocess of the 3D landform which used Google SketchUp as the 3D modeling tool, and introduced two kinds of modeling technologyrespectively based on the contours and the elevation points. Furthermore,the study took Dalian BEST City as example, elaborated the concretesteps of the modeling technologies.

28、 The results revealed that themodeling technology of the 3D landform based on SketchUp is an ideal method of rapid modeling.Key words landform model,3D modeling,texture, SketchUp (Page:64Object-oriented Information Extraction Method of Residential Buildings from High Resolution Image in Taian by DON

29、G Xiaojiao Abstract Traditional pixel-based classification method only uses the spectra feature of images. However, object-oriented method uses multi-scale segmentation based on a region combination algorithm and integrates spectral and spatial features in the segmentation based on image objects. It

30、 uses image object as the smallest classification unit and it is more suitable for high-resolution image analysis and processing. WitheCognition developer platform and QuickBird image of Taian city, this paper used multi-scale segmentation, nearest neighbor and membership functions classification an

31、d took full advantage of the spectrum, shape, texture, structure features and other spectra feature of QuickBird image to extract residential building features in experimental zone. The results show that object-oriented classification method effectively avoid the fracture of segmented regions and is

32、 more integrated, more accurate and more efficient in the extraction of images comparing with the traditional pixel-based classification method.Key words object-oriented, multi-scale segmentation, high resolution,residential building (Page:67Design and Realization of Land Intensive Use Evaluation Sy

33、stem of Development Zone Based on GIS by DING Yiting Abstract The system built a graphic-attribute integration spatial database, in the context of intensive utilization of land resources in development zones, using the GIS technology to obtain the basic data involved in the evaluation process of int

34、ensive utilization evaluation from the development zone outcome data. Furthermore this system implemented the functions such as database, automatic evaluation, results-based management and query analysis which were based on the intensive utilization of land resources evaluation in development zones

35、database-building system designed on the ArcGIS platform. The system achieved the goals of the improving the efficiency of the evaluation and maintain the accurate specification of achievement, by means of establishing intensive utilization of land resources evaluation system in development zone.Key

36、 words development zone,land intensive use evaluation,GIS(Page:70Porphyry Copper Deposits of Zhunuo Peripheral Remote Sensing Prospecting Forecast by CHEN Ming Abstract Based on the data source of ETM+, we masked the cloud, snow, quaternary, water and shadow by ENVI remote sensing image processing s

37、oftware. Using the characteristics of principal component analysis method, we carried out remote sensing hydroxyl and iron staining mineralized alteration information extraction on the porphyry copper deposits in Tibet Autonomous Region, Zhunuo and its outlying areas. We had made geological interpre

38、tations. And according to it we delineated the ore-finding prospect area. It provides prerequisites for the work of looking for ore in the outlying areas of the copper deposits.Key words characteristics of principal component analysis,minerali z ed alteration information,ore-finding prospect area (Page:73Application of MapGIS Map Correction and GPS Location in Geological Investigation by CHEN QingAbstract According to filed geological survey, we summed up a set of method using MapGIS correction geological maps and sett