絲綢之路文物古跡 - 甘肅鎖陽城 - 三維建模方法研究 - 蔡磊 - 圖文-

1、 收稿日期:2014-01-07。項(xiàng)目來源:國土資源部煤炭資源勘查與綜合利用重點(diǎn)實(shí)驗(yàn)室自主研究課題資助項(xiàng)目(ZZ2013-3。蔡磊1,2,康荔1,2,代巨鵬2,朱偉2(1.國土資源部 煤炭資源勘查與綜合利用重點(diǎn)實(shí)驗(yàn)室,陜西 西安 710001;2.陜西省煤田地質(zhì)局 物探測量隊(duì),陜西 西安 710001摘要:以航空攝影和全野外數(shù)字化測量等手段,獲取豐富的地形地貌數(shù)據(jù),再結(jié)合多種GIS 數(shù)據(jù)處理方法獲取鎖陽城建模數(shù)據(jù),通過精細(xì)建模和實(shí)景貼圖技術(shù)建立城墻模型,最終在SuperMap 平臺(tái)下建立三維場景。詳細(xì)介紹了模型數(shù)據(jù)獲取、模型數(shù)據(jù)處理和建模的具體方法。關(guān)鍵詞:古城墻;三維建模;場景中圖分類號(hào):P

2、208 文獻(xiàn)標(biāo)志碼:B 文章編號(hào):1672-4623(201404-0105-02鎖陽城原名苦峪城,在甘肅省安西縣城東南約70 km 的戈壁上,是我國目前保存最為完整的漢唐古城之一,也是古代沙漠化演進(jìn)過程滄桑變化的典型標(biāo)本 1。基于甘肅絲綢之路申報(bào)世界文化遺產(chǎn)的需要,鎖陽城三維建模是必要的。目前三維建模技術(shù)日趨成熟,并已經(jīng)應(yīng)用到很多方面,對(duì)于建模技術(shù)方法的研究則主要集中在城市建模和規(guī)則地物建模方面2,針對(duì)古城墻遺跡的三維建模的研究很少,還沒有形成統(tǒng)一且成熟的建模方法。本文針對(duì)古跡現(xiàn)狀,靈活運(yùn)用航測相關(guān)技術(shù),研究了從模型數(shù)據(jù)獲取到數(shù)據(jù)處理,再到數(shù)據(jù)建模的古城墻三維建模方法。1技術(shù)路線鎖陽城地形凹

3、凸起伏,城墻破損嚴(yán)重,采用常規(guī)方法建模實(shí)現(xiàn)難度較大。本文首先采用立體測圖技術(shù)采集地形高程點(diǎn)和城墻特征點(diǎn);然后在ArcGIS 中對(duì)數(shù)據(jù)進(jìn)行處理,在3Dmax 中進(jìn)行地形和城墻建模以及實(shí)景貼圖;最后將三維地形模型和城墻模型導(dǎo)入到SuperMap 中,建立三維場景。技術(shù)路線圖如圖1。2三維建模根據(jù)數(shù)據(jù)處理方式和建模方法的不同,鎖陽城三維建模分為地形建模、城墻建模和其他要素建模3個(gè)部分。模型的幾何數(shù)據(jù)綜合利用航空攝影測量、內(nèi)業(yè)航空攝影測量工作站通過立體數(shù)據(jù)采集、全野外數(shù)字化散點(diǎn)測量和GIS 數(shù)據(jù)處理等方法獲取。2.1地形建模為更準(zhǔn)確、更逼真地反映鎖陽城地形,地形建模采用地形模型疊加DOM 的方式。鎖陽

4、城影像數(shù)據(jù)采用無人機(jī)獲取的高清影像,經(jīng)正射糾正為DOM。在立體數(shù)據(jù)采集中,采用2 m×2 m 的采樣距離,提取地形高程點(diǎn)。在ArcMap 中展繪高程點(diǎn),采用克里金法插值出地形柵格,然后采用0.5 m 等高距從地形柵格上提取等值線。將等值線導(dǎo)入到3DMAX 9中,采用地形工具生成地形模型,再與處理好的正射影像DOM 疊加,形成三維地形模型3。2.2城墻建模鎖陽城歷史悠久,城墻破損嚴(yán)重,為更準(zhǔn)確地反映城墻現(xiàn)狀,本文利用高清航空攝影影像進(jìn)行航空攝影測量工作站立體數(shù)據(jù)采集。采用立體測圖方法,繪出城墻的頂?shù)走吘€,對(duì)城墻表面變化較大的地方對(duì)照立體影像采集特征線和特征點(diǎn)。為了使一些破壞的城墻區(qū)域數(shù)

5、據(jù)更為精確,又采用了全野外數(shù)字化散點(diǎn)測量獲取部分?jǐn)?shù)據(jù)。在ArcMap 中根據(jù)特征線和特征點(diǎn)創(chuàng)建TIN,然后 3D M A X 環(huán)境P h o t o s h o p 環(huán)境圖1鎖陽城三維建模技術(shù)路線地理空間信息·106·第12卷第4期采用0.2 m間距提取表面等值線,并對(duì)等值線作平滑處理。將城墻等值線導(dǎo)入到3DMAX 9中,采用地形工具生成城墻三維模型。為達(dá)到與真實(shí)城墻逼真的效果,模型建好后要進(jìn)行實(shí)景紋理貼圖,貼圖應(yīng)保證其在水平和垂直兩個(gè)方向上無傾斜,明暗及對(duì)比關(guān)系合適,顏色與模型周邊匹配合理,無樹木或其他障礙遮擋4。城墻三維模型如圖2所示。 圖2城墻三維模型2.3其他地物建

6、模鎖陽城中除城墻外,還有許多其他要素,如磚鋪路、樓梯、古跡碑等需要進(jìn)行建模。磚鋪路在建模時(shí)采用正射影像為底圖,矢量化出路的邊線,在3Dmax 9中將建好的地形模型調(diào)整到俯視狀態(tài),然后對(duì)矢量圖進(jìn)行映射,從三維地形上提取出磚鋪路,最后進(jìn)行貼圖處理。 由于樓梯很窄,在立體測圖系統(tǒng)中難以準(zhǔn)確采集數(shù)據(jù),因此,樓梯的建模數(shù)據(jù)主要由野外RTK 實(shí)測獲取。將RTK 測得的數(shù)據(jù)在Cass 中展點(diǎn),然后導(dǎo)入到3Dmax 9中進(jìn)行建模。樓梯模型如圖3所示。 圖3樓梯三維模型古跡碑建模首先野外量測尺寸,然后在3Dmax 9中進(jìn)行建模,最后將建立好的模型根據(jù)RTK 測得的位置數(shù)據(jù)放到具體點(diǎn)位。古跡碑模型如圖4所示。 圖

7、4古跡碑模型2.4模型優(yōu)化數(shù)據(jù)量大是三維建模經(jīng)常遇到的情況。本研究在建模前制定了嚴(yán)格的建模規(guī)范,來優(yōu)化模型結(jié)構(gòu),降低模型數(shù)據(jù)量。建模過程中盡量采用最少的面來達(dá)到模型表達(dá)的效果,能用貼圖表現(xiàn)的要避免建模5。建立完成的地物模型,采用3Dmax 中attach 命令將同一地物模型要素合為一個(gè)整體,并進(jìn)行相應(yīng)命名6。3三維場景建設(shè)在3Dmax 中建立的三維模型,通過SuperMap Max Plugin 6R 7插件導(dǎo)出超圖空間數(shù)據(jù)集。采用超圖的SCV(大容量模型緩存格式,能很好地解決大模型的顯示和運(yùn)行問題。采用超圖插件導(dǎo)出地物模型時(shí),設(shè)置模型地理坐標(biāo),將模型精確定位到三維場景中的具體位置。Super

8、Map Deskpro 6R 軟件具有方便的場景設(shè)置工具,能對(duì)相機(jī)模式、視圖模式、場景要素、太陽特效、模型陰影等進(jìn)行設(shè)置。導(dǎo)入到超圖三維場景中的模型數(shù)據(jù),系統(tǒng)建立默認(rèn)屬性表,可以建立新屬性字段,存儲(chǔ)模型其他相關(guān)信息,“型屬結(jié)合”,使模型的信息承載力更加強(qiáng)大。三維場景如圖5所示。圖5鎖陽城三維場景參考文獻(xiàn)1 李并成.鎖陽城遺址及其周圍古墾區(qū)沙漠化過程考J.絲綢之路,2011(18:27-302 張新利,趙力彬,閆會(huì)杰,等.西安世園會(huì)三維系統(tǒng)的設(shè)計(jì)與實(shí)現(xiàn)J.測繪通報(bào),2012(11:84-863 張明旺.基于ArcGIS 和3DS Max 的數(shù)字廠區(qū)三維可視化系統(tǒng)建設(shè)與應(yīng)用研究D.蘭州:蘭州交通大

9、學(xué),20124 吳延,王曉峰.基于實(shí)景圖像分色技術(shù)的三維全景展示系統(tǒng)研究J.測繪通報(bào),2012(2:71-735 孫悅,鮑泓,馬楠,等.中國古建筑虛擬現(xiàn)實(shí)系統(tǒng)的數(shù)據(jù)采集和處理J.北京聯(lián)合大學(xué)學(xué)報(bào):自然科學(xué)版,2008,22(3:40-446 劉虎,陳漢文.基于3DS MAX 的校園三維模型室內(nèi)外一體化制作J.地理空間信息,2013,11(2:53-557 北京超圖.SuperMap GIS 6R 桌面產(chǎn)品使用手冊Z.北京:北京超圖軟件股份有限公司,2012第一作者簡介:蔡磊,碩士,主要從事航空攝影測繪、遙感與地理信息系統(tǒng)應(yīng)用、數(shù)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