3D noise mapping in urban areas

Noise mapping is the process of determining and visualizing noise impact on the environment in order to support environmental policies. Currently most noise impact studies are based on a 2D approach. The 3D output of noise simulation software is processed and visualized in 2D and combined with 2D topographical and other data, such as population distribution, to quantify the effects. The research described in this paper aims at improving visualization and assessment of noise impact on the environment by generating a 3D noise map in cases where 3D effects are relevant. Based on the specific demand, an approach is presented to generate a 3D noise map as a basis for noise impact studies. The proposed concept is proofed by applying it to a sample noise impact study. From experiences with the sample, it can be concluded that the 3D noise map offers significant insight in situations where 3D noise effects are relevant, i.e. in urban areas. Here, current 2D noise maps have limitations. In addition, more accurate assessment of noise impact is possible in particular when different floors of a building close to the noise source and/or behind noise barriers are considered. This paper also elaborates on accuracy aspects in all phases of noise modelling, including a presentation of initial experiments of 3D noise interpolation.     

基于紧密型二三维结合的GIS构架与系统实现

在三维系统中实时渲染二维图层是实现紧密型二三维结合GIS的关键.该文在二三维结合实现三维GIS的基础上,提出了基于LOD(Level of Detail)的二维图层与三维地形叠加的渲染构架和紧密型二三维结合GIS的初步系统构架,并利用ArcGIS Engine 开发包与World Wind开源软件实现了该原型系统.系统运行结果表明,该构架完全能够满足紧密型二三维结合GIS对渲染效果和效率的要求,成功解决了紧密型二三维结合系统的关键问题.     

Identification of Quaternary subsurface glacial deposits using 3D databases and GIS

To solve the problem of handling numerous data from drillings and geophysical surveys for specific information of subsurface geological formations, the use of databases and geographic information systems (GIS) is demonstrated. Geological formations are in 3D and commercial GIS packages are normally in 2D. This problem is solved here by a 1D database of the layering of the drillings and export of query results from the database to a 2D GIS. The queries will ask for grain size and altitude for the actual sedimentary layers. To include point data from ground penetrating radar (GPR) data survey profiles in a 2D GIS, a stepwise technique of dynamic segmentation has been developed. The points are digitized along sedimentary boundaries from 2D GPR profiles. The concept was applied on a small area of glacial sediments in Telemark, Norway. Results from the processes were clustering of points with properties connected to specific geological formations. The clustering subsurface geological formations were moraine ridges, a diamict layer, gravel and coarse sand above and below the diamict layer, till above bedrock, and glaciomarine deposits of gravel and sand. Information about extension of these geological formations is useful and essential for modelling of sedimentary environments and for aquifer modelling.     

A visualization-oriented 3D method for efficient computation of urban solar radiation based on 3D–2D surface mapping

The temporal and spatial distribution of solar energy in urban areas is highly variable because of the complex building structures present. Traditional GIS-based solar radiation models rely on two-dimensional (2D) digital elevation models to calculate insolation, without considering building facades and complicated three-dimensional (3D) shading effects. Inspired by the ‘texture baking’ technique used in computer graphics, we propose a full 3D method for computing and visualizing urban solar radiation based on image-space data representation. First, a surface mapping approach is employed to project each 3D triangular mesh onto a 2D raster surface whose cell size determines the calculation accuracy. Second, the positions and surface normal vectors of each 3D triangular mesh are rasterized onto the associated 2D raster using barycentric interpolation techniques. An efficient compute unified device architecture -accelerated shadow-casting algorithm is presented to accurately capture shading effects for large-scale 3D urban models. Solar radiation is calculated for each raster cell based on the input raster layers containing such information as slope, aspect, and shadow masks. Finally, a resulting insolation raster layer is produced for each triangular mesh and is represented as an RGB texture map using a color ramp. Because a virtual city can be composed of tens of thousands of triangular meshes and texture maps, a texture atlas technique is presented to merge thousands of small images into a single large image to batch draw calls and thereby efficiently render a large number of textured meshes on the graphics processing unit.     

温度升高和CO2浓度增加对冬小麦生物量的影响和不确定性分析（英文）

Impacts of climatic change on agriculture and adaptation are of key concern of scientific research. However, vast uncertainties exist among global climates model output, emission scenarios, scale transformation and crop model parameterization. In order to reduce these uncertainties, we integrate output results of four IPCC emission scenarios of A1FI, A2, B1 and B2, and five global climatic patterns of HadCM3, PCM, CGCM2, CSIRO2 and ECHAM4 in this study. Based on 20 databases of future climatic change scenarios from the Climatic Research Unit (CRU) , the scenario data of the climatic daily median values are generated on research sites with the global mean temperature increase of 1 ℃(GMT+1D), 2 ℃ (GMT+2D) and 3 ℃(GMT+3D). The impact of CO2 fertilization effect on wheat biomass for GMT+1D, GMT+2D and GMT+3D in China’s wheat-producing areas is studied in the process model, CERES-Wheat and probabilistic forecasting method. The research results show the CO2 fertilization effect can compensate reduction of wheat biomass with warming temperature in a strong compensating effect. Under the CO2 fertilization effect, the rain-fed and irrigated wheat biomasses increase respectively, and the increment of biomass goes up with temperature rising. The rain-fed wheat biomass increase is greater than the irrigated wheat biomass. Without consideration of CO2 fertilization effect, both irrigated and rain-fed wheat biomasses reduce, and there is a higher probability for the irrigated wheat biomass than that of the rain-fed wheat biomass.     

Embedding user-generated content into oblique airborne photogrammetry-based 3D city model

Oblique airborne photogrammetry-based three-dimensional (3D) city model (OAP3D) provides a spatially continuous representation of urban landscapes that encompasses buildings, road networks, trees, bushes, water bodies, and topographic features. OAP3D is usually present in the form of a group of unclassified triangular meshes under a multi-resolution data structure. Modifying such a non-separable landscape constitutes a daunting task because manual mesh editing is normally required. In this paper, we present a systematic approach for easily embedding user-generated content into OAP3D. We reduce the complexity of OAP3D modification from a 3D mesh operation to a two-dimensional (2D) raster operation through the following workflow: (1) A region of interest (ROI) is selected to cover the area that is intended to be modified for accommodating user-defined content. (2) Spatial interpolation using a set of manually controlled elevation samples is employed to generate a user-defined digital surface model (DSM), which is used to reform the ROI surface. (3) User-generated objects, for example, artistically painted road textures, procedurally generated water effects, and manually created 3D building models, are overlaid onto the reformed ROI.     

气候变化对小麦生物量影响的概率预测和不确定性分析

气候变化对农业生产的影响和适应一直是学界关注的重点。但是,由于气候模式输出、排放情景、尺度转换、模型参数化等研究过程中存在的不确定性,往往导致研究结果也存在较大的不确定性。为减少研究结果的不确定性,本研究综合了IPCC 四个排放情景(A1FI、A2、B1、B2) 以及5 个全球气候模式(HadCM3, PCM, CGCM2, CSIRO2, ECHAM4) 的输出结果,基于英国CRU 气候中心的20 个未来情景数据库,生成全球平均温度升高1℃(GMT+1D)、2℃ (GMT+2D)、3℃ (GMT+3D) 下研究站点的气候日值中值情景数据,利用过程模型CERES-Wheat 和概率预测方法研究CO₂肥效作用和GMT+1D、GMT+2D、GMT+3D对我国小麦主产区小麦生物量的影响。研究结果表明:CO₂肥效作用可以补偿由于温度升高而造成的小麦生物量减产且补偿作用随着温度的升高而增加。当有CO₂肥效作用时,灌溉小麦和雨养小麦生物量均增加,且随着温度的升高生物量的增长程度增大,相同情景下,雨养小麦生物量的增高概率大于灌溉小麦。当不考虑CO₂肥效作用时,灌溉小麦和雨养小麦生物量均降低,且灌溉小麦生物量减产的概率大于雨养小麦减产概率。     

基于面板数据的中国R&D投入对城镇化影响分析

利用中国30个省区2002-2012年R&D投入和城镇化水平的面板数据,通过单位根检验、协整性检验和面板数据模型,探讨中国R&D投入对地区城镇化发展水平的影响。结果表明：①中国各省区城镇化水平与R&D投入存在长期稳定关系,但城镇化水平的科技支撑基础仍处于较低水平,并且不同省区的R&D投入产出存在较大差异。②总体上看来,R&D人员投入产出弹性高于R&D经费投入,说明城镇化对R&D人员投入的依赖性更大。③R&D投入对城镇化的作用与其所处的城镇化阶段有关,同时,R&D投入与城镇化的协调度也是影响R&D投入产出的关键因素。④误差修正模型结果表明,R&D短期投入对城镇化的影响存在一定的滞后效应。     

基于多旋翼无人机倾斜摄影测量的沙丘三维形态研究

无人机倾斜摄影技术是近年来发展起来的新型测量方法,具有高效率、高精度、非接触、大范围等优点。本研究采用多旋翼无人机,结合精确测定的地面控制点,实现了对新月形沙丘群三维形态的精确测量。结果表明：无人机倾斜摄影测量的均方根误差小于18 mm,可以满足大比例尺地形测量的要求。利用该技术获取的多种测量参数表明,新月形沙丘二维与三维形态之间存在良好的相关性,基于这些关系,可以实现二维遥感影像量测结果向沙丘高度、沙丘体积等三维参数的转换。沙丘剖面形态可以采用非线性函数精确描述,为沙丘形态精确建模提供了参考。无人机倾斜摄影技术获取的沙丘三维形态参数,对于深入认识沙丘形态动力过程具有重要参考价值。     

Map-Reading Skill Development with 3D Technologies

Landforms often are represented on maps using abstract cartographic techniques that the reader must interpret for successful three-dimensional terrain visualization. New technologies in 3D landscape representation, both digital and tangible, offer the opportunity to visualize terrain in new ways. The results of a university student workshop, in which traditional 2D versus 3D digital and tangible models were tested, suggest that map-reading skill development is greater when using the 3D technologies.     

Vario-scale data structures supporting smooth zoom and progressive transfer of 2D and 3D data

This paper introduces the concept of the smooth topological Generalized Area Partitioning (tGAP) structure represented by a space-scale partition, which we term the space-scale cube. We take the view of ‘map generalization as extrusion of data into an additional dimension’. For 2D objects the resulting vario-scale representation is a 3D structure, while for 3D objects the result is a 4D structure.

This paper provides insights in: (1) creating valid data for the cube and proof that this is always possible for the implemented 2D tGAP generalization operators (line simplification, merge and split/collapse), (2) obtaining a valid 2D polygonal map representation at arbitrary scale from the cube, (3) using the vario-scale structure to provide smooth zoom and progressive transfer between server and client, (4) exploring which other possibilities the cube brings for obtaining maps having non-homogenous scales over their domain (which we term mixed-scale maps), and (5) using the same principles also for higher dimensional data; illustrated with 3D input data represented in a 4D hypercube.

The proposed new structure has very significant advantages over existing multi-scale/multi-representation solutions (in addition to being truly vario-scale): (1) due to tight integration of space and scale, there is guaranteed consistency between scales, (2) it is relatively easy to implement smooth zoom, and (3) compact, object-oriented encoding is provided for a complete scale range.     

城市三维地理信息系统中三维模型的快速构建方法

大规模三维模型的快速构建一直是影响城市三维地理信息系统(3DUGIS)发展的一个重要因素.基于3DUGIS中景观模型的表达原则与分类,分别针对抽象的点、线、面状对象提出符号匹配和三角剖分的批量三维模型构建方法.这种建模方法方便、快捷、自动化程度高,可广泛应用于城市景观中地面、河流、道路、绿地、规则建筑物、地下管线等地物的三维建模.通过对上述三维模型快速构建方法的实现,验证了三维模型生成的效果和效率.     

Recognition of Significant Surface Soil Geochemical Anomalies Via Weighted 3D Shortest-Distance Field of Subsurface Orebodies: A Case Study in the Hongtoushan Copper Mine,NE China

Natural Resources Research - Quantitative prediction of concealed mineralization is always confronted with difficulties in comprehensive analysis between 2D and 3D data and between qualitative and...     

三维含拓扑地质剖面三角剖分可视化研究

三维剖面是地质对象表达和地质问题分析中最基本和最常用的数据。该文分析三维复杂地质折剖面可视化存在的问题,并提出展开剖分算法。该方法保证了各点之间的水平距离与剖面拓扑关系不变,能够对由"多边形-弧段-结点"矢量结构构成的三维折剖面进行有效剖分。在此基础上实现了三维剖面的可视化,尤其合理解决了纹理映射中的纹理变形与重复接缝等问题。     

Davis二倍数规律与Zipf三参数模型的等价性证明——关于城市规模分布法则的一个理论探讨

本文从城市规模分布的Davis 二倍数规律（2n 规律：ai= ai+ n·2n,fi= fi+ n·2- n）中推导出具有一般意义的三参数Zipf模型：P（r）= C（r- α）- dz,揭示了2n 规律隐含的分形几何性质, 论证了2n 法则为Zipf维数dz= 1 时的特殊情形, 并将2n 规律推广到具有普遍意义的δn 规律, 给出了Zipf维数及分维与邻级倍数δ的数值关系：dz= 1/D= ln2/lnδ。最后从三个方面对文中的理论成果进行了实证分析。     

东南极埃默里冰架东缘赖茵博尔特丘陵构造变形过程及其构造意义

对赖茵博尔特丘陵地区的构造变形过程分析表明,该地区发育4期主要构造变形.D1期主要是区域性近EW向片麻理形成阶段,其变形时代为＞970 Ma;D2期是在正片麻岩形成了近EW向轴面陡立韧性剪切褶皱,以及剪切面理上发育的各种紧闭不对称褶皱和低角度拉伸线理,其变形时代为新元古代早期.D3期变形发生在寒武纪早期,以构造抬升至地...     

南极地区地磁扰日变化S_D场特征

利用南极地磁资料研究了地磁扰日变化ＳＤ场特征。１）ＳＤ场变化不如Ｓｑ场变化规则,无明显的昼夜差异;太阳活动高年（１９９１年）比下降年（１９９４年）ＳＤ场变化更强烈。２）极隙区中山站ＳＤ场变幅比亚极光区长城站和北半球低纬区北京台的ＳＤ场变幅大１０倍以上。３）中山站Ｓ０Ｄ（Ｈ）变化呈“正弦波”形态,与长城站和北京台Ｓ０Ｄ（Ｈ）变化形态相反。４）中山站Ｓ０Ｄ等效电流矢量在早晨－下午（０２～１５ｈ）矢量方向为反时针西向,下午－夜间（１５～０２ｈ）矢量方向为顺时针东向,这是由极区东向、西向电射流和极区电流涡旋所引起;长城站与北京台Ｓ０Ｄ等效电流矢量很小,这是由极区东向和西向电射流的影响所致。     

网络环境下数据简化与数据调度的若干关键技术

网络环境下进行二维电子地图与三维虚拟场景集成,关键问题之一是数据快速、有效地传输与表达。为了解决网络电子地图与三维虚拟场景集成过程中数据快速传输问题,该文讨论了空间数据多级存储、网络数据流压缩、矢栅数据有机结合、纹理模型及原型模型库等网络传输瓶颈解决方案和模型数据简化方法,为后续网络电子地图和三维虚拟场景集成系统的开发奠定基础。     

裂隙性粘土粒度成分的分形结构

根据分形理论,研究了我国普遍分布的裂隙性粘土粒度成分之分形结构特征,其分维值介于2.600～3.000之间,且灰白色隙壁粘土的分维值≥黄褐色母体土的分维值。在此基础上,讨了分维与土体物质成分、结构特征的关系,以及它所代表的工程地质意义。