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1.
James D. Eynard Bernhard Jenny 《International journal of geographical information science》2016,30(10):1923-1943
Shadowed contour lines vary line width. Illuminated contour lines additionally vary color based on an angle of illumination. Illuminated and shadowed contour lines date back to the mid-nineteenth century, but their effectiveness compared to conventional contour lines has not been fully examined. Currently, illuminated and shadowed contour lines are not widely used in computer-based cartography because they are not included in most GIS apmaking software. This article introduces improvements to existing algorithms for creating illuminated and shadowed contour lines from digital elevation data. A software package is made available to allow mapmakers to more easily make customized illuminated and shadowed contour maps. A user study comparing illuminated and shadowed contour lines to conventional contour lines and shaded relief with approximately 400 participants was conducted. Results indicate that map-readers can interpret relative height differences between points better and quicker with illuminated contour lines than regular contour lines or shaded relief. Study participants were able to select absolute maxima on an unlabeled illuminated contour map and a labeled regular contour map with equal accuracy and speed. These findings suggest that illuminated contour lines could be used more frequently for improved visualization of terrain and other surface data on maps. 相似文献
2.
Terrain maps displaying hill-shading with curvature 总被引：2，自引：0，他引：2
Many types of maps can be created by neighborhood operations on a continuous surface such as provided by a digital elevation model. These most commonly include first derivatives slope or aspect, and second derivatives planimetric or profile curvature. Such variables are often used in geomorphic analyses of terrain. First derivatives also provide subtle enhancements to hill-shaded maps. For example, some maps combine oblique and vertical illumination, with the latter reflecting variations in slope.This study illustrates how second derivative maps, in conjunction with hill-shading, can cartographically enhance topographic detail. A simple conic model indicates that image-tone edges where slope or aspect varies by less than 0.5° are visible on curvature maps. Hill-shaded images combined with curvature enhance the continuity of naturally occurring tonal edges, especially in strongly illuminated areas. Variations in planimetric and profile curvature seem to be especially effective at highlighting convergent and divergent drainages and variations in erosion rate between or within sedimentary units, respectively. Shading curvature with consideration given to illumination models can add detail to hill-shaded terrain maps in a manner similar to cognitive models employed by map viewers. 相似文献
3.
Carlos Carbonell Carrera Bogdan Vlad Avarvarei Elena Liliana Chelariu Lucia Draghia Simona Catrinel Avarvarei 《The Journal of geography》2017,116(5):197-205
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. 相似文献
4.
D. C. MASON D. G. CORR A. CROSS D. C. HOGG D. H. LAWRENCE M. PETROU 《International journal of geographical information science》2013,27(3):195-215
Abstract Remotely-sensed data constitute a major potential source of input to geographical information systems (GIS)However, these data often have a relatively poor classification accuracy compared with that of the cartographic data from maps with which they may be combined in the course of GIS analysis. The possibility exists of using data sets (in the form of digital maps) resident within a GIS in order to improve this accuracy, before the classified image is incorporated into the GIS. Results are discussed from a British Alvey Information Technology project to develop a system for the knowledge-based segmentation and classification of remotely-sensed terrain images, in which the knowledge contained in digital map 相似文献
5.
Automatic extraction of lineament information from satellite images using digital elevation data 总被引：1，自引：0，他引：1
Using conventional visual interpretation in lineament analysis presents two main problems. The first is subjectivity, introduced because of the bias of various interpreters. The second problem is that lineaments detected from satellite images are constrained by the direction of the illumination source. Since lineament identification mainly involves recognition of diagnostic morphological features, the use of digital elevation can contribute significant information about these features. Further, in generating images using digital elevation data, the direction of illumination can easily be controlled. Thus, the use of digital elevation data offers the possibility of revealing features not apparent in regular satellite images.We discuss a sequential line detection method for extraction of linear features from digital elevation data. In this method, raw elevation data is used for generating shaded relief images using the Lambertian reflection model, wherein the illumination direction is controlled by the user. The Directional Segment Detection Algorithm (DSDA) is used for detecting linear topographic features in user-defined trends. Locational information about these linear features is stored in the computer as coordinate pairs amenable to editing and subsequent analysis. Finally, three-dimensional terrain models are generated by combining the digital elevation data and satellite images. The experiments were carried out using digital elevation data of southwest Japan and Landsat MSS data. 相似文献
6.
Lunar landforms are the results of geological and geomorphic processes on the lunar surface. It is very important to identify the types of lunar landforms. Geomorphology is the scientific study of the origin and evolution of morphological landforms on planetary surfaces. Elevation and relief amplitude are the most commonly used geomorphic indices in geomorphological classification studies. Previous studies have determined the elevation classification criteria of the lunar surface. In this paper, we focus on the classification criteria of the topographic relief amplitude of the lunar surface. To estimate the optimal window for calculating the relief amplitude of the lunar surface, we use the mean change-point method based on LOLA (Lunar Orbiter Laser Altimeter) Digital Elevation Model (DEM) data and SLDEM2015 DEM data combining observations from LOLA and SELenological and Engineering Explorer Terrain Camera (SELENE TC). The classification criterion of the lunar surface relief amplitude is then determined according to the statistical analysis of basic lunar landforms. Taking the topographic relief amplitudes of 100 m, 200 m, 300 m, 700 m, 1500 m and 2500 m as thresholds, the lunar surface is divided into seven geomorphic types, including minor microrelief plains (< 100 m), minor microrelief platforms [100 m, 200 m), microrelief landforms [200 m, 300 m), small relief landforms [300 m, 700 m), medium relief landforms [700 m, 1500 m), large relief landforms [1500 m, 2500 m) and extremely large relief landforms (≥ 2500 m). The minor microrelief plains are mainly distributed in the maria and the basalt filled floors of craters and basins, while the minor microrelief platforms are mainly in the transition regions between the maria and highlands. The microrelief landforms are mainly located in regions with relatively high topography, such as wrinkle ridges and sinuous rilles in the mare. The small relief landforms are mainly scattered in the central peak and floor fractures of craters. The medium relief landforms are mainly distributed in the transition regions between crater floors and crater walls, between crater walls and crater rims, between basin floors and basin walls, and between basin walls and basin rims. Large and extremely large relief landforms are mainly found along crater walls and basin walls. The classification criteria determination for assessing lunar surface relief amplitude described in this paper can provide important references for the construction of digital lunar surface geomorphology classification schemes. 相似文献
7.
月球地貌是月球表面发生的地质和地貌过程的结果,月球地貌单元的划分和等级分类体系的构建是月球地貌学研究的基础,也是月球地貌图制图的基础和关键科学问题。地貌学是研究形态和成因的科学,高程和起伏度是最基本的地貌指标。本文基于LOLA（Lunar Orbiter Laser Altimeter） DEM数据以及LOLA和SELENE TC（Terrain Camera）融合的DEM数据（SLDEM2015,文中简称SLDEM）,利用均值变点法确定月表起伏度计算的最佳窗口,并以起伏度100 m、200 m、300 m、700 m、1500 m及2500 m为阈值将月球表面分为微起伏平原（< 100 m）、微起伏台地[100 m, 200 m）、微小起伏丘陵[200 m, 300 m）、小起伏山地[300 m, 700 m）、中起伏山地[700 m, 1500 m）、大起伏山地[1500 m, 2500 m）及极大起伏山地（≥ 2500 m）地貌7个类型。划分结果显示：微起伏平原主要分布在月海平原区域、部分有玄武岩充填的撞击盆地的盆底区域以及撞击坑坑底区域;微起伏台地主要分布在月海和月陆区域的交界区域;微小起伏丘陵主要分布在月溪和皱脊等构造单元区域;小起伏山地主要分布在撞击坑中央峰及坑底断裂区域;中起伏山地主要分布在撞击坑坑底和坑壁过渡区域、撞击坑坑壁和坑缘过渡区域、撞击盆地盆底与盆壁过渡区域以及盆壁与盆缘过渡区域;大起伏和极大起伏山地主要分布在撞击坑坑壁区域及撞击盆地盆壁区域。本文确定的月表起伏度分级标准可以对月表数字地貌分类体系的构建和月球地貌图集的编研提供定量标准和重要参考。 相似文献
8.
Timofey Samsonov Sergey Koshel Dmitry Walther Bernhard Jenny 《International journal of geographical information science》2019,33(10):2072-2093
Supplementary contour lines are placed between regular contour lines to visualize small but important forms that regular contour lines are unable to show. On topographic maps, typical forms are hillcrests, depressions, saddles, terraces, banks, and levees. No automated method for the selection of supplementary contour lines has been described so far. We document cartographic design principles for the selection of supplementary contour lines for topographic maps, and present an automated method for their placement. Results of the automated method are similar to manually placed supplementary contour lines. Our method helps map authors to create contour line maps that more effectively illustrate relevant small details in maps showing terrain elevation or other scalar fields. 相似文献
9.
Magnus Johansson 《Geomorphology》1999,26(4):339
A 3873-km2 large rectangular area of the Precambrian basement in south-western Sweden has been investigated regarding gross morphology of palaeosurfaces. GIS and digital elevation data were used to construct maps of relative and absolute relief and E–W trending height profiles. Three different palaeosurfaces were recognised and delimited; the very even sub-Cambrian peneplain in the east at an intermediate altitudinal position, an uplifted and broken part of the sub-Cambrian peneplain in the centre at the highest present elevation, and in the western coastal areas a joint-aligned valley landscape with high relative relief, probably an exhumed Mesozoic etch-surface. Phanerozoic faulting has dissected the different palaeosurfaces into tectonic blocks, which are shown from trend surface analysis to be tilted in different directions and to different degrees, characteristic and decisive for the morphological development. 相似文献
10.
基于DEM的地貌实体单元自动提取方法 总被引：17，自引：4，他引：13
我国传统地貌基本形态类型分类强调地貌单元的完整性,界线划分沿地貌实体边界而非规则统计单元,目前尚缺乏地貌实体单元的有效自动提取方法。针对这一难点,本文提出一种基于DEM的地貌实体单元数字提取方法。利用坡度分级,并搜索相邻栅格单元、计算坡度级别内相互连通栅格的面积,建立坡度、面积阈值综合判别规则进行山地平原的自动划分;利用地形倒置、水文淹没分析,将山体划分的二维判别规则扩展到实际三维地形中,并结合地形结构线提取算法进行山体界线自动提取、确定山地地貌实体单元。结果表明,该方法符合我国传统地貌分类体系,能够较好实现山地/平原的自动划分和山体界线的数字提取。 相似文献
11.
Richard J. Pike 《The Professional geographer》2013,65(2):263-274
Digital terrain modeling has a micro- and nanoscale counterpart in surface metrology, the numerical characterization of industrial surfaces. Instrumentation in semiconductor manufacturing and other high-technology fields can now contour surface irregularities down to the atomic scale. Surface metrology has been revolutionized by its ability to manipulate square-grid height matrices that are analogous to the digital elevation models (DEMs) used in physical geography. Because the shaping of industrial surfaces is a spatial process, the same concepts of analytical cartography that represent ground-surface form in geography evolved independently in metrology. The surface topography of manufactured components, exemplified here by automobile-engine cylinders, is routinely modeled by variogram analysis, relief shading, and most other techniques of parameterization and visualization familiar to geography. This article introduces industrial surface-metrology, examines the field in the context of terrain modeling and geomorphology and notes their similarities and differences, and raises theoretical issues to be addressed in progressing toward a unified practice of surface morphometry. 相似文献
12.
Richard J. Pike 《The Professional geographer》2001,53(2):263-274
Digital terrain modeling has a micro‐ and nanoscale counterpart in surface metrology, the numerical characterization of industrial surfaces. Instrumentation in semiconductor manufacturing and other high‐technology fields can now contour surface irregularities down to the atomic scale. Surface metrology has been revolutionized by its ability to manipulate square‐grid height matrices that are analogous to the digital elevation models (DEMs) used in physical geography. Because the shaping of industrial surfaces is a spatial process, the same concepts of analytical cartography that represent ground‐surface form in geography evolved independently in metrology. The surface topography of manufactured components, exemplified here by automobile‐engine cylinders, is routinely modeled by variogram analysis, relief shading, and most other techniques of parameterization and visualization familiar to geography. This article introduces industrial surface‐metrology, examines the field in the context of terrain modeling and geomorphology and notes their similarities and differences, and raises theoretical issues to be addressed in progressing toward a unified practice of surface morphometry. 相似文献
13.
三维地形模型光照和动态显示的新方法 总被引：5，自引：0，他引：5
介绍了一种具有真实感的三维地形模型光照显示的新方法,给出了相应的构建多精度数字高程模型ＤＥＭ的步骤,并讨论了适应三维地形模型光照显示的消隐,可见性测试,光照模型,浓淡处理等处理算法的方法,此外还讨论了适合身机动态显示三维地形模型的方法。 相似文献
14.
The improvement of geospatial thinking is essential for success in science, technology, engineering, and mathematics disciplines. Training based on the geovisualization and interpretation of landforms can develop the relief interpretation skill. The research reported here focuses on the study of relief visualization and interpretation, using results from a workshop performed with forty-six university students using different displays of geovisualization in a Spatial Data Infrastructure (SDI) geoportal: LiDAR digital surface model, HillShade digital terrain model, digital elevation model, slope model, high-resolution orthophoto, and topographic map. The results are compared with those of another workshop on the same topic carried out with augmented reality (AR) technology. The relief interpretation skill improvement was measured before and after each of the workshops using the Topographic Map Assessment test. The results with the SDI geoportal showed a significant gain in relief interpretation skill between pretest and posttest scores but less than the gain obtained with AR. No differences were found due to the gender of the participants in either case. Key Words: augmented reality, geospatial thinking, landform interpretation, relief interpretation skill, Spatial Data Infrastructure. 相似文献
15.
1:25万《毛乌素风沙地貌图》的编制 总被引：2，自引：1，他引：1
风沙地貌图是认识和研究沙漠（沙地）最基本的图件。毛乌素沙漠沙丘类型复杂多样,对毛乌素沙漠风沙地貌进行详细划分,编制《毛乌素风沙地貌图》对深入研究毛乌素沙漠风沙地貌成因、分布和演化规律具有重要意义。根据编图范围和印刷纸张的要求,将《毛乌素风沙地貌图》的比例尺确定为1∶25万。选用1∶10万地形图作为基础资料,并以1∶5万地形图和1∶20万地质图作为补充资料;专题内容资料以landset-8卫星影像为主,结合Google Earth影像对部分细节内容进行补充。在形态成因相关分析的基础上建立地貌分类体系,将毛乌素沙漠地貌划分为风成地貌、湖成地貌、流水地貌、干燥地貌、黄土地貌和其他等6类,其中风成地貌是本图重点展示的内容。根据毛乌素沙漠的地貌特征,采用图例系统和地貌晕渲相结合的方法表示毛乌素沙漠的具体地貌类型,其中图例系统包括底色、符号、代码和注记等多种表示方法,地貌晕渲的使用增强了地貌的立体感,使地图看起来更加美观。 相似文献
16.
This article describes a methodology to localise areas with high potential towards natural snowpack instability under particular meteorological conditions, at the scale of an Alpine valley. Localisation is based on statistically relating known release areas of past avalanche events to maps of: (1) slope inclination, (2) slope orientation (aspect), (3) elevation, (4) distance from crest lines, (5) terrain roughness and (6) concavities/convexities. The maps have been built using two different GIS softwares while the statistical analyses have been performed with a specific software handling also Fuzzy Set theory algorithms. The results of the statistical analyses have been verified on test release—areas which have not been used as input data for the statistical analyses. Verification allowed to quantify how reliably the susceptibility values were calculated, to compare the values obtained using different combinations of terrain features and to finally decide on the most efficient combination. The susceptibility maps were calculated and verified for three different meteorological scenarios (given by three classes of snow depth). Verification has shown that the accuracy of the susceptibility maps was between 67% and 82%. The three susceptibility maps show a remarkable difference in the spatial pattern of the highest susceptibility pixels suggesting that for different meteorological scenarios different classes of terrain features need to be considered.The possibility to make combinations of terrain features and to assess and verify their statistical relationship with release areas of past avalanche events is the major original step made by STARTER. Linking those release areas to meteorological scenarios is an attempt to include in the analysis the combined influence of terrain features and meteorological conditions towards snowpack instability. 相似文献
17.
Patrick J. Kennelly A. James Stewart 《International journal of geographical information science》2014,28(2):383-406
Sky models are quantitative representations of natural luminance of the sky under various atmospheric conditions. They have been used extensively in studies of architectural design for nearly a century, and more recently for rendering objects in the field of computer graphics. The objectives of this paper are to (1) describe sky models, (2) demonstrate how map designers can render terrain under various sky models in a typical geographic information system (GIS), (3) illustrate potential enhancements to terrain renderings using sky models, and (4) discuss how sky models, with their well-established standards from a different discipline, might contribute to a virtual geographic environment (VGE).
Current GIS hill-shading tools use the Lambertian assumption which can be related to a simple point light source at an infinite distance to render terrain. General sky models allow the map designer to choose from a gamut of sky models standardized by the International Commission on Illumination (CIE). We present a computer application that allows the map designer to select a general sky model and to use existing GIS tools to illuminate any terrain under that model. The application determines the orientations and weights of many discrete point light sources that, in the aggregate, approximate the illumination provided by the chosen sky model. We discuss specific enhancements to terrains that are shaded and shadowed with these general sky models, including additional detail of secondary landforms with soft shadows and more realistic shading contrasts. We also illustrate how non-directional illumination models result in renderings that lack the perceptual relief effect. Additionally, we argue that this process of creating hill-shaded visualizations of terrain with sky models shows parallels to other geo-simulations, and that basing such work on standards from the computer graphics industry shows potential for its use in VGE. 相似文献
18.
POHCHIN LAI CHARLES F. GILLIES 《International journal of geographical information science》2013,27(2):241-251
Abstract The proliferation of digital cartographic and geographic information technologies has provided an obvious alternative to paper for the storage of maps. Not unlike their paper predecessors, digital maps must be indexed to provide sufficient access points to information and to allow the librarian carto-bibliographic control over the collection. Maps have traditionally been treated as ‘unusual’ books and librarians have relied primarily on cataloguing strategies designed for books. Most automated cataloguing efforts involve nothing more than the computerization of card catalogues without altering the nature and design of the task. This paper examines the utilities and unique qualities of cartographic materials and accounts for deficiencies of traditional cataloguing methods for the handling of both analogue and digital cartographic products. In view of the increased availability of digital cartographic databases, this paper also evaluates requirements and presents issues beyond the conventional responsibilities of spatial data librarianship. 相似文献
19.
基于多方位DEM地形晕渲的黄土地貌正负地形提取 总被引：5，自引：0，他引：5
以陕北绥德县韭园沟流域5 m分辨率DEM数据为基础,在数字地形分析、多元统计和数据挖掘方法的基础上,提出利用多方位DEM地形晕渲、坡度等多元指标,以主成分分析消除多重共线性和约减维数,并以Logis-tic回归模型提取黄土高原正、负地形的方法。研究结果表明:模型提取精度为82.1%,Kappa统计量为0.629;模型在6个不同流域测试样本上正、负地形的平均精度分别为77.6%,84.9%,加权平均精度为81.3%,模型具有较好的一致性和泛化能力,正、负地形提取效果良好。 相似文献
20.
Zsfia Ruszkiczay-Rüdiger Lszl Fodor Erzsbet Horvth Tams Telbisz 《Geomorphology》2009,104(3-4):203-217
The Gödöllő Hills, a low-relief terrain within the Central Pannonian Basin in Hungary, is characterised by moderate tectonic deformation rates. Although typical tectonic landforms are not clearly recognisable in the study area, this paper succeeded in discriminating between tectonically controlled landforms and features shaped by fluvial erosion or deflation with no tectonic control.DEM-based morphometric parameters including elevation, slope and surface roughness, enabled the delineation of two NW–SE trending spearhead-shaped ridges separated by a wide rectilinear valley of the same strike. Although directional statistics suggested possible tectonic control of NW–SE striking landforms, precise morphometry completed with an analysis of subsurface structures rejected their tectonic preformation. Deflation plays a significant role in shaping the area, and the presence of two large-scale yardangs separated by a wind channel is proposed. In temperate-continental areas of Europe, no deflational landforms of such scale have been described so far, suggesting that Pleistocene wind power in periglacial areas was more significant than it was previously thought.Characteristic drainage patterns and longitudinal valley profiles enabled the recognition of areas probably affected by neotectonic deformation. A good agreement was observed between locations of Quaternary warping predicted by the morphometric study and subsurface structures revealed by the tectonic analysis. Zones of surface uplift and subsidence corresponded to anticlinal and synclinal hinges of fault-related folds. In low-relief and slowly-deforming areas, where exogenous forces may override tectonic deformation, only the integrated application of morphometric and subsurface-structural indications could assure correct interpretation of the origin of various landforms, while a morphometric study alone could have led to misinterpretation of some morphometric indices apparently suggesting tectonic preformation. On the other hand, the described morphological expression of subsurface structures could verify Quaternary age of the deformation. 相似文献