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1.
无人机在重大地质灾害应急调查中的应用   总被引:4,自引:0,他引:4  
传统的地质灾害应急调查受限于地形、天气等外界条件,不能快速全面地获取灾害的详细信息,而无人机具有灵活性强、时效性高和不受复杂地形影响等特点,在地质灾害应急调查中有独特的优势。本文以“6·24”新磨村滑坡和“10·11”白格滑坡为例,阐述了无人机数据获取及处理流程,重点介绍了无人机获取的数字地形产品在地质灾害精确描述、定性及定量分析中的应用。结果表明:无人机摄影测量技术为重大地质灾害应急调查提供了更加科学高效的现场影像采集和遥感成果处理及应用方案,为应急救灾工作的顺利实施及分析研判提供了重要数据支撑,科学有效地保证了现场施工救援人员的安全。  相似文献   

2.
In a critique of maps used for geomorphological research (too cluttered to be read effectively, too general in respect to contour positioning), the author describes: (a) a methodology whereby conventional hypsometric maps can be corrected through the use of air photos, (b) outlines principles for symbol generalization and selection whereby the amount of geomorphological information perceived on hypsometric maps is increased, and (c) recommends the joint use of hypsometric, topographic photo-, and general geomorphological maps as the most effective means of terrain analysis. Translated by Larry Richardson, Glendale, CA 91202 from: Geomorfologiya, 1991, No. 2, pp. 38–45.  相似文献   

3.
The authors attempt to identify and standardize the cartographic symbols (“images”) used to represent a variety of specific geomorphological features. A large number of cartographic representations of landform features found on geological-geomorphological maps are classified in terms of their basic pattern/configuration and the level of complexity within each major pattern type. It is argued that the pattern or configuration of a cartographic symbol used to represent a geomorphological feature should represent the spatial structure of that feature with sufficient reliability to serve as a key to an understanding of its genesis. Translated from: Geomorfologiya, 1987, No. 2, pp. 62-66.  相似文献   

4.
Work is reported on the production of terrain elevation data from SPOT imagery. An important step in this process is determination of exterior orientation parameters for the images. Although an initial estimate is available in the SPOT header, refinements are required based on plan and height data. These are generally derived from photogrammetric measurements (or sources such as global positioning satellite systems), but accurate manual determination is time consuming. This paper reports an alternative approach by investigating the use of existing map data (located on the earth's surface and in a known projection) to find corresponding “ground control points” in both map and image. Available maps may be in digital or paper form depending on the state of development of mapping in the part of the world being studied. The last revision date and the cartographic generalisation employed will also effect the fidelity of the final result. Practical semi-automatic techniques for determining the height of ground control points from existing map data are described, including multiple profiles through digitised contour data, a commercial terrain modelling package based on Delaunay triangulation and the use of triangulation points on prominent features. Comparisons between the methods are made and results obtained are compared with Institut Géographique National datasets and photogrammetric measurements. Methods for fully automating not only the height determination but also the location of ground control features within a map database are discussed. Map and image registration is described and illustrated using Laser-Scan's Rover software. Interactive and automated methods of registration are discussed.  相似文献   

5.
6.
晕渲图的设计与制作一直是地学工作者研究的热点问题,使用晕渲图展示地形直观、形象、立体感强.目前有多种思路被提出用于改善晕渲图的显示效果,但是在制作小比例尺晕渲图时,仍然存在一些问题,如地形破碎导致难以把握地形宏观骨架,缺少海洋地形或海洋地形过于具体干扰到陆地要素表达,传统的DEM与山影数据叠加的模式使得美观与地形清晰无法兼得,这就需要重新对这些问题进行思考.本文以晕渲图的基本理论为出发点,采用地貌晕渲与分层设色相结合的方法,讨论全球范围的晕渲图制作过程中,不同显示比例尺下DEM分辨率配置技巧、海洋地形展示方法与地形可视化新思路.实验证明,该方法可以保证晕渲图在每级显示比例尺下都能展示出良好的地形效果,为中小比例尺晕渲图增强表现力提供了参考.  相似文献   

7.
The paper describes a method for the compilation of isarithmic maps of average annual runoff for a waterlogged taiga area in West Siberia using computer algorithms. Considerable attention is devoted to such methodological issues as isarithm interpolation; determining what constitutes an adequate number of control points; and utilization of spline functions, “sieving” points, and piecewise-linear modeling. Spline-functions more precisely and reliably describe the field of annual runoff. Translated by Larry Richardson, Glendale, CA 91202 from: Geografiya i prirodnyye resursy, 1993, No. 3, pp. 20-26.  相似文献   

8.
The author defines cartographic space, i.e., the space encompassed by geographic maps, as the entire “geographic” envelope. Maps as spatial models of the concrete three-dimensional space of this envelope [increasingly this space is viewed as four-dimensional, when the element of time is included] depict geosystems of various levels and complexity and serve as an essential basis for analyzing their properties, internal processes, and relationships. The author argues against divorcing the study of cartographic space from an understanding of the content of the objects being mapped, and critically evaluates positions of other Soviet and East European cartographers on the “dual role” of the cartographic space of maps. Translated from: Vestnik Moskovskogo Universiteta, geografiya, 1986, No. 2, pp. 3-9.  相似文献   

9.
A survey of the use of topologic concepts of space in map transofrmation supports the author's contention that so-called “transformed images” represent for the most part rather arbitrary distortions of conventional maps constructed in Euclidean space. This paper demonstrates how truly topologic images can be created “from scratch,” i.e., without manipulation of either the sizes or shapes of areal units on preexisting maps. Images created by quantitatively defining “graphic ratios” of areal units can thus be replicated by other cartographers with a minimum of subjectivity. Translated from: Geodeziya i kartografiya, 1984, No. 12, pp. 28-31.  相似文献   

10.
Generalization of DEM for terrain analysis using a compound method   总被引:5,自引:0,他引:5  
This paper reports an investigation into the generalization of a grid-based digital elevation model (DEM) for the purpose of terrain analysis. The focus is on the method of restructuring the grid-based surface elevation data to form a triangulated irregular network (TIN) that is optimized to keep the important terrain features and slope morphology with the minimum number of sample points. The critical points of the terrain surface are extracted from the DEM based on their significance, measured not only by their local relief, but also by their importance in identifying inherent geomorphological and drainage features in the DEM. A compound method is proposed by integrating the traditional point-additive and feature-point methods to construct a drainage-constrained TIN. The outcome is then compared with those derived from other selected methods including filtering, point-additive or feature-point algorithms. The results show that the compound approach is capable of taking advantage of both point-additive and feature-point algorithms to maximally keep the terrain features and to maintain RMSE at an acceptable level, while reducing the elevation data points by over 99%. The analytical result also shows that the proposed method outperforms the compared methods with better control in retaining drainage features at the same level of RMSE.  相似文献   

11.
A procedure is described for the revision of digital maps in geographic information systems, the basis of which rests upon a “mutual and unambiguous correspondence” between a digital map and its structural (text or graphic) model(s). Rules of transference, editing, elimination, inclusion, and cross-referencing of names are elaborated for regulation of the processes by which non-digital (cartographic, air photo, statistical) sources of new information are used to transform digital information in the original data base. Revision of digital maps is accomplished through creation of a data base of digital corrections to an original data base and/or subsequent editing of digital map(s) from these corrections or others initiated during raster scanning. Translated from: Geodeziya i kartografiya, 1986, No. 9, pp. 38-43.  相似文献   

12.
A raster and vector GIS was created for the North Appalachian Experimental Watershed (NAEW) from legacy (1960) 1:2,400‐scale contour maps. The intent of the study was to use terrain data for the spatial modeling of soil organic carbon. It was hypothesized that DEMs derived from these data would be more accurate and therefore more useful for terrain‐based soil modeling than those from USGS 1:24,000‐scale contour data. Central tasks for this study were to digitally capture the 1:2,400‐scale maps, convert digital contour data sources to raster DEMs at multiple resolutions, and derive terrain attributes. A flexible approach was adopted, using software outside of mainstream GIS sources where scientifically or practically advantageous. Elevation contours and streamlines were converted to raster DEMs using ANUDEM. DEMs ranging in resolution from 0.5–30 m were tested for accuracy against precision carrier‐phase GPS data. The residual standard deviation was 1.68 meters for the USGS DEM and 0.36 meters for the NAEW DEM. The optimal horizontal resolution for the NAEW DEM was 5 m and for the USGS 10 m. Five and 10 m resolution DEMs from both data sources were tested for carbon prediction. Multiple terrain parameters were derived as proxies for surficial processes. Soil samples (n = 184) were collected on four zero‐order watersheds (conventional tillage, no‐till, hay and pasture). Multiple least squares regressions (m.l.s.) were used to predict mass C (kg m?2, 30 cm depth) from topographic information. Model residuals were not spatially autocorrelated. Statistically significant topographic parameters were attained most consistently from the 5 m NAEW DEM. However, topography was not a strong predictor of carbon for these watersheds, with r2 ranging from 0.23 to 0.58.  相似文献   

13.
Topographic maps and aerial photographs are particularly useful when geoscientists are faced with fieldwork tasks such as selecting paths for observation, establishing sampling schemes, or defining field regions. These types of images are crucial in bedrock geologic mapping, a cognitively complex field-based problem-solving task. Geologic mapping requires the geologist to correctly identify rock types and three-dimensional bedrock structures from often partial or poor-quality outcrop data while navigating through unfamiliar terrain. This paper compares the walked routes of novice to expert geologists working in the field (n = 66) with the results of a route planning and navigation survey of a similar population of geologists (n = 77). Results show clearly that those geologists with previous mapping experience make quick and decisive determinations about field areas from available imagery and maps, regardless of whether they are or not physically present in the field area. Recognition of geologic features enabled experts to form and verbalize a specific plan for travel through a landscape based on those features. Novices were less likely to develop specific travel route plans and were less likely to identify critical landscape cues from aerial photographs.  相似文献   

14.
The traditional approach to geologic mapping consists of sketching, taking orientation and thickness measurements with compass and tape, and noting positions of features on topographic maps or photos. These methods are time consuming, often difficult to realize in rough terrain, and poorly constrain lateral variations in sedimentary facies in relatively flat lying strata. We describe a case study that captures the three-dimensional architecture of sandstone bodies and key geological surfaces such as stratigraphic boundaries and faults using digital capture techniques. The Ferron sandstone in Utah is a superbly exposed ancient delta deposit that provides an improtant outcrop analog to fluvio-deltaic subsurface reservoirs. It has been the focus of many traditional outcrop studies, but here we use a methodology (“cybermapping”) based on GPS with offsets from a continuous ranging mode reflectorless laser rangefinder (“laser sketch”) for collection and analysis of basic stratigraphic and structural data in a relatively remote area. We also show hos this data can be analyzed and visualized in three dimensions. The study area was mapped in two days, which included hiking several kilometers into the area. One-the-fly and rapid static post processing of GPS surveying was used for positioning the reflectorness laser rangefinders; 60,000 points were acquired mapping sedimentological and structural features, terrain, and control points. The resultant quantitative 3D model of the geology and terrain allowed robust geometric visualization and analyses. ? 2001 John Wiley & Sons, Inc.  相似文献   

15.
Algorithms, designed for digital image processing in standard mainframe computers and representing sequential stages in a land-use classification procedure, are used to produce maps of agricultural crop types from multispectral satellite imagery. Pixel reflectance values are first grouped according to an unsupervised “rapid classification algorithm,” or data compression procedure. Mean reflectance values of the resulting classes then go into a supervised “sequential clustering algorithm” where classes are refined according to training value and other parameter inputs. The objective is to increase the accessibility of automated image interpretation while balancing classification accuracy and processing time. Translated from: Vestnik Moskovskogo Universiteta, geografiya, 1984, No. 4, pp. 63-69.  相似文献   

16.
This paper explores applications of digital photogrammetric modeling of mountainous terrain in forecasting snow depth and the meltwater avalanche hazard in a mining region of northwestern Russia. A series of initial maps (initial terrain points, relief of snow-flow centers, slope angles and orientations) provides successively more specific information, culminating in the compilation of a map of maximum snow cover depths at a center of water-saturated snow flows (representative reference site) on the northern slope of Mt. Aykuayvenchorr. Translated by Edward Torrey, Alexandria, VA 22308 from: Geomorfologiya, 1993, No. 3, pp. 75-83.  相似文献   

17.
Digital Elevation Models (DEMs) and their derivatives are routinely exploited for a wide range of planning and engineering applications such as land reclamation, calculation of cut-and-fill requirements for earth works or to determine other relevant geomorphological landscape parameters. The advent of computer (digital) manipulation of elevation data has opened up great possibilities for studying the geometry of our land surface in relation to physical factors such as climate, vegetation, soils and geology. This paper is concerned with the generation, testing and validation of DEM and its derived terrain parameters viz., contours, drainage pattern etc. using IRS-1C stereo pair over a part of Alwar district, Rajasthan, India. In particular, it reports on the results achieved using indigenously developed stereo - processing software along with standard GIS and terrain analysis package to derive DEM and associated terrain parameters of the study area. The results are encouraging when compared with Survey of India topographical maps at 1:50,000 scale in terms of point to point accuracy of DEM, data quality evaluation of orthoimage and higher order drainage delineation.  相似文献   

18.
An article devoted to applied forest-fire mapping outlines principles for the compilation of maps depicting “raw materials” for such fires. Various types and densities of vegetation cover are classified in terms of combustibility, i.e., according to the intensity of burning expected once they are fully exposed to flames. These maps are used in conjunction with weather data and forecasts to predict and combat the spread of fire across an area. Particular attention is devoted to identification and mapping of “basic conductors” of combustion–layers of forest litter and mossypeaty vegetation along which a forest fire normally spreads. Translated from: Geografiya i prirodnyye resursy, 1987, No. 3, pp. 138-144.  相似文献   

19.
提出了一种山地区域基于DEM地性线的控制纠正新方法,该方法以数字地形模型DEM为无几何变形的控制基准纠正卫星影像。阐述了提取沟谷、山脊、山峰和凹地区域的地性线的原理和算法,给出了山地区域基于地性线进行卫星图像几何精纠正实施步骤,进一步讨论了地性线提取、控制点采集存在的问题,以及解决问题的途径。实验结果表明,对于山地区域,地性线的空间数量数倍于水系、道路等常规地图层;地性线来源于DEM,其空间稳定性和可靠性更高,可以用于山地区域的卫星影像的严格控制纠正。用该方法进行几何纠正处理,几何误差能控制在一个像元的水平上。  相似文献   

20.
A review of basic theoretical principles of “ecological” mapping and types of maps of the environment sets the stage for a more detailed treatment of ecological-geographic maps—maps portraying a wide range of nature-society and nature-nature relationships—as they are used in support of economic development and environmental monitoring in Siberia. Particular attention is devoted to the compilation of map series, which include ecological-geographical maps, for the Lake Baykal area, BAM service zone, West Siberia, and specific territorial production complexes (e.g., Kansk-Achinsk TPC). Translated from: Geografiya i prirodnyye resursy, 1987, No. 3, pp. 10-18.  相似文献   

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