共查询到20条相似文献，搜索用时 929 毫秒
1.
DEM 点位地形信息量化模型研究 总被引：2，自引：0，他引：2
针对DEM 点位, 首先应用微分几何法对其所负载的语法信息量进行测度, 其次根据地形特征点类型及地形结构特征确定其语义信息量, 然后基于信息学理论构建了DEM 点位地形信息综合量化模型。在此基础上, 以黄土丘陵沟壑区作为实验样区, 对DEM 点位地形信息量提取方法及其在地形简化中的初步实例应用进行了探讨和验证。实验结果显示, 所提出的DEM 点位地形信息量化方案可行;基于DEM 地形信息量指数的多尺度DEM 构建方案, 具有机理明确、易于实现的特点, 并通过优先保留地形骨架特征点, 可以有效减少地形失真, 从而满足不同层次的多尺度数字地形建模和表达要求。对DEM 点位地形信息进行有效量化, 为认识DEM 地形信息特征提供了一个新的切入点, 同时为多尺度数字地形建模提供理论依据与方法支持。 相似文献
2.
DEM综合是其描述的地形表面细节逐渐舍去、轮廓不断呈现的连续过程。该文运用小波变换和方根模型模拟这一过程,将小波高频系数作为DEM综合的对象,以方根模型作为阈值设定的理论依据,对小波分解各层按不同等级进行取舍实现DEM综合。以1∶1万地形图建立的DEM进行试验,派生一系列不同复杂度的DEM,并用等高线分布特征、坡度和剖面曲率、地形叠加等进行对比分析。结果表明,随着DEM综合程度增大,生成的DEM逐步舍去地形表面细节,同时较好保持了原DEM山体轮廓、山脊和谷地的走向等地貌形态特征。最后,运用回归分析方法建立了派生DEM与相应空间分辨率之间的关系,为DEM尺度效应的应用提供方法和数据支持。 相似文献
3.
A digital elevation model (DEM), which is used to represent a terrain surface, is normally constructed by applying an interpolation method on given sample elevation points. Interpolation methods can be classified into two classes: linear methods, which have a low time cost and are suitable for terrains where there is little change in elevation, and nonlinear methods, which normally consume comparatively more time and are more suitable for terrains where there are frequent changes in elevation. A hybrid interpolation method, which involves both a linear method and a nonlinear method of interpolation, is proposed in this paper. The proposed method aims to integrate the advantages of both linear and nonlinear interpolation methods for the refinement of regular grid DEM. Here, the bilinear is identified as the linear method, and the bi‐cubic is taken to be the nonlinear interpolation method. The hybrid method is an integration of a linear model and nonlinear interpolation model with a parameter that defines the weights for each of the models. The parameter is dependent on the complexity of the terrain, for which a DEM is to be interpolated. The experimental results in this study demonstrate that the hybrid method is effective for interpolating DEMs for various types of terrain. 相似文献
4.
DEM内插方法与可视性分析结果的相似性研究 总被引：2，自引：0，他引：2
以实际采样的散点数据为原始数据,利用反距离权、样条函数、克里格、自然邻点内插、TIN内插5种内插方法生成规则格网DEM,并对其可视性分析结果进行对比分析和相关分析,揭示不同内插方法对可视性分析结果的影响规律和可视性分析对内插方法的敏感程度。结果表明,可视性分析对内插方法比较敏感,不同的内插方法会得到不同的可视性分析结果,其中相关程度最强的是样条函数内插和克里格内插、自然邻点内插和TIN内插。 相似文献
5.
地形元素（如山脊、沟谷等）是地表形态类型基本单元,通过地形元素的不同空间组合可形成更高级别的地貌类型。现有的地形元素提取方法大多依靠地形属性计算,难以克服地形元素的空间相关性表达与局部地形属性计算存在不对应的矛盾,Jasiewicz和Stepinski提出的Geomorphons方法——基于高程相对差异信息进行地形元素分类,可避免这一问题,但Geomorphons方法本质上是在单一分析尺度上选择地形特征点用于判别,易受局部地形起伏的影响而造成误分类。针对这一问题,设计出一种多分析尺度下综合判别的地形元素分类方法。应用结果表明：相比Geomorphons方法,利用该方法得到的地形元素的分类结果更为合理。 相似文献
6.
数字地形分析的理论、方法与应用 总被引：17，自引：2，他引：15
数字高程模型自20世纪50年代首次被提出以来,就以其简洁的数据组织方式、对地形的直观表达、简单高效的地形因子解译方法而显示了其在地学领域应用的巨大潜力。本文在全面检索和分析前人相关研究成果的基础上,首先将数字地形分析 (Digital Terrain Analysis,简称DTA) 的各种分析方法总结为四类,即坡面地形因子分析、特征地形要素分析、地形统计分析以及基于DEM的地学模型分析,并简要总结了每种分析方法的主要内容;其次,探讨了数字地形分析的精度及尺度问题,指出尺度效应、最适宜尺度选择以及尺度转换是DEM地形分析中的基本尺度问题;然后,论文介绍了DTA在地貌、水文、土壤、地质灾害、农业等领域的应用现状;最后,提出了数字地形分析发展方向,指出数字地形分析的概念框架亟待完善、模型构建精度有待提高、地形分析方法需要扩展,尤其是实现DEM模型嵌入的一体化分析方法,以求得到与现实世界地理环境更为接近的模拟。 相似文献
7.
Digital terrain analysis(DTA) is one of the most important contents in the research of geographical information science(GIS). However, on the basis of the digital elevation model(DEM), many problems exist in the current research of DTA in geomorphological studies. For instance, the current DTA research appears to be focused more on morphology, phenomenon, and modern surface rather than mechanism, process, and underlying terrain. The current DTA research needs to be urgently transformed from the study of landform morphology to one focusing on landform process and mechanism. On this basis, this study summarizes the current research status of geomorphology-oriented DTA and systematically reviews and analyzes the research about the knowledge of geomorphological ontology, terrain modeling, terrain derivative calculation, and terrain analytical methods. With the help of DEM data, DTA research has the advantage of carrying out geomorphological studies from the perspective of surface morphology. However, the study of DTA has inherent defects in terms of data expression and analytic patterns. Thus, breakthroughs in basic theories and key technologies are necessary. Moreover, scholars need to realize that DTA research must be transformed from phenomenon to mechanism, from morphology to process, and from terrain to landform. At present, the research development of earth science has reached the critical stage in which the DTA research should focus more on geomorphological ontology. Consequently, this study proposes several prospects of geomorphology-oriented DTA from the aspects of value-added DEM data model, terrain derivatives and their spatial relations, and macro-terrain analysis. The study of DTA based on DEM is at a critical period along with the issue on whether the current GIS technology can truly support the development of geography. The research idea of geomorphology-oriented DTA is expected to be an important exploration and practice in the field of GIS. 相似文献
8.
TANG Guo-an~ Josef Strobl~ GONG Jian-ya~ ZHAO Mu-dan~ CHEN Zhen-jiang~ 《地理学报(英文版)》2001,11(2):209-216
1 IntroductionDigital elevation model (DEM) is digital representation of relief. It is one of the most important components in the database of GIS. At present, DEM is playing a key role in the field of survey and mapping, remote sensing and almost all the terrain related geographical analyses. DEM can be grouped into regular grids (raster) and triangulated irregular networks (TIN). Both have their advantages and disadvantages in application. It is generally believed that grid DEM will … 相似文献
9.
There is a growing interest in investigating the accuracy of digital elevation model (DEM). However people usually have an unbalanced view on DEM errors. They emphasize DEM sampling errors, but ignore the impact of DEM resolution and terrain roughness on the accuracy of terrain representation. This research puts forward the concept of DEM terrain representation error (Et) and then investigates the generation, factors, measurement and simulation of DEM terrain representation errors. A multi-resolution and multi-relief comparative approach is used as the major methodology in this research. The experiment reveals a quantitative relationship between the error and the variation of resolution and terrain roughness at a global level. Root mean square error (RMS Et) is regressed against surface profile curvature (V) and DEM resolution (R) at 10 resolution levels. It is found that the RMS Et may be expressed as RMS Et = (0.0061 × V+ 0.0052) × R - 0.022 × V + 0.2415. This result may be very useful in forecasting DEM accuracy, as well as in determining the DEM resolution related to the accuracy requirement of particular application. 相似文献
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11.
面向地貌学本源的数字地形分析研究进展与展望 总被引：5，自引：2，他引：3
数字地形分析（DTA）是地理信息科学（GIS）研究的热点。但是,当前基于数字高程模型（DEM）的数字地形分析在地貌学研究中存在重形态轻机理、重现象轻过程、重地上轻地下等问题,急需从单一的地貌形态分析,迈向面向成因、过程与机理等地貌学本源问题的研究转变。据此,本文系统梳理了面向地貌学本源的数字地形分析的相关研究现状,并从地貌学本源认识、地貌形态建模、地形因子提取、以及其他地形分析方法等研究进行了系统的回顾、梳理与分析。研究表明,基于DEM的数字地形分析虽具有地貌特征分析的潜力与优势,但是,数字地形分析存在数据表达与分析模式上的先天缺陷,亟待通过基础理论与关键技术的突破,实现理论与方法的创新发展,实现从“坡面”走向“区域”,从“形态”走向“过程”,从“地形”走向“地貌”。而当今地球系统科学的研究发展态势也到了数字地形分析研究从重视地貌形态走向揭示地貌学本源的关键阶段。因此,本文从DEM数据模型增值、地形因子及其地形空间关系、以及宏观地形分析等侧面展望了面向地貌学本源的数字地形分析研究。当今基于DEM的数字地形分析研究,正像当前的GIS是否能够真正支撑地理学发展一样,已经处于一个非常关键的十字路口。面向地貌学本源的数字地形分析研究思路可望成为地理信息科学领域理论与方法创新的一次重要探索与实践。 相似文献
12.
基于GIS的斜坡单元划分方法改进与实现 总被引：5，自引：0，他引：5
斜坡单元已广泛应用于滑坡易发性制图和地质灾害评价。然而在山间盆地或大型宽谷处,常规方法划分出的斜坡单元与地貌背景难以匹配。依据高程及其衍生变量的基本形态系统和曲率的流域分割原理,基于ArcGIS技术,通过叠加曲率和反转曲率的流域边界,改进了斜坡单元划分方法。结果表明：与常规方法相比,改进方法不仅能够使用山脊线和山谷线以划分斜坡单元,还能利用台地边界和宽谷边界以分割水平地表与倾斜地表;划分出的单元大小相对均匀,单元形状总体介于圆形和正三角形之间。对于水平成分较多的地区,如黄土塬区和水库库区,该方法与传统方法相比,具有较好的应用前景。 相似文献
13.
Patrik Krebs Markus Stocker Gianni Boris Pezzatti Marco Conedera 《International journal of geographical information science》2013,27(4):643-666
Terrain curvature is one of the most important parameters of land surface topography. Well-established methods used in its measurement compute an index of plan or profile curvature for every single cell of a digital elevation model (DEM). The interpretation of these outputs may be delicate, especially when selected locations have to be analyzed. Furthermore, they involve a high level of simplification, contrasting with the complex and multiscalar nature of the surface curvature itself. In this paper, we present a new method to assess vertical transverse and profile curvature combining real-scale visualization and the possibility to measure these two terrain derivatives over a large range of scales. To this purpose, we implemented a GIS tool that extracts longitudinal and transverse elevation profiles from a high-resolution DEM. The performance of our approach was compared with some of the most commonly used methods (ArcMap, Redlands, CA, USA; ArcSIE, Landserf) by analyzing the terrain curvature around charcoal production sites in southern Switzerland. The different methods produced comparable results. While conventional methods quickly summarize terrain curvature in the form of a matrix of values, they involve a loss of information. The advantage of the new method lies in the possibility to measure and visualize the shape and size of the curvature, and to obtain a realistic representation of the average curvature for different subsets of spatial points. Moreover, the new method makes it possible to control the conditions in which the index of curvature is calculated. 相似文献
14.
Jozef Minár Marián Jenčo Ian S. Evans Jozef Minár Jr. Martin Kadlec Jozef Krcho 《International journal of geographical information science》2013,27(7):1381-1402
Third-order geomorphometric variables (based on third derivatives of the altitudinal field) have been neglected in geomorphometry, but their application to the delimitation of surface objects will lead to their increasing significance in future. New techniques of computation, presented and evaluated here, facilitate their use. This paper summarizes recent knowledge concerning definition, computation and geomorphologic interpretation of these variables. Formulae defining various third-order variables are unified based on the physical definition of slope gradient. Methods for their computation are compared from the point of view of method error and error generated by digital elevation model (DEM) inaccuracy. For exact mathematical test surfaces, the most natural and simple variant of the method of central differences (CD2) shows a method error 2–3 times smaller than the other methods used recently in geomorphometry. However, success in coping with DEM inaccuracy depends (for a given grid mesh) on the number and weighting of points from which the derivative is computed. This was tested for surfaces with varying degrees of random error. Here least squares-based methods are the most effective for mixed derivatives (especially for finer grids and less accurate DEMs), while a variant of the CD method, that repeats numerical evaluation of first derivatives (CD1), is the most successful for derivatives in cardinal directions. The CD2 method is generally the most successful for coarser grids where the method error is dominant. Utilization of third-order variables is documented from examples of terrain feature (ridge, valley and edge) extraction and from a first statistical test of the hypothesis that real segments of the land surface have a tendency to a constant value of some morphometric variable. For detection of (sharp) ridges and valleys, it is shown that the rate of change of tangential curvature is inadequate: rate of change of normal curvature is also required. A basic confirmation of the constant-value tendency is provided. 相似文献
15.
地理对象的空间展布格局特征是区域地貌研究的核心问题.其中,把握地物的组织结构及尺度范围特征是认识其空间展布格局的根本.选取黄土丘陵沟壑区韭园沟流域为实验样区,以流域地形特征线为切入点,采用空隙度系列分析方法,在5 m分辨率DEM上研究黄土地貌发育中期小流域内,地形谷脊线的空间展布格局特征.在东-西、南-北两个方向的探测结果表明:韭园沟流域谷、脊线均具有自组织、多尺度、自相似的格局特点,但各向异性特征不明显.在两个方向上均具有三个特征尺度范围:在东西方向上尺度范围分别为540 m、2 100 m、4 845 m;南北方向上尺度范围分别为1 215 m、2 810 m、5 700 m.该研究结果初步揭示了黄土地貌流域系统骨架线的空间展布格局特征,为区域地貌研究时分析尺度的选取,提供了可借鉴的思路与方法. 相似文献
16.
I. V. Florinsky A. N. Pankratov 《International journal of geographical information science》2016,30(12):2506-2528
There are three major mathematical problems in digital terrain analysis: (1) interpolation of digital elevation models (DEMs); (2) DEM generalization and denoising; and (3) computation of morphometric variables through calculating partial derivatives of elevation. Traditionally, these three problems are solved separately by means of procedures implemented in different methods and algorithms. In this article, we present a universal spectral analytical method based on high-order orthogonal expansions using the Chebyshev polynomials of the first kind with the subsequent Fejér summation. The method is intended for the processing of regularly spaced DEMs within a single framework including DEM global approximation, denoising, generalization, as well as calculating the partial derivatives of elevation and local morphometric variables.
The method is exemplified by a portion of the Great Rift Valley and central Kenyan highlands. A DEM of this territory (the matrix 480 × 481 with a grid spacing of 30″) was extracted from the global DEM SRTM30_PLUS. We evaluated various sets of expansion coefficients (up to 7000) to approximate and reconstruct DEMs with and without the Fejér summation. Digital models of horizontal and vertical curvatures were computed using the first and second partial derivatives of elevation derived from the reconstructed DEMs. To evaluate the approximation accuracy, digital models of residuals (differences between the reconstructed DEMs and the initial one) were calculated. The test results demonstrated that the method is characterized by a good performance (i.e., a distinct monotonic convergence of the approximation) and a high speed of data processing. The method can become an effective alternative to common techniques of DEM processing. 相似文献
17.
在研究地形多分辨率细节层次模型构建理论的基础上,提出了结合地形特征的模型细节层次的细分过程,改进了基于外存的数据存储设计方法。设计了基于增量段式存储的数据组织方式,研究了地形数据绘制过程中的裂缝现象,引入模型高度损失误差计算方法,通过采用增删高程点的办法,消除了绘制图形中的裂缝。以某地区的DEM数据为实验数据,采用C++和OpenGL编程实现了地形的绘制。结果表明：本存储策略优于传统存储策略,通过增量段式的形式存储不同分辨率的高程点,重叠的高程值不再重复存储,以节约外存空间,减少了数据冗余度,I/O操作时间提高率为25%。且随着数据量增加,I/O操作时间提高效率更为显著。该存储设计将物理分块、逻辑分层、索引检索方法结合在一起使用,在减少外存占用率、降低数据量加载的同时,也提高了数据扩展的灵活性。当增加地形分块时,不会影响原有分块和存储结构。实验效果与原始地形非常相似,保证了生成的细节层次模型的真实性。此外,针对DEM实验数据,在加载非相邻分辨率等级层次的数据时,地形绘制过程出现裂缝的问题,通过删除高程点的办法来消除裂缝,取得了很好的实验效果。 相似文献
18.
基于SPIHT小波的DEM自适应压缩方法研究 总被引：1，自引：0，他引：1
海量地形数据给其存储、分发和实时渲染带来了极大的挑战,因此迫切需要适合网络环境下地形可视化的数据压缩方法。该文探讨地形复杂度与DEM压缩方法的关系,研究可视化中地形复杂度的计算方法,并提出一种改进的SPIHT小波压缩方法:采用小波分解后的系数对DEM的地形复杂度进行评估,并针对地形复杂度对编码算法进行自适应调节。实验证明,这种改进的SPIHT小波压缩方法采用合适的压缩比进行DEM数据压缩,能够在满足地形可视化需要的同时提高压缩效率。 相似文献
19.
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
20.
等高线曲率是一个重要的地形属性，反应了地形表面在水平方向的凹凸性，表达了地表物质运动的发散和汇合模式。基于安塞县县南沟小流域的矢量等高线数据和DEM，分别利用圆拟合算法（相邻三点法、间隔三点法和最小二乘法）和曲面拟合模型（E模型、S模型和Z模型）提取等高线曲率，通过对实地地形的对比分析，结果表明：（1） 在矢量等高线数据的计算结果中，三点拟合法计算结果相比最小二乘法结果差异大，对等高线曲率空间格局分布描述更准确；（2） 最小二乘法计算的结果频数分布集中程度最高，两种三点拟合法计算结果频数曲线差别微小；（3） 在栅格数字高程模型的计算结果中，基于S模型计算结果在空间格局上较E模型和Z模型的结果差别大，基于E模型的计算结果对等高线曲率描述效果更好。结果能准确说明采用不同算法计算等高线曲率的差别，对在实际数字地形分析中有重要的意义，可为等高线曲率计算提供重要参考。 相似文献