共查询到20条相似文献,搜索用时 250 毫秒
1.
We examine some aspects related to the generation of the general-purpose landscape-assessment regional-typological 1:2 500 000 map for the Asian part of Russia that was initiated by the V. B. Sochava Institute of Geography SB RAS and is based on the methodological achievements of the theory of geosystems and landscape science in general as well as on results from regional comprehensive investigations. Presented are the fundamental principles of compiling the landscape-assessment map: the regional-typological approach, and reflection of the present state of invariant units of structure and ecologically functional significance for nature management. 相似文献
2.
An assessment is made of the uniqueness of modern vegetation in Prebaikalia as a biogeographical entity. It is shown that its complex structural-cenotic diversity is represented on the new universal geobotanical map of vegetation at a scale of 1:500 000. The map legend, constructed on the principles of V. B. Sochava’s multidimensional and multistage structural-dynamical classification of plant communities, displayed more than 160 cenotic subdivisions of vegetation of Prebaikalia representing its different types. An analysis is made of the development paths of vegetation for assessing its evolutionary potential. The study revealed the main stages of philocenogenesis in the Late Cainozoic. Its main directions have been revealed, which are important for understanding the characteristics of the region’s modern vegetation cover. The heterogeneity and heterochronicity of modern cenotic diversity of vegetation is shown. Emphasis is placed on the evolutionary processes of vegetation of Prebaikalia in the Holocene which can last for at least 40 thousand years. In this connection, it is proposed to change interpretation of the Holocene Optimum as an optimum for the evolution of the dark-coniferous taiga of Siberia. It is shown that the genetic linkages of the cenotic structure of modern vegetation cover in Prebaikalia are clearly pronounced via regional-typological categories of vegetation reflecting profound links of modern vegetation with natural-geographical regions where its philogenetic processes were taking place in interaction with the general evolution of the natural environment. An analysis is made of the significance of the floristic and cenotic boundaries having an important biogeographical significance. Such boundaries, on the one hand, are the footprint of the past evolutionary processes in vegetation, and in the natural environment as a whole, and, on the other, indicate the dynamical potential of possible changes in vegetation under global climate change. 相似文献
3.
We present a new approach of the Indirect Boundary Element Method (IBEM) for 3-D topographic problems which can be used to deal with an infinitely spread free surface owing to the introduction of a reference solution, that is the analytical solution for the half-space with a flat free surface. This approach is an efficient countermeasure for the non-physical waves owing to the domain truncation which contaminates the computed results in the ordinary approach. Theoretical consideration shows that this newly proposed approach is a higher-grade approximation than some existing ones and achieves a higher efficacy and accuracy than those of existing ones. The discretization of the resulting boundary integral equation for this formulation is carried out with triangular elements. Their contributions to the solution are calculated by Gaussian numerical integration except in the case where the wavefield is evaluated on the source element itself. For this case, we present an analytical formula based on the reasonable assumption that the elements are much smaller than the wavelengths appearing in the calculation. Several numerical examples used for validation show acceptably precise results. 相似文献
4.
Sarah-Patricia Breen 《社会与自然资源》2018,31(6):698-716
Rural regions face many challenges when managing drinking water systems. Current management approaches lack the ability to deal with the complexity that surrounds these infrastructure systems and the critical service they provide, in particular, the links between these systems and the economy and environment. This research explores the potential for an alternative approach. The proposed new regionalism-based approach recognizes and accounts for the myriad of influencing factors, using different mechanisms to support and encourage drinking water systems in fulfilling their potential role in supporting regional resilience. Using a case study approach, data collected from semistructured interviews indicate that elements of the proposed approach are already in use within the Kootenay Development Region of British Columbia, Canada. Results indicate that while the need for an alternate management approach is recognized, and elements of the proposed approach are increasingly applied, substantive barriers remain, such as the existing institutional and jurisdictional structure. 相似文献
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6.
基于DEM的地理要素PRISM空间内插研究 总被引:31,自引:7,他引:24
利用PRISM模型基于DEM、站点数据和其它空间数据图层内插了气象要素,以便准确表达其空间分布特征。为了比较PRISM空间内插结果,采用GIS常用的Kriging内插、Spline内插等方法分别对降水和气温站点数据进行空间插补,并对内插结果进行精度分析、DEM空间分辨率的影响分析和各个权重因子的影响分析。分析表明,PRISM方法比其它内插方法能够更加精确地表达气象要素的空间分布,更适合于在地形复杂地区地表参数的空间内插。由于气象要素空间分布的复杂性,PRISM内插方法不能完全表达地表参数空间异质性。以后研究中,应在更小的站点影响单元内考虑更多因子利用PRISM方法进行气象要素的空间内插。 相似文献
7.
资源环境模型库管理系统研究进展 总被引:3,自引:0,他引:3
资源环境模型库管理系统是资源环境研究中的关键问题之一。建立资源环境模型库管理 系统通常有两种途径。一种途径是采用模型管理技术, 其主要方法包括数据式模型管理、结构化 模型管理、面向对象的模型管理和基于知识的模型管理, 这种方式的优势是可以有效地管理资源 环境模型, 但对空间数据处理的功能较弱, 需要编写大量的程序代码。另一种途径是在GIS 中管 理模型, 如ArcGIS 中的ModelBuilder, 这种方式的优点是可以充分利用GIS 的空间数据处理能 力, 但对复杂模型的支持较差。根据以上两种方式的特点, 本文提出了一种面向对象的资源环境 模型管理框架, 把模型抽象为模型类与模型实例, 采用面向对象方法表达模型, 通过构建资源环 境模型引擎处理空间数据和模型数学方程; 利用模型库和数据库, 可以实现模型的有效管理和模 型重用。 相似文献
8.
Yiming Wang 《Norsk geografisk tidsskrift. Norwegian journal of geography》2018,72(3):161-175
Research on urban processes under capitalism and the resulting transformations of urban space is caught in a socio-spatial dualistic debate, which neglects the continuum and relativities of space. The author aims to extend this debate through an in-depth review and critique of the main perspectives on socio-spatial relations. He argues that in capitalist urban processes urban space plays a dual role as both the public sphere and arena of capital accumulation. However, importantly, this dual role has led to the multidimensional nature of the publicness of space which, in turn, collaboratively results in increasingly blurred boundaries between ‘public’ and ‘private’ in cities. To grapple with the new features of urban space for theory and empirical research, the article offers an alternative property rights approach. Rather than treating space as monolithic, the proposed property rights approach puts the case for analysing space as a continuum. On this basis, the author discusses how that approach can be used for empirical research. 相似文献
9.
Managing urban river channel adjustments 总被引:5,自引:2,他引:5
In managing river channels, awareness is increasing to acknowledge spatial patterns of channel adjustments, to adopt a holistic catchment perspective, to progress from hard to softer engineering methods, and to utilize a geomorphological approach. However, specific methods for analyzing urban channels have not been related to a management framework. Using Fountain Hills, AZ, as an example of an urbanizing area, this paper develops a dynamic approach for urban river channels that analyzes variations in channel adjustments in a spatial context. The approach requires methods for delineating the drainage network, for dividing the network into channel segments in the area investigated according to road crossings, and for categorizing and characterizing channel segments. Using stream channel hazards as a basis for characterizing channel segments, together with consideration of community views, this approach provides a potential framework for management as illustrated provisionally by indicating the most significant hazards that require management and then suggesting possible management options. 相似文献
10.
This paper describes the creation of two new geographical boundary files, known respectively as lower zones and upper zones, for investigating social phenomena and visualising disparities in health outcomes in the Auckland Region of New Zealand. We test the effectiveness of contemporary automated zone design tools before applying an interactive approach which integrated computational power with expert local knowledge and visual interpretation to develop meaningful zones. We demonstrate that an interactive approach addresses multiple zone design criteria (e.g. respecting physical barriers, compactness and homogeneity) more effectively than is possible with an automated approach. 相似文献
11.
A Bayesian approach to palaeoecological environmental reconstruction deriving from the unimodal responses generally exhibited
by organisms to an environmental gradient is described. The approach uses Bayesian model selection to calculate a collection
of probability-weighted, species-specific response curves (SRCs) for each taxon within a training set, with an explicit treatment
for zero abundances. These SRCs are used to reconstruct the environmental variable from sub-fossilised assemblages. The approach
enables a substantial increase in computational efficiency (several orders of magnitude) over existing Bayesian methodologies.
The model is developed from the Surface Water Acidification Programme (SWAP) training set and is demonstrated to exhibit comparable
predictive power to existing Weighted Averaging and Maximum Likelihood methodologies, though with improvements in bias; the
additional explanatory power of the Bayesian approach lies in an explicit calculation of uncertainty for each individual reconstruction.
The model is applied to reconstruct the Holocene acidification history of the Round Loch of Glenhead, including a reconstruction
of recent recovery derived from sediment trap data.
The Bayesian reconstructions display similar trends to conventional (Weighted Averaging Partial Least Squares) reconstructions
but provide a better reconstruction of extreme pH and are more sensitive to small changes in diatom assemblages. The validity
of the posteriors as an apparently meaningful representation of assemblage-specific uncertainty and the high computational
efficiency of the approach open up the possibility of highly constrained multiproxy reconstructions. 相似文献
12.
面向对象解译方法在遥感影像地物分类中的应用 总被引:9,自引:0,他引:9
针对高分辨率遥感影像快速高效萃取有用信息这一遥感技术应用的热点问题,探讨了基于面向对象(Object-oriented)解译方法的遥感影像自动及半自动解译和提取的新思路.文中分析了面向对象解译方法在地物信息分类应用中的优势,并提出了基于此方法的高分辨率遥感影像多尺度信息提取技术流程.具体结合广州市新白云机场开发区IKONOS高分辨率遥感数据进行地物快速提取、自动分类的试验,并对解译效果进行了评估分析,证明此方法在高分辨率遥感影像地物分类中确实高效可行. 相似文献
13.
Selective omission in a road network is a necessary operation for road network generalization. Most existing selective omission approaches involve one or two geometric parameters at a specific scale to determine which roads should be retained or eliminated. This study proposes an approach for determining the empirical threshold for such a parameter. The idea of the proposed approach is to first subdivide a large road network, and then to use appropriate threshold(s) obtained from one or several subdivisions to infer an appropriate threshold for the large one. A series of experiments was carried out to validate the proposed approach. Specifically, the road network data for New Zealand and Hong Kong at different scales (ranging from 1:50,000 to 1:250,000) were used as the experimental data, and subdivided according to different modes (i.e. administrative boundary data, a regular grid of different sizes, different update years, and different road network patterns). Not only geometric parameters, but also structural and hybrid parameters of existing selective omission approaches were involved in the testing. The experimental results show that although the most appropriate thresholds obtained from different subdivisions are not always the same, in most cases, the appropriate threshold ranges often overlap, especially for geometric parameters, and they also overlap with those obtained from the large road network data. This finding is consistent with the use of different subdivision modes, which verifies the effectiveness of the proposed approach. Several issues involving the use of the proposed approach are also addressed. 相似文献
14.
日本德川幕府时期的地缘环境分析——兼论国别地缘环境分析框架 总被引:6,自引:0,他引:6
自“地缘政治”一词创立以来,西方地缘政治学已经历了120年的发展,期间诞生了众多理论流派,然而其影响却在日渐衰落。这在一定程度上源于其发展思路以及由此导致对现实研究不足所致。中国地缘政治研究起步较晚,长期以借鉴西方地缘政治理论为主,直到2010年掀起以“地缘环境”研究为主题的复兴议程。地缘环境研究将地理知识和政治融入地缘政治分析过程中,这一研究方向与思路不仅有助于地缘政治研究的变革与创新,还有助于推进“一带一路”倡议和人类命运共同体建设,具有重要理论与现实意义。本文基于前期对有关地缘环境概念、构成、结构、模拟等内容的研究进展,提出了国别地缘环境研究思路、跨学科融合路径和分析框架,并以德川幕府时期的日本为例,展现了跨学科融合研究视角下日本受国内外多要素、长时间、多尺度综合作用所导致的地缘环境演变,对其中涉及到的日本对内、对外的政策制定与变化也从其面临的地缘环境视角进行了解读。最后为深化对当前国别地缘环境研究提出了三条建议。 相似文献
15.
Quantification of spatial gradation of slope positions 总被引:6,自引:0,他引:6
Cheng-Zhi Qin A-Xing Zhu Xun Shi Bao-Lin Li Tao Pei Cheng-Hu Zhou 《Geomorphology》2009,110(3-4):152-161
Transition between slope positions (e.g., ridge, shoulder slope, back slope, foot slope, and valley) is often gradual. Quantification of spatial transitions or spatial gradations between slope positions can increase the accuracy of terrain parameterization for geographical or ecological modeling, especially for digital soil mapping at a fine scale. Current models for characterizing the spatial gradation of slope positions based on a gridded DEM either focus solely on the parameter space or depend on too many rules defined by topographic attributes, which makes such approaches impractical. The typical locations of a slope position contain the characteristics of the slope position in both parameter space and spatial context. Thus, the spatial gradation of slope positions can be quantified by comparing terrain characteristics (spatial and parametrical) of given locations to those at typical locations. Based on this idea, this paper proposes an approach to quantifying the spatial gradation of slope positions by using typical locations as prototypes. This approach includes two parts: the first is to extract the typical locations of each slope position and treat them as the prototypes of this position; and the second is to compute the similarity between a given location and the prototypes based on both local topographic attributes and spatial context. The new approach characterizes slope position gradation in both the attribute domain (i.e., parameter space) and the spatial domain (i.e., geographic space) in an easy and practicable way. Applications show that the new approach can quantitatively describe spatial gradations among a set of slope positions. Comparison of spatial gradation of A-horizon sand percentages with the quantified spatial gradation of slope positions indicates that the latter reflects slope processes, confirming the effectiveness of the approach. The comparison of a soil subgroup map of the study area with the maximum similarity map derived from the approach also suggests that the quantified spatial gradation of slope position can be used to aid geographical modeling such as digital soil mapping. 相似文献
16.
用TM影像和DEM获取黑河流域地表反射率和反照率 总被引:28,自引:13,他引:15
传统的大气校正方法原理比较复杂,而且有些参数特别是实时的大气剖面资料难以获取。本文利用DEM对TM 影像进行地形校正后,用简便而又实用的方法对TM影像进行了大气校正,较精确地反演出黑河流域河西走廊中段对应于Landsat TM 1~5 和7波段的地表反射率。在此基础上,通过不同波段地表反射率的组合,获得了地表反照率。通过与实地观测数据对比分析,表明对于植被覆盖区用TM 2,4,7波段组合结果较好,而在非植被覆盖区用TM 1~5,7这6 个波段组合结果更佳。 相似文献
17.
Ibrahim Oztug Bildirici 《International journal of geographical information science》2013,27(12):2295-2309
Tissot’s indicatrix or ellipse of distortion is a diagram that is the projection of an infinitesimal circle on the original surface. It is normally an ellipse of which elongation depends on the amount of distortion caused by map projection. It provides a medium for analyzing existing projections and developing new ones. The ellipse can be scaled and depicted on the map for visualization purposes. This paper presents an alternative approach, in which the projection of a finite small circle on the sphere is used. Its projection is normally an ellipse that can be very close to Tissot’s indicatrix, and is called quasi indicatrix, here. Its parameters can be derived from the forward projection equations without using partial derivatives. Therefore, it is a useful and practical approach from a programmer’s point of view. The quasi indicatrix approach is also numerically tested on Aitoff–Hammer projection with a set of points. The indicatrix parameters obtained by using this approach deviate 0.5% from the ground truths at most, being the average less than 0.2%. 相似文献
18.
Sha Zhou Run Wang Junhua Ding Xiaofang Pan Fang Fang 《International journal of geographical information science》2019,33(9):1829-1846
During navigation, a pedestrian needs to recognize a landmark at a certain decision point. If a potential landmark located at a decision point is complicated to recognize, the complexity of the decision point is significantly increased. Thus, it is important to compute routes that avoid complicated decision points (CDPs) but still achieve optimal navigation performance. In this paper, we propose an approach for computing routes that avoid CDPs while optimizing the performance of landmark-based pedestrian navigation. The approach includes (1) a model for identifying CDPs based on the structures of pedestrian networks and landmark data in real scenes, and (2) a modified genetic algorithm for computing routes that avoid the identified CDPs and find the shortest route possible. To demonstrate the advantages and effectiveness of the proposed approach, we conducted an empirical study on the pedestrian network in a real-world scenario. The experimental results show that our approach can effectively avoid CDPs while still minimizing travel distance. Furthermore, our approach can provide the routes with the shortest travel distance if the distances of the routes without CDPs exceed a certain threshold. 相似文献
19.
Lucas Benedičič Felipe A. Cruz Tsuyoshi Hamada Peter Korošec 《International journal of geographical information science》2014,28(4):799-823
Geographical information systems are ideal candidates for the application of parallel programming techniques, mainly because they usually handle large data sets. To help us deal with complex calculations over such data sets, we investigated the performance constraints of a classic master–worker parallel paradigm over a message-passing communication model. To this end, we present a new approach that employs an external database in order to improve the calculation–communication overlap, thus reducing the idle times for the worker processes. The presented approach is implemented as part of a parallel radio-coverage prediction tool for the Geographic Resources Analysis Support System (GRASS) environment. The prediction calculation employs digital elevation models and land-usage data in order to analyze the radio coverage of a geographical area. We provide an extended analysis of the experimental results, which are based on real data from an Long Term Evolution (LTE) network currently deployed in Slovenia. Based on the results of the experiments, which were performed on a computer cluster, the new approach exhibits better scalability than the traditional master–worker approach. We successfully tackled real-world-sized data sets, while greatly reducing the processing time and saturating the hardware utilization. 相似文献
20.
Alan T. Murray Daoqin Tong 《International journal of geographical information science》2013,27(7):757-776
Facility placement and associated service coverage are major concerns in urban and regional planning. In this paper an approach is detailed for the problem of covering spatial demand for service, where potential facilities are located in the continuous plane. It is shown that weighted demand, represented as points, lines or polygons, can be optimally served by a finite number of potential facility locations, called the polygon intersection point set (PIPS). The developed approach is an extension of a point‐based abstraction of demand to more general representations (e.g. points, lines or polygons). An empirical analysis of warning siren siting in Ohio is carried out, highlighting the applicability of this approach. 相似文献