共查询到20条相似文献，搜索用时 15 毫秒
1.
Sunghwan Cho M. Xavier Punithan Jonggun Gim 《International journal of geographical information science》2014,28(12):2533-2550
In spatial data sets, gaps or overlaps among features are frequently found in spatial tessellations due to the non-abutting edges with adjacent features. These non-abutting edges in loose tessellations are also called inconsistent boundaries or slivers; polygons containing at least one inconsistent boundary are called inconsistent polygons or sliver polygons. The existing algorithms to solve topological inconsistencies in sliver polygons suffer from one or more of three major issues, namely determination of tolerances, excessive CPU processing time for large data sets and loss of vertex history. In this article, we introduce a new algorithm that mitigates these three issues. Our algorithm efficiently searches the features with inconsistent polygons in a given spatial data set and logically partitions them among adjacent features. The proposed algorithm employs the constrained Delaunay triangulation technique to generate labelled triangles from which inconsistent polygons with gaps and overlaps are identified using label counts. These inconsistent polygons are then partitioned using the straight skeleton method. Moreover, each of these partitioned gaps or overlaps is distributed among the adjacent features to improve the topological consistency of the spatial data sets. We experimentally verified our algorithm using the real land cadastre data set. The comparison results show that the proposed algorithm is four times faster than the existing algorithm for data sets with 200,000 edges. 相似文献
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R. DUNN A. R. HARRISON J. C. WHITE 《International journal of geographical information science》2013,27(4):385-398
This paper discusses the issues of positional accuracy and measurement error in the context of a large empirical study of landscape change in England and Wales. The epsilon band model of digitizing accuracy is used to make estimates of the levels of positional uncertainty and measurement error that is due to digitizing polygon outlines. The degree of error expected had the same polygons been captured in raster format is then determined. These results prompt a general discussion of the nature of error in spatial databases. 相似文献
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基于GIS和空间句法集成的思路,以江门市历史街区保护更新规划为例,结合实地调研从空间实体的“点、线、面”3个层面分别建立建筑、街巷和地块GIS数据库,利用GIS多因子评价对建筑保护价值进行综合评价,运用空间句法定性定量的分析手段剖析历史街区的街巷路网结构及用地布局,尝试探索建立在量化、实证分析基础上的历史街区保护更新规划的技术方法和流程.研究结果表明:通过量算空间句法参数可以直观解析历史街区空间形态结构和智能性水平,对研究区的规划定位能提供较好的参考;通过空间句法与GIS集成分析对街巷和用地布局的合理性进 相似文献
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沙尘暴是一种危害严重的气象灾害,其形成依赖于大气环流和沙质地表两种不同密度的物理介质的相互作用,风力条件和下垫面的性质是影响沙尘暴强度和危害程度的两个重要因素。减轻沙尘暴危害的有效方法就是改善沙尘暴源地的下垫面状况,但这需要评估下垫面各因子在不同天气、气候背景条件下对沙尘暴发生的影响程度。从下垫面的角度出发,以内蒙古中西部地区为例,利用气象资料和实测数据,应用AHP方法对下垫面定性与定量因子进行综合分析,得出不同地区下垫面因子对沙尘暴发生作用的权重,为从下垫面角度研究沙尘暴危险度奠定基础。 相似文献
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GIS在土地适宜性评价中的应用与展望 总被引：50，自引：3，他引：47
该文阐述了土地适宜性评价的概念和内涵,综述了GIS支持下的各种土地适宜性评价方法及其优缺点。如叠加分析方法、多指标决策模型以及人工智能方法,以研究实例说明如何通过GIS系统引导用户参与分析评价的过程,强调技术层面和群众参与是进行土地适宜性评价不可缺少的两个层面。 相似文献
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Studies of land-use change often require the combination of socioeconomic survey data with spatially continuous maps of land-cover change. One approach is to define maps of land ownership, assuming that all land-use change can be attributed to the owners or managers of each parcel of land. Unfortunately, records of administrative boundaries between towns and villages are commonly unavailable in developing countries and prohibitively costly or time consuming to map for individual projects. However, point locations of the settlements themselves can be obtained easily from existing maps or remotely-sensed imagery. In this paper we compare three methods – circular buffers, unweighted Voronoi polygons (sometimes referred to as Thiessen polygons) and multiplicatively weighted Voronoi polygons – for estimating boundaries between villages in an agricultural landscape in West Africa. The benefits and limitations of each approach are discussed, and their accuracy assessed using 98 independently collected GPS coordinates of village boundaries. We present a novel method for generating and optimising weights for multiplicatively weighted Voronoi polygons using survey data of village sizes from a subset of villages. By using both spatial information and survey data from villages, we show that multiplicatively weighted Voronoi polygons outperform other methods of predicting village boundaries, and increase the correlation coefficient between surveyed village area and mapped areas from 0.18 to 0.68 compared with more commonly used unweighted Voronoi polygons. Our method of weighting Voronoi polygons can be implemented with data and software commonly available to researchers and non-governmental organisations. 相似文献
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Qiming Zhou A-Xing Zhu 《International journal of geographical information science》2013,27(7):1269-1271
Volunteered Geographic Information (VGI) represents a growing source of potentially valuable data for many applications, including land cover map validation. It is still an emerging field and many different approaches can be used to take value from VGI, but also many pros and cons are related to its use. Therefore, since it is timely to get an overview of the subject, the aim of this article is to review the use of VGI as reference data for land cover map validation. The main platforms and types of VGI that are used and that are potentially useful are analysed. Since quality is a fundamental issue in map validation, the quality procedures used by the platforms that collect VGI to increase and control data quality are reviewed and a framework for addressing VGI quality assessment is proposed. A review of cases where VGI was used as an additional data source to assist in map validation is made, as well as cases where only VGI was used, indicating the procedures used to assess VGI quality and fitness for use. A discussion and some conclusions are drawn on best practices, future potential and the challenges of the use of VGI for land cover map validation. 相似文献
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基于多目标遗传算法的土地利用空间结构优化配置 总被引：12，自引：0，他引：12
针对如何将土地利用数量结构落实到具体的地域空间，以实现土地资源的优化配置的土地利用总体规划编制难点，以及常规的叠加法等土地利用配置方法难以根据土地适宜性评价结果，有效地将土地利用数量结构匹配到具体的土地单元问题，该文利用遗传算法的内在并行机制及其全局优化的特性，提出了基于多目标遗传算法的土地利用空间结构优化配置方法。实例分析表明，该方法具有客观性强、灵活性高、操作简便等优点。 相似文献
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Alejandro Velázquez Jean‐François Mas Gerardo Bocco José Luis Palacio‐Prieto 《Singapore journal of tropical geography》2010,31(2):152-162
Land use conversion typically implicates deforestation and fragmentation of primary land cover types, which invariably translates into impoverishment of both natural and cultural capital. Understanding where conversion is taking place crucially underpins sound environmental policy instruments to prevent these enormous social and economic costs. This paper examines 30 years of semi‐detailed (1:250 000) land cover mapping in Mexico. Pre‐existing analogue databases describing land cover patterns in the 1970s and 1990s were reviewed, corrected, reorganized and transformed into a digital format. Current land cover patterns were depicted by conducting updated reinterpretation on Landsat ETM+ imagery. Digital cartographic overlaying was performed and the results were used to construct a spatially explicit land use/land cover change (LULCC) database with an additional accuracy assessment procedure. The value of the results of this analysis is also seen in the light of their direct applications for identifying critical watershed trends, for guiding the allocation of financial funds for sound land use planning and for assessing the effectiveness of established protected areas. This effort highlights the importance of new and more effective geographical approaches to depict, understand and contribute to informed measures to mitigate ongoing negative trends in land cover and climatic changes. 相似文献
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A SOTER-based automatic procedure for qualitative land evaluation is developed. This procedure was created in the automated land evaluation system (ALES). The objective was to design a procedure that allows for a quick separation of potentially suitable from non-suitable SOTER units for the intended land use, indicating constraints to different kinds of land use. Different kinds of land are unequal1y suited to various uses, land eva1uation is the assessment of the suitability of a tract of land for a specified kind of land use. In practice this implicates the comparison (matching) between the requirements of a specified land use and the properties of the land. Land evaluation concepts and definitions are treated in the paper. The ALES is a computer program that allows land evaluators to build their own knowledge-based system with which they can compute the physical and economical suitability of map units in accordance with FAO framework for land evaluation. The ALES program works with so-called decision trees, being hierarchical multiway keys in which the leaves are results (e.g., severity levels of land qualities), and the interior nodes of the tree are decision criteria (e.g., land characteristic values). These trees are traversed by the program to compute an evaluation using actual land data for each map unit. SOTAL is a SOTER-based qualitative model developed in ALES for physical land evaluation in which presently three land utilization types (LUTs) are distinguished, i.e., cultivated banana, coffee and rubber under different input and technological conditions. These LUTs are characterized by 11 landuse requirements and evaluated by matching the land use requirements with the corresponding land qualities. The paper elaborates on the criteria used in SOTAL for land quality assessment and how a final suitability rating is achieved on the basis of the rated land qualities. Results are visualized through G1S-generated maps as products in response to the specific information and data needs of decision and policy makers. 相似文献
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Exploring suitability for tropical crop cultivation in Hainan Island by SOTAL methodology 总被引：6，自引：0，他引：6
1 Introduction Land degradation is a major threat to environmental and agricultural quality of land[1] and is directly related to food security issues. An instrument for decision-makers to plan or stimulate allocation of land to users that can be sustained and are economically viable and socially acceptable. Different kinds of land are unequally suited to various uses. Land evaluation is the assessment of the suitability of a tract of land for a specified kind of use and it provides objective… 相似文献
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以防沙治沙为目标的土地利用方式调整——以内蒙古自治区多伦县为例 总被引：9，自引：3，他引：6
风沙现象的发生与作用力(风力)大小和下垫面特征密切相关,土地利用方式反下垫面的特性,从而影响风沙现象的发生和发展。本文以地处半干旱地区的内蒙古多伦县为例,在充分查明原有每个土地利用地块抗风蚀特性,和生态安全性的基础上,根据下列原则:(1)依照大的地貌类型或地貌区域的差异,进行宏观尺度上土地利用格局配置;(2)不再沙化条件下维持生态安全;和(3)充分考虑目前现实状况,进行以防沙治沙为目标的土地利用方式调整。调整结果反映在两县市的1∶250000土地利用图上。另外,对多伦县的土地利用格局也作了初步探讨。 相似文献
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基于GIS技术的泥石流风险评价研究 总被引：49，自引：15，他引：49
为了满足对自然灾害预测不断增长的紧迫要求，泥石流风险评价成为帮助决策过程重要的基础工具之一。即使泥石流风险性各组分的评价很困难，但地理信息系统可辅助提出这种风险性制图的有关方法。我们以云南省为研究区，选取6个成因因子参与泥石流危险度敏感性分析，通过将研究区易损性评价图与危险性评价图叠加分析，编制出云南省泥石流风险评价图。该图描述了在现有自然条件和人类活动下的泥石流风险敏感区。研究成果为全面反映灾情，确定减灾目标，优化防御措施，进行减灾决策提供了重要依据。 相似文献
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PAUL V. BOLSTAD PAUL GESSLER THOMAS M. LILLESAND 《International journal of geographical information science》2013,27(4):399-412
Digital map coordinates represent the locations of real world entities. As such, differences can exist between the ‘tru’ and digital database coordinates of those entities. This paper reports on a statistical characterization of positional error in manually-digitized and map-registered point data, the relative contribution of point type and operator to digitization error, and the effects of map media type on the positional uncertainty associated with registration. Manually-digitized point data were collected by four operators from mylar and paper maps. Point locations for a number of different feature types were sampled from United States Geological Survey (USGS) 1:24 000 scale maps. Linear models were used to estimate the variance components due to among-operator, map media, point type and registration effects. The statistical distribution of signed distance deviations for manually-digitized data was leptokurtic relative to a random normal variate. Unsigned deviations averaged 0-054 mm. Squared distance deviations were not different from a Chi-square random variate. Variance components indicate that among-operator differences in positional uncertainty were large and statistically significant, while differences among point type were small and non-significant. Signed distance deviations associated with a first-order afhne followed a normal distribution. Unsigned distance deviations associated with a first-order affinc transformation averaged 0068mm, and squared distance deviations were distributed as a Chi-square. Differences in transformation accuracy were not related to type of map media. 相似文献
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Megan Mills-Novoa Philippo Pszczólkowski Francisco Meza 《The Professional geographer》2016,68(4):561-573
This study uses the case of the Maipo Valley in Chile to examine how climate change will affect viticultural suitability. Using a geographic information system analysis of topographic, soil, land use, and climate data, a baseline assessment of viticultural suitability in the Maipo Valley was performed. The impact of climate change on viticultural suitability was modeled by overlaying downscaled global circulation model temperature data for two emission scenarios. The findings of this study suggest that the capacity of vineyard managers in the Maipo Valley to cultivate high-quality traditional grape varietals from cooler grape maturity classes might be limited in the future. 相似文献
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Y.H. Ran X. Li L. Lu Z.Y. Li 《International journal of geographical information science》2013,27(1):169-191
Land cover type is a crucial parameter that is required for various land surface models that simulate water and carbon cycles, ecosystem dynamics, and climate change. Many land use/land cover maps used in recent years have been derived from field investigations and remote-sensing observations. However, no land cover map that is derived from a single source (such as satellite observation) properly meets the needs of land surface simulation in China. This article presents a decision-fuse method to produce a higher-accuracy land cover map by combining multi-source local data based on the Dempster–Shafer (D–S) evidence theory. A practical evidence generation scheme was used to integrate multi-source land cover classification information. The basic probability values of the input data were obtained from literature reviews and expert knowledge. A Multi-source Integrated Chinese Land Cover (MICLCover) map was generated by combining multi-source land cover/land use classification maps including a 1:1,000,000 vegetation map, a 1:100,000 land use map for the year 2000, a 1:1,000,000 swamp-wetland map, a glacier map, and a Moderate-Resolution Imaging Spectroradiometer land cover map for China in 2001 (MODIS2001). The merit of this new map is that it uses a common classification system (the International Geosphere-Biosphere Programme (IGBP) land cover classification system), and it has a unified 1 km resolution. The accuracy of the new map was validated by a hybrid procedure. The validation results show great improvement in accuracy for the MICLCover map. The local-scale visual comparison validations for three regions show that the MICLCover map provides more spatial details on land cover at the local scale compared with other popular land cover products. The improvement in accuracy is true for all classes but particularly for cropland, urban, glacier, wetland, and water body classes. Validation by comparison with the China Forestry Scientific Data Center (CFSDC)–Forest Inventory Data (FID) data shows that overall forest accuracies in five provinces increased to between 42.19% and 88.65% for our MICLCover map, while those of the MODIS2001 map increased between 27.77% and 77.89%. The validation all over China shows that the overall accuracy of the MICLCover map is 71%, which is higher than the accuracies of other land cover maps. This map therefore can be used as an important input for land surface models of China. It has the potential to improve the modeling accuracy of land surface processes as well as to support other aspects of scientific land surface investigations in China. 相似文献
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Christin Loran Susette Haegi Christian Ginzler 《International journal of geographical information science》2018,32(11):2123-2139
Topographic maps are powerful tools for the purpose of identifying land use and cover change (LUCC) as they are among the most reliable representations of past landscapes for the time prior to the existence of aerial photography. In light of the increased availability of historical maps, we argue that there is a need for a standardized process to assess map comparability in a systematic way in order to avoid, or at least minimize, the detection of spurious landscape changes due to incompatible map series. A full understanding of map quality, background and error distributions is fundamental to attain reliable LUCC results. The conceptual framework presented in this study considers the context, distortion and cartographic generalization of topographic maps. Furthermore, it includes an approach to homogenize the level of generalization of landscape elements (e.g. forests) from maps with different scales. To demonstrate its application, we assessed the comparability of seven topographic maps from Canton Zurich covering a time span of 336 years (1664–2000). Overall, for the maps of Canton Zurich, a wall-to-wall comparison of forest cover based on the topographic maps presented here can be problematic for the oldest map from 1664. Based on the results, a wall-to-wall comparison with the later maps is not recommended, due to its substantial distortion. Yet, after re-generalization of natural landscape elements, such as forests, a comparison based on landscape indices is possible, even for the oldest map. Furthermore, our results demonstrate that maps from the mid-19th century onward possess an acceptable level of accuracy. This framework can be applied to a wide range of maps at regional, national, or global levels, providing the opportunity to look at land cover history over multiple centuries. 相似文献
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土地利用调查中图斑平均坡度的获取方法 总被引：3，自引：0，他引：3
图斑的平均坡度是新一轮土地利用更新调查中确定土地利用是否合理的重要参 数,但常用的图斑平均坡度获取方法均存在不同程度的不足.探讨图斑平均坡度的算法原 理,以浙江省某县的地形图数据与土地利用更新调查数据为基准数据,提出由TIN内插成DEM ,在此基础上利用ArcGIS得出各土地利用图斑的平均坡度.经验证,该方法的相对误差在4% 以内,平均相对误差为2.2%,精度符合应用要求. 相似文献