排序方式： 共有24条查询结果，搜索用时 15 毫秒
11.
Johannes F. Kruiger Vedran Kasalica Rogier Meerlo Anna‐Lena Lamprecht Enkhbold Nyamsuren Simon Scheider 《Transactions in GIS》2021,25(1):424-449
Loose programming enables analysts to program with concepts instead of procedural code. Data transformations are left underspecified, leaving out procedural details and exploiting knowledge about the applicability of functions to data types. To synthesize workflows of high quality for a geo‐analytical task, the semantic type system needs to reflect knowledge of geographic information systems (GIS) at a level that is deep enough to capture geo‐analytical concepts and intentions, yet shallow enough to generalize over GIS implementations. Recently, core concepts of spatial information and related geo‐analytical concepts were proposed as a way to add the required abstraction level to current geodata models. The core concept data types (CCD) ontology is a semantic type system that can be used to constrain GIS functions for workflow synthesis. However, to date, it is unknown what gain in precision and workflow quality can be expected. In this article we synthesize workflows by annotating GIS tools with these types, specifying a range of common analytical tasks taken from an urban livability scenario. We measure the quality of automatically synthesized workflows against a benchmark generated from common data types. Results show that CCD concepts significantly improve the precision of workflow synthesis. 相似文献
12.
韦伯型设施区位的可计算模型及其应用 总被引：4，自引：0，他引：4
设施布局是城市规划中的热点问题,其中具有代表性的韦伯型设施区位应用广泛,能够于离散的空间点区位中配置设施的最佳位置,可解决诸多类型设施的选址问题。以多设施重心模型、最大福利模型和p-中心模型为例,从地计算的角度出发研究其模型及可计算方法。运用可视化开发工具Delphi 7.0作为开发平台,使用建立在OCX技术基础上的专业GIS控件MapObjects进行集成二次开发,建立设施区位分析系统,实现模型的计算及地理分析功能,并以上海市松江区新桥镇社会事业发展规划为例,运用该系统解决其社会事业发展对应设施选址问题。结果表明具有合理性,能够作为设施规划布局的辅助决策依据。 相似文献
13.
基于细胞自动机与多主体系统理论的城市模拟原型模型 总被引：5，自引：5，他引：0
文章从城市地理学模拟模型研究发展相对滞后的现实出发,分析了传统城市模型模拟存在的问题与不足,讨论了计算机科学、复杂性研究、地理信息科学与技术、新发展的地学计算方法等作为计算城市模型发展基础的可行性,提出了一个基于细胞自动机与多主体系统理论与方法、包容了多尺度(宏观、中观、微观)层次的综合可计算城市模拟原型模型框架,对以邻里社区为基础的居住区位微观模拟模型作了概念上的讨论,分析了地学计算方法在城市模拟模型研究中的发展前沿。 相似文献
14.
UCGIS地理信息科学与技术知识体系及对我国GIS研究的启示 总被引：1，自引：1，他引：0
为推进我国地理信息科学与技术发展,借鉴UCGIS于2006年提出的地理信息科学与技术知识体系(Geographic Information Science and Technology Body of Knowledge),分析其对我国GIS领域研究的若干启示,包括构建科学合理的地理信息科学与技术学科体系、加强地理空间认知与概念建模的研究、多学科交叉推进地理计算理论与应用研究、推进地理信息科学与技术的相关软科学研究。 相似文献
15.
Laure Charleux 《International journal of geographical information science》2013,27(7):1125-1143
The time-geographic distinction between fixed and flexible activities is widely acknowledged to be a somewhat arbitrary dichotomy but is still the current modus operandi for time-geographic calculations. This paper proposes a modification of the classic time-geographic framework to support temporal flexibility in ‘fixed’ activities. This modification is crucial for time-geographic calculations on public transit networks with a low frequency of service, which would otherwise return unstable results. 相似文献
16.
P. Brindley J. Goulding M. L. Wilson 《International journal of geographical information science》2018,32(3):498-523
Neighbourhoods have been described as ‘the building blocks of public services society’. Their subjective nature, however, and the resulting difficulties in collecting data, means that in many countries there are no officially defined neighbourhoods either in terms of names or boundaries. This has implications not only for policy but also business and social decisions as a whole. With the absence of neighbourhood boundaries many studies resort to using standard administrative units as proxies. Such administrative geographies, however, often have a poor fit with those perceived by residents. Our approach detects these important social boundaries by automatically mining the Web en masse for passively declared neighbourhood data within postal addresses. Focusing on the United Kingdom (UK), this research demonstrates the feasibility of automated extraction of urban neighbourhood names and their subsequent mapping as vague entities. Importantly, and unlike previous work, our process does not require any neighbourhood names to be established a priori. 相似文献
17.
《International Journal of Digital Earth》2013,6(2):157-186
Abstract A significant Geographic Information Science (GIS) issue is closely related to spatial autocorrelation, a burning question in the phase of information extraction from the statistical analysis of georeferenced data. At present, spatial autocorrelation presents two types of measures: continuous and discrete. Is it possible to use Moran's I and the Moran scatterplot with continuous data? Is it possible to use the same methodology with discrete data? A particular and cumbersome problem is the choice of the spatial-neighborhood matrix (W) for points data. This paper addresses these issues by introducing the concept of covariogram contiguity, where each weight is based on the variogram model for that particular dataset: (1) the variogram, whose range equals the distance with the highest Moran I value, defines the weights for points separated by less than the estimated range and (2) weights equal zero for points widely separated from the variogram range considered. After the W matrix is computed, the Moran location scatterplot is created in an iterative process. In accordance with various lag distances, Moran's I is presented as a good search factor for the optimal neighborhood area. Uncertainty/transition regions are also emphasized. At the same time, a new Exploratory Spatial Data Analysis (ESDA) tool is developed, the Moran variance scatterplot, since the conventional Moran scatterplot is not sensitive to neighbor variance. This computer-mapping framework allows the study of spatial patterns, outliers, changeover areas, and trends in an ESDA process. All these tools were implemented in a free web e-Learning program for quantitative geographers called SAKWeb© (or, in the near future, myGeooffice.org). 相似文献
18.
《International Journal of Digital Earth》2013,6(5):383-402
Geospatial Semantic Web promises better retrieval geospatial information for Digital Earth systems by explicitly representing the semantics of data through ontologies. It also promotes sharing and reuse of geospatial data by encoding it in Semantic Web languages, such as RDF, to form geospatial knowledge base. For many applications, rapid retrieval of spatial data from the knowledge base is critical. However, spatial data retrieval using the standard Semantic Web query language – Geo-SPARQL – can be very inefficient because the data in the knowledge base are no longer indexed to support efficient spatial queries. While recent research has been devoted to improving query performance on general knowledge base, it is still challenging to support efficient query of the spatial data with complex topological relationships. This research introduces a query strategy to improve the query performance of geospatial knowledge base by creating spatial indexing on-the-fly to prune the search space for spatial queries and by parallelizing the spatial join computations within the queries. We focus on improving the performance of Geo-SPARQL queries on knowledge bases encoded in RDF. Our initial experiments show that the proposed strategy can greatly reduce the runtime costs of Geo-SPARQL query through on-the-fly spatial indexing and parallel execution. 相似文献
19.
Characterization of neighborhood sensitivity of an irregular cellular automata model of urban growth
Khila R. Dahal T. Edwin Chow 《International journal of geographical information science》2013,27(3):475-497
The neighborhood definition, which determines the influence on a cell from its nearby cells within a localized region, plays a critical role in the performance of a cellular automaton (CA) model. Raster CA models use a cellular grid to represent geographic space, and are sensitive to the cell size and neighborhood configuration. However, the sensitivity of vector-based CAs, an alternative to the raster-based counterpart, to neighborhood type and size remains uninvestigated. The present article reports the results of a detailed sensitivity analysis of an irregular CA model of urban land use dynamics. The model uses parcel data at the cadastral scale to represent geographic space, and was implemented to simulate urban growth in Central Texas, USA. Thirty neighborhood configurations defined by types and sizes were considered in order to examine the variability in the model outcome. Results from accuracy assessments and landscape metrics confirmed the model’s sensitivity to neighborhood configurations. Furthermore, the centroid intercepted neighborhood with a buffer of 120 m produced the most accurate simulation result. This neighborhood produced scattered development while the centroid extent-wide neighborhood resulted in a clustered development predominantly near the city center. 相似文献
20.
Donna J. Peuquet Anthony C. Robinson Samuel Stehle Franklin A. Hardisty Wei Luo 《International journal of geographical information science》2013,27(9):1588-1611
Pattern analysis techniques currently common within geography tend to focus either on characterizing patterns of spatial and/or temporal recurrence of a single event type (e.g., incidence of flu cases) or on comparing sequences of a limited number of event types where relationships between events are already represented in the data (e.g., movement patterns). The availability of large amounts of multivariate spatiotemporal data, however, requires new methods for pattern analysis. Here, we present a technique for finding associations among many different event types where the associations among these varying event types are not explicitly represented in the data or known in advance. This pattern discovery method, known as T-pattern analysis, was first developed within the field of psychology for the purpose of finding patterns in personal interactions. We have adapted and extended the T-pattern method to take the unique characteristics of geographic data into account and implemented it within a geovisualization toolkit for an integrated computational-geovisual environment we call STempo. To demonstrate how T-pattern analysis can be employed in geographic research for discovering patterns in complex spatiotemporal data, we describe a case study featuring events from news reports about Yemen during the Arab Spring of 2011–2012. Using supplementary data from the Global Database of Events, Language, and Tone, we briefly summarize and reference a separate validation study, then evaluate the scalability of the T-pattern approach. We conclude with ideas for further extensions of the T-pattern technique to increase its utility for spatiotemporal analysis. 相似文献