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21.
ZHANG Li GONG Jianya ZHU QingZHANG Li Ph.D.Candidate National Laboratory for Information Engineering in Surveying Mapping Remote Sensing WTUSM Luoyu Road Wuhan China 《地球空间信息科学学报》2000,3(3):47-51
1 IntroductionNeedlesstosay ,itisveryimportantformostGISuserstoacquireandintegratethegeospatialinfor mationfromvariousdistricts.However ,thecurrentsituationofgeospatialinformationproductionanddisseminationintheworldisstillunsatisfactory .Ononehand ,usersd… 相似文献
22.
针对人们对地理空间数据迫切需求,介绍了多源地理空间矢量数据产生的管理与技术原因及其5种表现形式,提出了多源地理空间矢量数据集成与融合的概念及其相互关系。论述了地理数据模型的融合、地理要素语义的融合和地理数据投影和坐标系的统一是多源地理空间矢量数据集成与融合基本理论与方法。给出了实现多源数据集成的数据格式转换、数据互操作和直接数据访问方法。最后,讨论了地理要素几何位置的融合,以及通过地理要素语义融合消除地理要素数据描述和属性差异的矢量数据融合方法。 相似文献
23.
地理信息服务质量(QoGIS):概念和研究框架 总被引:2,自引:0,他引:2
在探讨地理数据特点的基础上,提出了地理信息服务质量(QoGIS)的概念和研究框架,设计了一个体现地理信息服务质量的原型系统架构。 相似文献
24.
Iain McDonald 《Geostandards and Geoanalytical Research》1998,22(1):85-91
Platinum-group element (PGE) concentrations and the distribution of the metals in rocks serve as important tracers of mantle processes, as well as extraterrestrial input into crustal environments, but common standards regarding the gathering and presentation of PGE data have never been formalized. Effective modelling assumes that concentration data are within acceptable levels of precision, yet the practices used in some studies to determine precision do not adequately assess precision and, as a result, the uncertainties on PGE concentrations and PGE ratios are sometimes consistently underestimated. This article argues that replicate analyses of unknowns must be adopted more widely in order to overcome this problem. Related to the issue of uncertainties on PGE concentrations, is the issue of uncertainty associated with normalisation. Arguments have recently been put forward as to the significance of small positive or negative anomalies on chondrite nor-malized plots. At least four CI chondrite PGE datasets (of varying age and quality) are currently used for normalisation and significantly different patterns can be derived simply by using one dataset rather than another. This article is intended to open a debate within the PGE research community by asking whether more consistency needs to be applied in PGE analysis and in the subsequent interpretation of data. A rigorous assessment of the real uncertainties on PGE concentrations and the adoption of a standard CI chondrite PGE dataset, in order to eliminate bias from normalisation, are suggested to be central to this. 相似文献
25.
Analysis of ocean fronts' uncertainties indicates that they result from indiseemibility of their spatial position and fuzzi-ness of their intensity. In view of this, a flow hierarchy for uncertainty representation of ocean fronts is proposed on the basis of fuzzy-rough set theory. Firstly, raster scanning and blurring are carried out on an ocean front, and the upper and lower approximate sets, the indiscernible relation in fuzzy-rough theories and related operators in fuzzy set theories are adopted to represent its uncer-tainties, then they are classified into three sets: with members one hundred pereent belonging to the ocean front, belonging to the ocean front's edge and definitely not belonging to the ocean front. Finally, the approximate precision and roughness degree are util-ized to evaluate the ocean front's degree of uncertainties and the precision of the representation. It has been proven that the method is not only capable of representing ocean fronts' uncertainties, but also provides a new theory and method for uncertainty representation of other oceanic phenomena. 相似文献
26.
介绍了基于Geodatabase的空间数据牢设计方法,设计了城市基础地理空间数据库,并实现了城市基础地理空间数据的整合与共享。 相似文献
27.
地理信息数据质量的概念、评价和表述——地理信息数据质量控制国家标准核心内容浅析 总被引:2,自引:1,他引:1
介绍已经报批的国家标准<地理信息质量原则>和<地理信息质量评价过程>所确定的地理信息数据质量元素、子元素及其描述符,数据质量评价的方法、内容和要求,以及数据质量评价结果的表达方法,并就我国这一领域存在的问题和相关标准及今后的发展简单地进行了分析. 相似文献
28.
This paper develops an adaptive fuzzy controller for the dynamic positioning (DP) system of vessels with unknown dynamic model parameters and unknown time-varying environmental disturbances. The controller is designed by combining the adaptive fuzzy system with the vectorial backstepping method. An adaptive fuzzy system is employed to approximate the uncertain term induced by unknown dynamic model parameters and unknown time-varying environmental disturbances. It is theoretically proved that the proposed adaptive fuzzy DP controller can make the vessel be maintained at the desired values of its position and heading with arbitrary accuracy, while guaranteeing the uniform ultimate boundedness of all signals in the closed-loop DP control system of vessels. Simulation studies with comparisons on a supply vessel are carried out, and the results illustrate the effectiveness of the proposed control scheme. 相似文献
29.
Isabel Pôças João Gonçalves Bruno Marcos Joaquim Alonso Pedro Castro João P. Honrado 《International journal of geographical information science》2014,28(11):2356-2371
This article proposes and illustrates a practical methodological framework to evaluate the fitness for use of spatial data sets for environmental and ecological applications, focusing on user requirements for specified application contexts. The methodology is based on the use of metadata to analyze similarity between the data characteristics and the user’s needs or expectations for several quality indicators. Additionally, the concept of ‘critical factors’ is introduced in this framework, allowing users to define which quality indicators have greater importance given their own requirements or expectations and the specified application contexts. The proposed methodology further allows integrating and interconnecting the spatial data quality (SDQ) evaluation methodology with metadata geoportals in WebGIS platforms, facilitating its operation by users from non-spatial disciplines and with often limited expertise on this subject. Examples of the evaluation of fitness for use for specific application contexts within the project BIO_SOS (‘Biodiversity Multi-SOurce Monitoring System: From Space To Species’ FP7 project) are presented. By providing a prompt and straightforward evaluation tool, the proposed methodology can encourage the implementation of SDQ evaluation routines in ecological assessment and monitoring programs, promoting a more adequate use of geospatial data and ultimately contributing to well-supported policy and management decisions. 相似文献
30.
Seung Man An Ho-Young Lee Byungsoo Kim Chae-Yeon Yi Jeong-Hee Eum 《International journal of geographical information science》2014,28(12):2511-2532
A major obstacle of the interdisciplinary communications for decision-making is that each participant prefers the solution from their own area because current collaboration systems cannot effectively mediate among many alternatives. If a visual collaboration system could display multiple alternatives in a single visual presentation, users would be able to compare alternatives with only a few variables, where all other parameters are fixed, at least from a visual perspective. In this study, we developed a visualization tool to support a microscale air quality (MSAQ) management group, the members of which often need to compare the effects of many alternative control methods. The main achievements of this study are: (1) three-dimensional (3D) visualization of the MSAQ using a 3D city model and (2) development of a geospatial spreadsheet (GS) to facilitate visual comparisons, thereby improving decision-making by making it easy to compare differences based on realistic visual display items. A questionnaire-based survey showed that use of the GS could generate a shared perspective and provide a spatiotemporal context for the participants, thereby making it easy to compare, mediate and reach decisions when confronted with many alternatives. 相似文献