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91.
针对当前数字区域工程建设普遍存在的一些问题,提出“数字区域”应用基础设施的概念,对其研究背景、参考模型和面向信息共享的公共应用服务平台进行了论述。数字区域应用基础设施是在区域网络基础设施和数据基础设施上层的基础设施,它为电子政务、电子商务、数字城市等各种数字区域信息化应用工程提供基础性的应用服务支撑,由专业信息服务机构、管理办法、标准规范、关键技术和公共应用服务平台构成。信息服务机构是数字区域应用基础设施的主体,是有效联系信息需求方和信息拥有方的桥梁;公共应用服务平台是数字区域应用基础设施的核心,为区域信息共享和交换提供了统一的构架和解决方案。其中,元数据管理和目录服务平台为信息的发布和查询提供了“一站式”入口;信息共享与协作服务平台实现了分布式数据库的信息共享和交换;地理空间信息网络服务平台实现了地理空间信息的集中式共享。最后,总结了“数字福建”应用基础设施建设的成果,对“十一五”“数字福建”工程的需求和发展作了展望。  相似文献   
92.
INTRODUCTIONInternet,aglobalnetworkofcomputersconnectedthroughcommunicationdevices,providesGISusersanaccesstoremotegeographicdata .Theweb basedGIS ,akindofinternet basedGIStoolfortheaccesstoremotegeographicinformation ,ispro posedinthispaper.Nowadays ,thewe…  相似文献   
93.
西北地下水资源数据库包括地下水资源属性数据库和地下水资源空间数据库,属性数据库采用AC-CESS97存储格式,空间数据库采用ARCVIEW3.1存储格式,文中介绍了西北地下水资源数据库的基本内容,组织结构及其元数据,阐述了其在网上发布的动态网页设计思路及基于WEB GIS的数据浏览,查询的设计思路。  相似文献   
94.
The food sources of aquacultured Apostichopus japonicus and the trophic levels of organisms in a sea cucumber(A. japonicus) and prawn(Penaeus japonica) polyculture system in a saltwater pond in Zhuanghe, Liaoning Province were examined using carbon and nitrogen stable isotopes. Across organisms, δ13C ranged from(–25.47±0.20)‰ to(–16.48±0.17)‰(mean±SD), and δ15N ranged from(4.23±0.49)‰ to(12.44±0.09)‰. The δ13C and δ15N contents of A. japonicus, P. japonica and Fenneropenaeus chinensis were comparatively higher than those of other organisms. Values of δ13C and δ15N revealed that P. japonica, Hemigrapsus sanguineus and Neomysis japonica comprised the largest component of the diet of A. japonicus. The mean trophic level of the organisms in this saltwater pond polyculture system was(2.75±0.08). P. japonica, A. japonicus, F. chinensis,Synechogobius hasta and Neomysis japonica were in the 3rd trophic level(2–3); jellyfish, H. sanguineus and zooplankton were in the 2nd trophic level(1–2); and Enteromorpha prolifera, benthic microalgae, periphyton and suspended matter primarily consisting of phytoplankton, bacteria and humus were in the primary trophic level(0–1).  相似文献   
95.
Extreme flood events often have adverse effects for people living near or within areas at risk. Reactivating morphological river floodplains for flood retention measures can substantially reduce flood wave peaks and the negative flooding consequences. This article accordingly focuses on a methodology for identifying suitable locations for such measures by spatial multicriteria evaluation (MCE). Compromise programming (CP) and the analytic hierarchy process (AHP) are core methodological components. Furthermore, this methodology is based on impact analysis and draws on expert knowledge. This article also deals with software tools that support the operationalization of methodological components. Data harmonization algorithms are implemented as geoprocessing tools. Both CP and AHP are designed as software providing graphical user interfaces (GUIs). While an extension integrates CP into a geoinformation system, AHP is realized as a web application enabling participation of expert practitioners. The methodological components are operationalized through an example on the floodplains of the German river Elbe.  相似文献   
96.
ABSTRACT

The need and critical importance of global land cover and change information has been well recognized. Although rich collection of such information has been made available, the lack of necessary information services to support its easy access, analysis and validation makes it difficult to find, evaluate, select and reuse them through well-designed workflows. Aiming at promoting the development of the needed global land cover information services, this paper presents a conceptual framework for developing a Collaborative Global Land Cover Information Service (CoGland), followed by discussions on its implementation strategies. The framework supports connected and shared land cover and change web services around the world to address resource sharing, community service and cross-board collaboration needs. CoGland can benefit several recent international initiatives such as Future Earth, and many societal benefit areas. The paper further proposes that CoGland be developed within the framework of the Group on Earth Observations with the support of a number of key organizations such as the United Nations Expert Committee on Global Geospatial Information Management, the International Society for Photogrammetry and Remote Sensing, and International Society of Digital Earth. It is hoped that this paper can serve as a starting point for further discussions on CoGland developments.  相似文献   
97.
魏勇  胡丹露  李响  王丰 《测绘工程》2016,25(2):28-32
地名数据是一种重要的地理信息资源,目前我国的地名数据库建设多局限于国内地名,缺少国外数据。传统地名数据的检索多为关键字查询,查询效率低且无法用于复杂地名查询。文中提出一种基于开源地名数据库GeoNames和开源搜索引擎Solr的地名数据全文检索方法,通过分析GeoNames的数据类型和结构,构建MySQL地名数据库,并利用Solr建立地名索引,提供基于Web服务的地名数据全文检索。实验表明,基于Solr的地名数据全文检索能够显著提高地名数据检索效率,对于复杂地名查询,也能进行有效地检索。  相似文献   
98.
Because food web regimes control the biomass of primary producers (e.g., plants or algae), intermediate consumers (e.g., invertebrates), and large top predators (tuna, killer whales), they are of societal as well as academic interest. Some controls over food web regimes may be internal, but many are mediated by conditions or fluxes over large spatial scales. To understand locally observed changes in food webs, we must learn more about how environmental gradients and boundaries affect the fluxes of energy, materials, or organisms through landscapes or seascapes that influence local species interactions. Marine biologists and oceanographers have overcome formidable challenges of fieldwork on the high seas to make remarkable progress towards this goal. In river drainage networks, we have opportunities to address similar questions at smaller spatial scales, in ecosystems with clear physical structure and organization. Despite these advantages, we still have much to learn about linkages between fluxes from watershed landscapes and local food webs in river networks. Longitudinal (downstream) gradients in productivity, disturbance regimes, and habitat structure exert strong effects on the organisms and energy sources of river food webs, but their effects on species interactions are just beginning to be explored. In fluid ecosystems with less obvious physical structure, like the open ocean, discerning features that control the movement of organisms and affect food web dynamics is even more challenging. In both habitats, new sensing, tracing and mapping technologies have revealed how landscape or seascape features (e.g., watershed divides, ocean fronts or circulation cells) channel, contain or concentrate organisms, energy and materials. Field experiments and direct in situ observations of basic natural history, however, remain as vital as ever in interpreting the responses of biota to these features. We need field data that quantify the many spatial and temporal scales of functional relationships that link environments, fluxes and food web interactions to understand how they will respond to intensifying anthropogenic forcing over the coming decades.  相似文献   
99.
Seasonal changes in nano/micro-zooplankton grazing on pico-, nano- and micro-size phytoplankton and heterotrophic nano-flagellates (HNF) feeding on heterotrophic bacteria were quantified by the dilution technique in the surface layer off Cape Esan, southwestern Hokkaido, Japan. Pico- and nano-size phytoplankton were major components throughout the year except in spring when a diatom bloom was observed. Although there was little seasonal variation in bacteria and HNF biomass throughout the year, the micro-zooplankton biomass varied appreciably with a peak in spring. Nano/micro-zooplankton grazing or feeding on pico-size chl-a and bacteria were well balanced throughout the year. However, nano-size and micro-size chl-a growth were much greater than grazing in summer. Nano/micro-zooplankton ingestion of phytoplankton was greater than their ingestion of bacteria almost throughout the year, which suggests phytoplankton are more important as food sources of nano/micro-zooplankton in microbial food webs off Cape Esan than bacteria off Cape Esan. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
100.
Food web interactions and the response of Pacific salmon to physical processes in the North Pacific Ocean over interannual and interdecadal timescales are explored using naturally occurring stable isotope ratios of carbon (13C/12C) and nitrogen (15N/14N). Stable isotope analyses of five species of sexually mature North Pacific salmon from Alaska (Oncorhynchus spp.) cluster into three groups: chinook salmon (O. tshawytscha) have the highest values, followed by coho (O. kisutch), with chum (O. keta), sockeye (O. nerka), and pink (O. gorbuscha) together having the lowest values. Although detailed isotopic data on salmon prey are lacking, there are limited data on relevant prey items from areas in which they are found in high abundance. These data suggest that the characteristics of the sockeye, pink and chum we have analyzed are compatible with their diets including open ocean squid and zooplankton, which are in general agreement with stomach content analyses. Isotope relationships between muscle and scale show consistent relationships for both δ13C (R2=0.98) and δ15N (R2=0.90). Thus, scales, which have been routinely archived for many systems, can be used for retrospective analyses. Archived sockeye salmon scales spanning 1966–1999 from Red Lake, Kodiak Island, Alaska were analyzed for their stable isotope ratios of carbon and nitrogen. The δ15N record displays a decreasing trend of ˜3‰ from 1969–1982 and an increasing trend of ˜3‰ from 1982–1992, while the variations in δ13C are relatively minor. These trends may result from factors such as shifts in trophic level of feeding and/or feeding location, or may originate at the base of the food web via changes in processes such as nutrient cycling or primary productivity. Detailed studies on prey isotopic variability and its controls are needed to distinguish between these factors, and thus to improve the use of stable isotope analysis as a tool to learn more about present and past ecosystem change in the North Pacific and its relation to climatic change.  相似文献   
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