历史时期渭河中下游平原水旱灾害

1IntroductionFor long historical development course, we know that the changes of natural environment and resources have interactive effect with the construction, development and decline of the cities. Internationally, there were some relevant researches, …     

Response of vegetation restoration to climate change and human activities in Shaanxi-Gansu- Ningxia Region

The “Grain for Green Project” initiated by the governments since 1999 were the dominant contributors to the vegetation restoration in the agro-pastoral transitional zone of northern China. Climate change and human activities are responsible for the improvement and degradation to a certain degree. In order to monitor the vegetation variations and clarify the causes of rehabilitation in the Shaanxi-Gansu-Ningxia Region, this paper, based on the MODIS-NDVI and climate data during the period of 2000-2009, analyzes the main characteristics, spatial-temporal distribution and reasons of vegetation restoration, using methods of linear regression, the Hurst Exponent, standard deviation and other methods. Results are shown as follows. (1) From 2000 to 2009, the NDVI of the study area was improved progressively, with a linear tendency being 0.032/10a, faster than the growth of the Three-North Shelter Forest Program (0.007/10a) from 1982 to 2006. (2) The vegetation restoration is characterized by two fast-growing periods, with an “S-shaped” increasing curve. (3) The largest proportion of the contribution to vegetation restoration was observed in the slightly improved area, followed by the moderate and the significantly improved area; the degraded area is distributed sporadically over southern part of Ningxia Hui Autonomous Region as well as eastern Dingbian of Shaanxi province, Huanxian and Zhengyuan of Gansu province. (4) Climate change and human activities are two driving forces in vegetation restoration; moreover anthropogenic factors such as “Grain for Green Project” were the main causes leading to an increasing trend of NDVI on local scale. However, its influencing mechanism remains to be further investigated. (5) The Hurst Exponent of NDVI time series shows that the vegetation restoration was sustainable. It is expected that improvement in vegetation cover will expand to the most parts of the region.     

石河子垦区蟠桃越冬不同覆盖方式的安全性对比试验

通过在石河子垦区2个年度开展的草帘膜覆盖法、纸箱塑料膜覆盖法、玉米杆覆土覆盖法等保护蟠桃越冬的对比试验,分析不同覆盖方法覆盖物内外温、湿度资料与冻害发生状况,初步得到：覆盖后蟠桃树周边所处的极端最低温度要高于-22℃~-24℃,相对湿度保持在70~90%才能较好地保证蟠桃树安全越冬。玉米杆覆土覆盖法是三种方法中保证蟠桃越冬效果最好,但又是花费最高的方法。     

分布式空间数据标记语言的研究与实现

提出了一种基于XML的分布式空间数据建模及可视化表达的描述语言——分布式空间数据标记语言(DSDML);讨论了DSDML的应用框架、功能、语法规则,基于SAX模型实现了DSDML的解析器,并在Google Earth和GeoGlobe上进行了实验,实现了DSDML与Google Earth或GeoGlobe的无缝集成。     

GIS符号的跨平台通用技术研究

提出了一种利用虚拟机技术实现不同GIS平台之间符号共享的方法。整个符号系统由符号虚拟机、符号虚拟机挂接插件和符号设计工具3部分组成。符号虚拟机是专门执行符号化工作的机器,独立于具体的GIS平台,负责处理GIS平台无关的符号化功能;符号虚拟机挂接插件用于实现GIS平台与符号虚拟机之间的挂接,使GIS平台能够调用符号虚拟机的功能进行符号化;符号设计工具则用于生产符号,生产符号时只面向符号虚拟机,不面向具体的GIS平台,这样符号就可以在所有挂接了符号虚拟机的GIS平台上通用并能达到一致的表现效果。     

一种VGI矢量数据增量变化发现的多层次蔓延匹配算法

目的 矢量要素的匹配是发现地物要素变化的重要方法之一,高精度的匹配结果有助于更快地发现变化地物,进行更新。VGI矢量数据具有几何和语义信息丰富的特点,但使用传统的矢量要素匹配算法难以发挥VGI矢量数据的优势。以城市 VGI道路数据为研究内容,提出基于多层次蔓延的矢量要素匹配算法,将 VGI数据和专业测绘数据进行匹配对比,从而实现道路变化增量信息的快速识别。     

基于JSP/JavaBean的Web GIS实现技术

研究了如何利用JSP/JavaBean技术更好地实现WebGIS系统,提出了基于JSP/JavaBean的Web GIS实现模型,并以应用实例加以说明。     

面向网络的海量影像空间数据在线分发技术

阐述了基于J2EE的海量空间数据在线分发系统原理和关键技术,给出了海量影像空间数据在线浏览发布的实例。     

论空间信息与移动通信的集成应用

分析了空间信息技术与移动通信技术集成的必要性和可行性,讨论了技术集成所面临的关键技术,提出了空间信息与移动通信集成的体系结构,归纳总结了其应用领域和市场前景。     

Web GIS组件方法研究

在分析Web GIS二次开发需求的基础上,提出了基于JavaBean的Web GIS组件概念,并详细阐述其特征、体系结构和空间数据组织;结合实例Internet GIS-GeoSurfV4.0介绍了系统的设计与实现以及二次开发的方法与比较。