分层信息提取法在县域土地 利用/覆被遥感中的应用

高精度地获取县(或县级市)域土地利用/覆被的定性、定量信息对于维护生态环境和保障我国农村经济的可持续发展具有重要意义。针对2003年冬季所获得的江苏省新沂市的TM图像特点,选择分层信息提取法提取土地利用/覆被信息。首先对图像进行基于最大似然法的监督分类,观察分类结果,提取误分、错分比例最小的未利用地类型,然后采用光谱分析法提取出水体范围、监督分类和目视解译相结合法提取出城镇建设用地和农村居民点、归一化植被指数提取出林地,最后提取出耕地。信息提取结果与同期土地利用图相比较,整个新沂市域范围内土地利用/覆被类型分类的面积精度达到96.17%,空间精度达到88.38%,表明这种方法提取遥感图像土地利用/覆被信息是可行的。     

Synchronising geometric representations for map mashups using relative positioning and Linked Data

Map mashups, as a common way of presenting geospatial information on the Web, are generally created by spatially overlaying thematic information on top of various base maps. This simple overlay approach often raises geometric deficiencies due to geometric uncertainties in the data. This issue is particularly apparent in a multi-scale context because the thematic data seldom have synchronised level of detail with the base map. In this study, we propose, develop, implement and evaluate a relative positioning approach based on shared geometries and relative coordinates to synchronise geometric representations for map mashups through several scales. To realise the relative positioning between datasets, we adopt a Linked Data–based technical framework in which the data are organised according to ontologies that are designed based on the GeoSPARQL vocabulary. A prototype system is developed to demonstrate the feasibility and usability of the relative positioning approach. The results show that the approach synchronises and integrates the geometries of thematic data and the base map effectively, and the thematic data are automatically tailored for multi-scale visualisation. The proposed framework can be used as a new way of modelling geospatial data on the Web, with merits in terms of both data visualisation and querying.     

卫星遥感敦煌地区地表特征参数研究

卫星遥感在研究沙漠化地区非均匀地表特征参数时有其独到的作用。本文提出了一个基于Landsat-7 TM资料推算沙漠化地区地表特征参数的方案，并把其用于中国西北地区“我国重大气候和天气灾害形成及预测理论的研究”的敦煌试验区，并且利用3个景Landsat-7 TM资料进行了分析研究，得到了一些有关沙漠化地区非均匀地表区域地表特征参数(地表反射率、地表温度、修正的土壤调整植被指数MSAVI和植被覆盖度)的新概念。     

基于Landsat/TM资料研究广州城市热岛现象

利用Landsat/TM卫星资料及气象观测资料,基于覃志豪单窗算法对地表温度进行反演,根据热岛强度定义进行热岛强度、热岛范围的定量计算。研究结果表明,在考虑初始地温、总辐射量、植被状况等因素的影响之后,2000年至2005年间,广州市热岛现象呈现明显增强趋势,2000年11月1日、2002年11月7日、2005年11月23日热岛强度指数分别为1.15、1.20、2.89,热岛面积分别为235.44 km~2、261.09 km~2、381.42 km~2。人口增长刺激城市化加剧、温室效应增强使得地表蓄积热量增加是导致广州城市热岛效应增强的主要原因。     

杭州城市生活质量的定量评价

以乡镇、街道为基本空间统计单元,选取人口密度、住宅基准地价、大专以上学历人口比重为社会经济指标,建设用地比重、NDVI、地表温度为生物物理指标,采用主成分分析和GIS叠加法,定量评价了杭州城市生活质量的空间分布状况。结果表明：NDVI和地表温度 (相关系数r = -0.63)、城镇用地比重 (相关系数r = -0.83) 呈明显的负相关,地表温度和城镇建设用地是影响杭州“绿色环境”两个的最重要因素。NDVI和住宅基准地价 (r = -0.66)、大学毕业生比例 (相关系数r = -0.59)、人口密度 (相关系数r = -0.29) 也呈较明显的负相关,“绿色环境”并未成为高学历人群和高收入家庭的主要决定因素,较繁华或较便利地段仍是高学历人群和高收入家庭选择居住环境的首要选择。高生活质量值 (前20%) 区域主要位于分布于城市中心区,即杭州上城区、下城区及西湖区的部分单元,而郊区的生活质量相对较低。     

快速城市化过程中城市土地覆被的时空动态特征

1990~2005年间,是广州市经济快速发展和城市景观变化最大的时期,以同时段TM影像解译得到广州市的土地覆被类型图,从数量结构、空间信息及位置转移和景观等方面,分析了广州市土地覆被的动态特征.数量结构的研究结果显示:在快速城市化过程中广州市的耕地、林地等自然资源的利用程度在加大,自1995年起,这种变化的趋势开始减缓;土地覆被类型之间的信息与位置的转移变化频繁,并且表现出空间位置分异的特征.景观特征指数分析结果表明:广州市城市土地覆被向破碎化方向发展,城市建设用地呈扩展之势.     

对正热电离质谱法硼同位素测定的实验设计和条件优化

为了确定正热电离质谱法测定硼同位素时的最佳实验条件 ,采用均匀设计法进行实验表头设计 ,并用MATLAB进行数据处理和回归模型优化。将最佳优化条件应用于硼同位素测定中 ,得到了与理论计算相吻合的高精度测定结果。     

Vegetative succession and controlled fire in a glades ecosystem A geographical information system approach

Abstract

A geographical information system (GIS) approach was used successfully on a federal wilderness area in southwestern Missouri to examine vegetative succession relative to fire management in a glades ecosystem. Maps of vegetation were obtained by interpreting aerial photographs taken in 1938, 1958, 1966, 1975 and 1986. Maps of topography, streams, soils and the location of fires which burned during the period 1938 to 1986 were also procured from a variety of public agencies. All maps were digitized and incorporated into a raster-based GIS with 25 m pixels. It was concluded that (1) both glades and oak-hickory forest have an affinity for distinct physiographic areas and (2) fire can help decrease the rate of processes of natural succession which cause glades to convert to forest. The probable effects of controlled fire on three areas proposed by the Forest Service were evaluated and summarized.     

Implementing a new data model for simulating processes

The paper describes the development of a new methodological approach for simulating geographic processes through the development of a data model that represents a process. This methodology complements existing approaches to dynamic modelling, which focus on the states of the system at each time step, by storing and representing the processes that are implicit in the model. The data model, called nen, focuses existing modelling approaches on representing and storing process information, which provides advantages for querying and analysing processes. The flux simulation framework was created utilizing the nen data model to represent processes. This simulator includes basic classes for developing a domain specific simulation and a set of query tools for inquiring after the results of a simulation. The methodology is prototyped with a watershed runoff simulation.     

Integrating GIS and data warehousing in a Web environment: A case study of the US 1880 Census

While the business intelligence sector, involving data warehouses and online analytical processing (OLAP) technologies, is experiencing strong growth in the IT marketplace, relatively little attention has been devoted to the problem of utilizing such tools in conjunction with GIS. This study contributes to the development of this research area by examining the issues involved in the design and implementation of an integrated data warehouse and GIS system that delivers analytical OLAP and mapping results in real‐time across the Web. The case study chosen utilizes individual records from the US 1880 population census, which have recently been made available by the North Atlantic Population Project. Although historical datasets of this kind present a number of challenges for data warehousing, the results indicate that the integrated approach adopted offers a much more flexible and powerful analytical methodology for this kind of large social science dataset than has hitherto been available.