A Local Example of Land‐Use Change: Southern Illinois—1807, 1938, and 1993*

This article provides an analysis of a wetland site in southern Illinois from presettlement to the present. The study area is part of the Cache River‐Cypress Creek Wetland, which has international importance, as recognized by the Ramsar Convention on Wetlands. Land‐cover data for 1807, 1938, and 1993 were created and analyzed with a geographic information system (GIS). Land‐use change by topographic setting (uplands, transitional, and bottomlands) and soil productivity was quantified and studied. Interviews with local experts informed this analysis. Results illustrate the complexity of environmental change and its driving forces. First, notable forest and swamp acreage was converted to cropland between 1807 and 1938 and, to a lesser degree, from 1938 to 1993. Second, there were land‐use variations by topographic region. Between 1807 and 1938, the largest transformation occurred in the uplands, with substantial acreage converted from forest to cropland. Between 1938 and 1993, however, agriculture decreased in the upland areas as hilly areas reverted to forest cover. At the same time, agriculture expanded in the bottomlands as this land was drained for farming. Third, there are interesting patterns within these categories of land‐use change, as soil productivity is an indicator of what lands were taken out of cropland and converted back to grassland and forest.     

A Place for Geography in the Liberal Arts College?

This study charts the presence of geography at liberal arts colleges and explores the relationship between the liberal arts and the study of geography. The results of this study reveal a paradox: geography embodies many of the ideals of a liberal arts education and yet this study indicates an absence of degree‐granting geography programs at 93% of institutions. Geography thrives, however, at a select group of liberal arts colleges, and these colleges are disproportionately important as the undergraduate origin for doctorate recipients in geography.     

GIS中矢量与栅格数据模型比较

由于GIS软件的多样性，每种软件都有自己特定的数据模型，从数据结构上来说，矢量和栅格是地理信息系统中两种主要的空间数据结构。本文通过对栅格数据与矢量数据模型的应用比较．对于空间数据从需求分析，以满足对数据信息进行更改、更新、增加或者为了某种特定的需要。     

基于GIS的地下水水源地补给潜力探讨

本文提出了一种基于GIS的补给潜力分析方法。在实例研究中,通过对地形、地表物质组成、包气带岩性、植被覆盖等因子建立的专题图层的叠加分析,确定了地下水的补给潜力分区,结合研究区含水层分布特征,综合确定了水源地的靶区和开采潜力区。研究表明,利用GIS确定研究区降雨入渗补给量是一种高效、直观、可行的方法。     

A new magnitude category disaggregation approach for temporal high‐resolution rainfall intensities

Simulation of quick runoff components such as surface runoff and associated soil erosion requires temporal high‐resolution rainfall intensities. However, these data are often not available because such measurements are costly and time consuming. Current rainfall disaggregation methods have shortcomings, especially in generating the distribution of storm events. The objectives of this study were to improve point rainfall disaggregation using a new magnitude category rainfall disaggregation approach. The procedure is introduced using a coupled disaggregation approach (Hyetos and cascade) for multisite rainfall disaggregation. The new procedure was tested with ten long‐term precipitation data sets of central Germany using summer and winter precipitation to determine seasonal variability. Results showed that dividing the rainfall amount into four daily rainfall magnitude categories (1–10, 11–25, 26–50, >50 mm) improves the simulation of high rainfall intensity (convective rainfall). The Hyetos model category approach (Hyetos_Cat) with seasonal variation performs representative to observed hourly rainfall compared with without categories on each month. The mean absolute percentage accuracy of standard deviation for hourly rainfall is 89.7% in winter and 95.6% in summer. The proposed magnitude category method applied with the coupled Hyetos_Cat–cascade approach reproduces successfully the statistical behaviour of local 10‐min rainfall intensities in terms of intermittency as well as variability. The root mean square error performance statistics for disaggregated 10‐min rainfall depth ranges from 0.20 to 2.38 mm for summer and from 0.12 to 2.82 mm for the winter season in all categories. The coupled stochastic approach preserves the statistical self‐similarity and intermittency at each magnitude category with a relatively low computational burden. Copyright © 2014 John Wiley & Sons, Ltd.     

ArcSDE在基础地理信息数据库更新中的应用

在国家1∶50 000地形数据库动态更新过程中,笔者通过总结"十二五"期间传统地形数据库的更新方法,提出了基于ArcSDE的、支持多用户分布式在线整理、编辑地形数据库的新方法。本文以朝阳市作为研究对象,通过ArcSDE构建支持集中管理、多用户同步编辑和更新的数据库处理平台,完成了2015年朝阳市1∶50 000地形数据库的更新工作,与以往传统更新方法相比,该方法节省作业时间,提高了工作效率。     

甘肃省第一次全国地理国情普查数据库设计

地理国情普查数据库是地理国情普查成果数据存储、管理和分发应用的基础,为地理国情动态监测提供本底数据库。本文从甘肃省实际情况出发,结合信息化测绘服务体系和"天地图·甘肃"等现有成果,从数据库概念设计、逻辑设计、物理设计、接口设计,以及数据库管理系统和地理国情展示系统等方面进行了详细的设计,为全面开展地理国情普查数据库建设奠定了坚实的基础。     

地理世情监测标准建设初探

探讨地理世情监测标准规范建设的需求与意义,归纳梳理国内外相关标准规范建设的现状,分析目前我国地理世情监测标准规范建设存在的不足,提出相关建议,以推动地理世情监测工作的开展。     

浅析GIS的地下管线查询与管理系统

城镇地下管线就像是城镇的脉络,对于城镇的运转非常重要,肩负着为城镇运送物质能量、输出废弃物的重要使命。随着城镇的扩建,敷设于地下的管线不断向周围扩张,其规模不断膨胀,因此,也变得越来越复杂。传统的管线管理方式不仅数据的查询效率低,导致因管线错挖而造成的爆管事故频发,而且不能及时准确地进行应急处理。所以在告别传统落后的地下管线管理方式的同时,我们应思考如何能够更好的管理大量的地下管线数据,从而提高了数据的查询与应急管理的效率,为城镇规划和发展提供更好的支撑作用。     

浅谈基于Android的移动地理信息采集系统建设

阐述了Android平台下调用GPS定位的方式方法,提出了PC端空间数据文件shapefile至Android平台可识别的SQLite数据库的转换方法和技术手段。通过Arc GIS SDK for Android移动GIS类库组件对SQLite数据库解析成Graphic图层,实现了地图属性编辑查看功能,并通过调用Android移动设备的拍照功能,将照片文件关联到属性信息,丰富地理信息数据的内容,实现地理信息数据的移动终端采集。