GIS与土壤溶质运移模型结合研究进展

地理信息系统对土壤溶质模型研究而言,使用者的要求与GIS所能提供的功能之间,还存在巨大的差距。出于对环境问题的关注,土壤中水分及溶质运移的规律及其对环境的影响,成为当前研究的热点。随着对土壤溶质运移模型研究的深入,一方面由于田间土壤特性具有很大的空间变异;另一方面,在实际应用中,往往溶质运移的宏观特征而非微观特征,具有更重要的意义。将溶质运移模型与GIS技术结合,定量研究空间尺度的溶质运移,成为溶质运移研究的必然发展趋势。由于计算机软硬件技术的发展,GIS正处于一个高速发展的时期。将GIS与溶质运移模型相结合,或者进一步,以GIS理论和技术为基础,建立基于GIS的溶质运移模型,将对溶质运移的规律及其对环境的影响,做出更深入和准确的描述。     

基于GIS的中国人居环境自然适宜性评价

With the degeneration of environment and acceleration of urbanization, human environment has attracted great attention worldwide. This paper sets up the Human Settle-ments Environment Index (HEI) model and evaluates the natural environment suitability for Human Settlements in China based on GIS technology. The results show that the HEI of China decreases from southeast to northwest in general, HEI is significantly correlated with population density at grid size and the correlation coefficient (r) between them reaches 0.93, which indicates that natural environment suitability for Human Settlements has a significant influence on population distribution. Most people in China mainly concentrate in areas with high natural environment suitability. The total suitable area is 430.47×104> km2, which ac-counts for nearly 45% of the total land area in China, while the proportion of people living in the area reaches 96.56%. With a population density of 18 people per square kilometer, the critical area is the transitional region for people to live in China. The critical area covers 225.11×104 km2 with a population of 41.12 million. The non-suitable area covers 304.42×104 km2 with a population of only 2.49 million.     

南水北调中线工程水源区农耕地分等定级研究

选取了坡度、土地利用类型、土壤类型、海拔高度、坡向等5个主导评价因子.采用等差指数多因子综合分析与最低限制性因子分析相结合的方法,利用ARCGIS 9.0软件提取相关信息,对南水北调中线工程水源区农耕地进行了分等定级.结果表明,最适宜和中度适宜的土地面积分别占3.4%和36.5%,以中低产田为主;临界适宜和不适宜的土地面积占16.8%和43.4%,具有潜在的宜林宜牧利用价值.研究结果对于水源区制定农业发展政策,科学合理、高效利用土地尤其是耕地资源,实现生态环境保护与经济的协调发展具有重要意义.     

Exploring the Spatiotemporal Pattern of Cyberbullying with Yik Yak

Cyberbullying is an emerging social issue along with the prevalence of social media. Previous studies have used extensive surveys or firsthand data primarily from conventional social networks¹1 Social media whose users primarily use their real name and provide identifiable information, although some might use pseudonyms (e.g., Facebook and Twitter).View all notes (e.g., Twitter) to study cyberbullying, which often ignores the factor of anonymity and location. Considering the sensitive nature and contagious effect of cyberbullying, a better understanding of the spatiotemporal pattern in cyberbullying is sorely needed to develop effective policies to combat this toxic social behavior. Grounded in the dramaturgy theory and the emerging literature on technoself, this study aims to compare cyberbullying in the anonymous social media (Yik Yak) with the conventional social media (Twitter) and explore its spatiotemporal patterns. A support vector machine is used to help identify records with bullying content. Average nearest neighbor, kernel density, and Ripley's K-function are used to explore the spatiotemporal patterns of cyberbullying behavior. We have found that cyberbullying is more likely to occur in anonymous than conventional social media. We also detected a clustering pattern corresponding to the student population, which can be explained by the dramaturgy theory and recent studies on technoself. In addition to making suggestions to help reduce cyberbullying in the future, this article also sheds light on the need for future studies.     

基于MapServer的教育地理信息系统构建

基于Web的教育地理信息系统(EDUGIS)是教育信息化建设的重要组成部分.本文以WebGIS开源平台MapServer为框架,设计了教育地理信息系统的框架和功能结构.引入Ajax技术的组织结构,并结合开源数据库PostgreSQL开发了网络教育地理信息系统.该系统可以直观地对各种形式的教育地理信息进行显示和查询,对教...     

Spatial-temporal differences in in-stream flow requirement based on GIS： A case study of Yan＇an region,northern Shaanxi

Although water has the central function of the bloodstream in the biosphere especially in arid or semi-arid regions such as Yah＇an region in northwestern China, yet the very limited attention is paid to the role of the water-related processes in ecosystem. In this research, based on continuous nearly 50-year data including runoff volume, sediment discharge as well as sediment accretion from hydrographic stations, and 10-year information of water quality from pollution monitoring stations, the method for measuring in-stream flow requirement has been put forward supported by experiential models and GIS spatial analysis. Additionally, the changes of in-stream flow requirement for environment and economic development have been addressed from spatial-temporal dimensions. The results show that： （1） According to the central streams in Yan＇an region, mean annual in-stream flow requirement reaches 1.0619 billion m^3, and the surface water for economic exploitation is 0.2445 billion m3 （2） Mean annual in-stream flow requirement for sediment transfers in flood period occupies over 80% of the integrated volume in a year. （3） From the 1950s to 1970s, in-stream flow requirement for sediment transfers is comparatively higher, while from the 1980s to 1990s, this requirement presents a decreasing tendency.     

广东省科技产业信息可视化分析

在分析传统广东省科技产业信息表达不足的基础上,本文引入GIS进行广东省科技产业信息可视化表达分析.首先,以.net作为开发平台,ArcGIS Engine作为GIS平台,构建了基于GIS的广东省科技产业信息可视化系统,实现广东省科技产业数据存储与管理、查询、统计、专题图分析等功能,直观地再现了广东省科技产业信息在空间、...     

基于Web GIS的广州市人防工程地理信息系统研制

分析基于java的Web GIS的技术发展和实现方法,在此基础上,结合广州市人防工程地理信息系统的研制实践,研发出一个人防工程地理信息原型系统,该原型系统实现了C/S 和B/S的有机结合、安全性和实用性有效结合,解决了矢量化地图的操作、图形和人防属性数据双向查询、统计、专题图、统计图制作、人防工事分布分析及规划等问题,对于提高人防工程信息化的管理具有广泛的社会应用价值.     

贝塞尔曲线在虚拟森林景观单树几何模型构建中的应用

虚拟景观模型的生成,需要对实际景观进行抽象和简化。树几何模型和数字高程模型(DEM)是构成虚拟森林景观的两大要素。而树几何模型的构建又是林业GIS三维可视化的基础。在树几何建模中,树干及树枝形状的可视化表达具有突出意义。由于实际树种的复杂性,在计算机中建树模型,通常采用基于过程建模的方式,而这将面临用户如何对模型进行交互式控制的问题：参数太少,不足以描述树形态特征,而参数太多,则模型难以生成和理解。为了解决这个问题,我们引进贝塞尔(Bezier)曲线这种基于控制点的自由曲线来描述树木中的树干以及树枝形状,利用对曲线控制点的变动来控制曲线的形状,进而生成形态各异的树形状,对此,我们基于ActiveX技术生成Bezier曲线控件。结果表明,该方法能够表示多种形状的树干与树枝,具有操作简捷、计算速度快,可视化效果良好的优点。     

资源勘查图件计算机辅助编绘系统的结构分析与开发策略研究

如何站在信息系统的高度来进行资源图件计算机辅助编绘系统的快速开发,是资源信息系统领域计算机应用的一个重要研究课题。在结构分析的基础上,将资源图件计算机辅助编绘系统划分为图形数据库,应用图形系统和基础图形系统3个基本部分。对于复杂资源图件的计算机辅助编绘,需要地矿点源信息系统的支持。在基础图形系统上进行专业编绘程序的二次开发是高效建立图件编绘系统的最佳途径,并需注意GIS集成应用,三维可视化,人工智能和参数化设计等方法的运用,而系统平台开发是复杂应用的高级阶段。该思想可应用于煤及油气勘探,工程开发,矿区管理及区域地质等诸多领域的软件开发中。