用Motif工具库设计地震正演模拟系统人机交互界面

Ｍｏｔｉｆ的功能概要地说就是对各种Ｗｉｄｇｅｔ的创建、管理和回调。利用Ｍｏｔｉｆ工具库为该系统设计人机交互界面的主要步骤为：根据有限元法地震正演模拟系统的总体结构,编程设计系统各层次结构的接口界面,主要包括主窗口、菜单拉杆、下拉菜单和绘图基的创建以及模型数据输入和图形的绘制。有限元法地震正演模拟系统的总体结构由四个层次的内容组成,其主要功能是：输入模型参数和排列参数（包括激发、接收参数）;进行有限元法地震正演模拟计算;修改模型参数并重新进行计算。     

时空过程网络可视化模拟与分析服务——以溃坝洪水为例

洪水溃坝等复杂灾害现象的时空过程模拟分析,是当前国际地理信息科学热点研究方向之一。随着网络的普及化,公众对GIS时空分析模型的网络实时集成和可视化分析提出了迫切的需求。本文以溃坝洪水为例开展了时空过程网络可视化模拟与分析服务研究,利用Web GL、HTML5、Ajax、Web Service、GPU并行计算等技术手段,通过探讨溃坝洪水时空模型计算优化、网络三维可视化模拟与动态交互分析等关键技术,研发了原型系统并进行应用实验。实验结果表明,本文研究成果有助于实现时空过程信息的网络发布,在线影响分析及动态可视化服务,可为分布式网络环境下溃坝洪水等时空过程信息管理和应急决策提供科学依据和技术支持。     

基于BDS导航数据更新系统的设计与实现

以提高导航数据更新效率为目的,研究了导航数据采集与更新系统的设计与实现。该系统以VS-NET为开发平台,依靠北斗卫星导航系统定位数据,以ArcGIS Engine-组件式GIS作为地理信息系统软件,采用C#语言作为开发设计工具,实现了导航数据更新的操作便捷、高效、准确。本文重点介绍了系统功能设计和功能实现过程。     

REVIEWS OF GEOGRAPHIC SOFTWARE

Geographic Software Reviewed in this article: THE DIFFUSION GAME . Christopher J. Lovelock and Charles B. Weinberg . MAPIT . Raymond J. Kalush , Jr . SIMODEL . Peter A. Williams and A. Stewart Fotheringham . WEATHER FRONTS . P. C. Moyer . WORLD DYNAMICS . Mark Lewis Baldwin     

Pyroclastic Flow Hazard at Volcán Citlaltépetl

Volcán Citlaltépetl (Pico de Orizaba) with an elevation of 5,675 m is the highest volcano in North America. Its most recent catastrophic events involved the production of pyroclastic flows that erupted approximately 4,000, 8,500, and 13,000 years ago. The distribution of mapped deposits from these eruptions gives an approximate guide to the extent of products from potential future eruptions. Because the topography of this volcano is constantly changing computer simulations were made on the present topography using three computer algorithms: energy cone, FLOW2D, and FLOW3D. The Heim Coefficient (), used as a code parameter for frictional sliding in all our algorithms, is the ratio of the assumed drop in elevation (H) divided by the lateral extent of the mapped deposits (L). The viscosity parameter for the FLOW2D and FLOW3D codes was adjusted so that the paths of the flows mimicked those inferred from the mapped deposits. We modeled two categories of pyroclastic flows modeled for the level I and level II events. Level I pyroclastic flows correspond to small but more frequent block-and-ash flows that remain on the main cone. Level II flows correspond to more widespread flows from catastrophic eruptions with an approximate 4,000-year repose period. We developed hazard maps from simulations based on a National Imagery and Mapping Agency (NIMA) DTED-1 DEM with a 90 m grid and a vertical accuracy of ±30 m. Because realistic visualization is an important aid to understanding the risks related to volcanic hazards we present the DEM as modeled by FLOW3D. The model shows that the pyroclastic flows extend for much greater distances to the east of the volcano summit where the topographic relief is nearly 4,300 m. This study was used to plot hazard zones for pyroclastic flows in the official hazard map that was published recently.     

Demographic Transition: Threat to Developing Nations

Abstract

As computers become commonplace in the nation's schools, interactive maps are finding their way into the geography classroom. Students can use electronic atlases to access information as well as use authoring software to produce their own interactive maps. Does this change in media correspond to better geography education for our children? This article addresses whether using interactive maps for gathering and presenting information can have a positive influence on learning geography content. A two-week experiment was conducted in five 7th grade classrooms. Students in four of the classes researched and produced map products using both traditional and computer-assisted techniques. The fifth class was a control group. A pretest and two post-tests were given to quantitatively assess student learning after each project. Also, students were given a qualitative questionnaire to determine their attitude towards the different techniques. Quantitative results of the study indicate that there was no significant difference in student post-test performance after using each of the techniques, but qualitative results suggest that students prefer using the computer techniques over the traditional methods for gathering and presenting information.     

Formation of an Interactive User-Oriented Forecasting System: Experience from Hydrological Application in Linyi, Eastern China

Having provided an overview of the ideas of developing user-oriented interactive forecast system (UIFS) emerging in recent years,the authors proposed an idealized framework of the new-generation meteorological system,which includes the initial user-end module for configuring the forecast target,the physical predictive and downscaling components,and an incessant assessing module in association with decision-making at the user-end.A case study was carried out with a focus on applying the TIGGE (THORPEX Interactive Grand Global Ensemble;THORPEX stands for The Observing System Research and Predictability Experiment) precipitation forecasts for the hydrological users in Linyi,a region richest in rivers and reservoirs in eastern China.The preliminary results exhibited great potential of improvement in applications of weather forecasts by combining the user-end information.Although the TIGGE results provided by existing national/international operating models were independent from the user-end,the case study enlightened ways of establishing an iteratively self-improving UIFS involving user-orientation throughout the forecast process.     

基于交互式分割技术和决策级融合的SAR图像变化检测

为免去去除斑点噪声的预处理操作及克服选择分布模型的限制,本文结合差异图的特点和一种不涉及分布模型的交互式分割方法,产生不同“种子点”下的变化检测结果后,再利用投票策略对其进行决策级的融合给出最终的变化检测结果。分割中,将每个像素的特征设为差异图及由静态小波变换分解差异图再丢弃高频系数后重构得到的各层表示中,其对应位置上的灰度值构成的矢量。此特征及决策级融合的策略使本文的变化检测技术对SAR图像中的斑点噪声具有一定的鲁棒性。在无需对SAR图像做预处理的情况下,对真实SAR图像数据集的变化检测结果,其效果优于其他相关技术的。     

“摄影与航空摄影”课程互动式教学模式的研究

互动式教学模式以培养学生学习的自主意识和创新能力为目标,既发挥教师的主导作用,又充分体现学生的认知主体作用。摄影与航空摄影是遥感科学与技术专业的专业基础课程,本文提出了针对该课程的互动式教学模式,并进行了课堂教学实践,总结了该模式的创新点和应用价值。     

都市区空间结构与经济发展的互动关系研究

文章采用结构方程模型实证检验空间结构与经济发展的互动关系。研究发现,中国都市区已经进入多中心分散阶段,空间结构与经济发展存在因果关系,即经济发展水平的提高会扩大人口规模,规模增加则导致集聚不经济上升,并促进空间结构多中心化。多中心化后的空间结构由于降低了集聚不经济而进一步提高生产率。因而,传统地理学中关于两者互动发展的描述得到实证支持;同时明确了多中心化的直接动力是人口规模的增加,而不是经济发展水平的提高。这些发现对于优化当前中国的城市与区域空间战略具有重要的启示。