地形可视化的进展与评述

地形可视化由于具有越来越广泛的用途，因此越来越多地引起了大家的关注。本文在简要论述科学可视化、地形可视化定义及其研究内容的基础上，着重讨论了当前地形可视化的表达手段、可视化建模与技术、可视化生成工具、实时地形生成等方面的研究现状及存在的问题，最后对可视化的应用前景和发展趋势进行了展望。     

三维地形的生成技术及实现

概要介绍了三维地形生成的基本技术，结合三维建模软件MultiGen Creator2.4的地形数据库模块，详细讨论了MultiGen Creator2.4中构建地形的四种算法，并以福建省福清地区水口店为研究区域，成功建立了视觉效果较好的三维地形。     

采用Creator生成三维地形

介绍了Creator地形转换的四种算法，讨论了在Creator中生成地形的过程，并以福建省闽清地区水口店为研究区域，建立直观性的、真实性的三维地形。     

几种地形校正方法的研究

本文推证了三种典型的地形校正方法(局部地形改正(C),剩余地形改正(RTM)爱黎-海斯卡宁型地形均衡改正(t_C)之间的数学关系,对其特性进行了分析比较;讨论了它们实现的途径(数据处理方法)及其计算特征;最后还应用某地区的实测地形高数据进行了实际计算,得出了一些有益的结论。     

地形可视化的进展与评述

地形可视化由于具有越来越广泛的用途,越来越多地引起了大家的关注。在简要论述科学可视化、地形可视化定义及其研究内容的基础上,着重讨论了当前地形可视化的表达手段、可视化建模与技术、可视化生成工具、实时地形生成等方面的研究现状及存在的问题,最后对可视化的应用前景和发展趋势进行了展望。     

地形危险区域确定方法的研究

如何利用地形辅助导航给出的准确定位信息和速度信息检索存储的数字地图，预测出前方危险的地形区域，是地形辅助导航有待解决的问题。本文提出了一套通过地形特征分析自动确定地形危险区域的方法：首先提取出描述地形危险区域的一组特征，例如地形坡度变化率、地形粗糙度、地形高程变化率、地形最大高差、地形斜率均方值以及高程均方值等，然后通过地形特征的分析获得地形的危险区域。实验结果证明了本文方法的有效性。     

三维地形可视化技术研究进展

三维地形是虚拟自然环境中不可缺少的因素,也是虚拟仿真领域中视景系统的重要组成部分。该文将地形生成技术概括为三维地形简化技术、大规模地形数据的动态调度与地形简化相结合的处理技术和地形纹理数据的组织与应用技术等三大类,并分别介绍了这三类技术的相关理论和方法。     

虚拟战场地形环境

本文首先描述了虚拟现实技术的基本概念和虚拟现实技术应用于战场地形环境的必要性；其次，概述了虚拟地形环境的国内外发展概况；第三，详细说明了虚拟战场地形环境的主要研究内容，技术难点及解决的基本途径；第四，罗列了研究虚拟战场地形环境的硬软件环境。     

地形危险区域确定方法的研究

如何利用地形辅助导航给出的准确定位信息和速度信息检索存储的数字地图，预测出前方危险的地形区域，是地形辅助导航有待解决的问题。本文提出了一套地形特征分析自动确定地形危险区域的方法：首先提取出描述地形危险区域的一组特征，例如地形坡度变化度，地形粗糙度，地形高程变化率，地形最大高差、地形斜率均方值以及高程均方值等，然后通过地形特征的分析获得地 危险区域，实验结果证明了本文方法的有效性。     

联合战役地形分析

首次提出联合战役地形分析的概念,并分析了联合战役地形分析应用的主要时机和要求。论述确定地形分析基本任务的逻辑关系,并分析研究了联合战役地形分析各基本内容的概念与分析方法。     

阿克苏河-塔里木河水系水质污染遥感监测与评价

 采用Landsat TM数据分析了阿克苏河—塔里木河断面水质污染状况,通过波段的DN值和常规监测数据建立能反映水质状况的 污染物监测模型。结果发现,将2000年常规监测数据代入模型后,与遥感数据的结果基本吻合| 重建阿克苏河—塔里木河的连续水体 污染变化曲线,得出污染物浓度随着远离上游而增加。     

Monitoring drought dynamics in the Aravalli region (India) using different indices based on ground and remote sensing data

The hard-rock hilly Aravalli terrain of Rajasthan province of India suffers with frequent drought due to poor and delayed monsoon, abnormally high summer-temperature and insufficient water resources. In the present study, detailed analysis of meteorological and hydrological data of the Aravalli region has been carried out for the years 1984–2003. Standardised Precipitation Index (SPI) has been used to quantify the precipitation deficit. Standardised Water-Level Index (SWI) has been developed to assess ground-water recharge-deficit. Vegetative drought indices like Vegetation Condition Index (VCI) and Temperature Condition Index (TCI) and Vegetation Health Index (VHI) have been computed using NDVI values obtained from Global Vegetation Index (GVI) and thermal channel data of NOAA AVHRR satellite. Detailed analyses of spatial and temporal drought dynamics during monsoon and non-monsoon seasons have been carried out through drought index maps generated in Geographic Information Systems (GIS) environment. Analysis and interpretation of these maps reveal that negative SPI anomalies not always correspond to drought. In the Aravalli region, aquifer-stress shifts its position time to time, and in certain pockets it is more frequent. In comparison to hydrological stress, vegetative stress in the Aravalli region is found to be slower to begin but quicker to withdraw.     

Landslide risk analysis between Giri and Tons Rivers in Himachal Himalaya (India)

The area around Sataun in the Sirmur district of Himachal Pradesh, India (falling between the rivers Giri and Tons; both tributaries of the Yamuna River) was studied for landslide vulnerability on behalf of the inhabitants. The study was made using extensive remote sensing data (satellite and airborne). It is well supported by field evidence, demographic and infrastructural details and aided by Geographic Information System (GIS) based techniques. Field observations testify that slope, aspect, geology, tectonic planes, drainage, and land use all influence landslides in the region. These parameters were taken into consideration using the statistical approach of landslide hazard zonation. Using the census data of 1991, vulnerability of the populace to the landslide hazard was accessed. As most of the infrastructure in the region is concentrated around population centres, population data alone was used for vulnerability studies.     

Gravity Changes Before Large Earthquakes in China: 1998-2005

Although it is well known that coseismic gravity changes take place during an earthquake, previous research has not yielded convincing evidence demonstrating that significant gravity changes occur before large earthquakes. Furthermore, even if we suspect that gravity changes occur before large earthquakes, we have yet to demonstrate how to consistently observe these changes for useful earthquake forecast that would bring benefits to society. We analyzed ground gravity survey data obtained in 1998, 2000, 200...     

GNSS系统及其技术的发展研究

阐述了国际上卫星导航系统的总体发展,对美、俄、欧、中的四大全球系统,以及相关的区域系统和增强系统进行了简单的介绍,研究分析了GNSS系统及其技术的发展趋势,同时分析了我国Compass全球系统面临的机遇和挑战,并提出了我国未来工作的建议.     

“4D”技术及其应用

介绍“４Ｄ”（即数字地面模型、数字正射影像、数字栅格地图和数字线划地图）系列产品的生产流程、关键技术、及其在耕地保护、防灾减灾救灾和城市规划等方面的应用方法。     

Virtual Australia: its key elements – know,think, communicate

Abstract

Virtual Australia is not a well-defined or agreed concept. This discussion paper conceptualises Virtual Australia as a ‘virtual [digital] model containing and representing all non-trivial objects and their contextual environment – from blue sky to bedrock – in real world Australia’. It describes a scenario for Virtual Australia, one or two decades from now, in which the locations and conditions of non-trivial objects and their environment are updated automatically through a combination of remote sensing and wireless communication technologies in support of a ‘Supranet’. It then examines the concept of the ‘Supranet’ – a pervasive information network based largely on wireless technology linking the physical world to a virtual model in real time – and develops and discusses three principal characteristics of the Supranet: the ability to have or collect specific information (know); the ability to process information (think); and the ability to communicate that information. If, in the near future, any or all non-trivial devices are to some extent able to know, think and communicate, the potential for object autonomy will be realised.     

地理数据库的关系模型及其实现

本文从以图论观点分析地理实体入手,系统阐述了地理数据库关系模型的设计法和过程。作者于1984年4～9月间在微型机上设计建立了关系型地理数据库的实方验系统(RGDB)。该系统采用了本文提出的关系模型,采用了可动态扩库的子库组合结构,这种结构具有灵活性和提高空间利用率的优点。RGDB含有多种功能的数据操作命令,除了具有一般检索功能外,还能进行“开窗”选取和十分“自由”的映象选取。本文对RGDB系统的主要性能和实现途径作了扼要介绍。     

Toward seamless indoor-outdoor applications: Developing stakeholder-oriented location-based services

Location-Based Services (LBS),an emerging new business based on smartphone and mobile networks,are becoming more and more popular.Most of these LBSs,however,only offer non-seamless indoor/outdoor applications and simple applications without giving stakeholders the chance to play an active role.Our specific aim is to solve these issues.This paper presents concepts to solve these issues by expanding the Open Location Services Interface Standard (OpenLS) to allow seamless indoor/outdoor positioning and to extend the content of the services to include information recommended by stakeholders.     

基于WebGL的三维智慧管网系统的设计与实现

随着城市面貌日新月异,地下管网的建设也在持续推进,作为城市的地下“神经网络”,全天24 h保障城市的正常运转和发展。本文以实现城市管网管理系统的高可用、无插件、智能化为目标,采用“地上地下一体”“二三维一体”的设计理念,研究基于WebGL的三维智慧管网系统的关键技术,实现了管线设施管理的信息数字化、空间化与图形化。