基于GDI+的复杂线状符号优化算法

本文针对用GDI+开发地图图式符号库时,绘制复杂线状符号存在的转角问题,即在线段/线段连接处标注符号不均匀的问题,提出了一种基于单位距离的线状符号绘制方法.设计了参数化的数据结构,提出基于单位距离的符号定位点的快速确定算法,较好地解决了利用GDI+开发地图线状符号时遇到的转角问题.该优化方法不但提高了复杂线状符号的显示...     

AutoCAD二次开发应用于地形图符号转换的研究

针对国家标准大比例尺地形图新版图式推广以后带来的符号变化,利用AutoCAD组件二次开发的独立程序进行自动处理,快速高效地完成已有AutoCAD电子地图成果中绝大部分符号转换工作,并对其优缺点进行评价。     

地图集编制过程中相关问题的探讨

结合笔者的实践,重点介绍了在地图集编制过程中解决的关键性技术问题,如数据的坐标转换、数据格式转换、符号替换、图幅裁切等。     

修订“国家系列比例尺地形图图式”有关问题的探讨

地形图图式是地图制作、使用、更新、建库的基础，因此，对地形图图式进行全面的修订，是一项涉及到我国新一代地形图模式的重要工作。对地形图图式修订过程中所涉及到的诸如色彩的设置、公路的分级、居民地的简化、符号的增删等有关问题进行讨论，以期达到抛砖引玉，集思广益之作用。     

对我国现行图式符号军用价值的初步检验及修改意见

本文着重讨论了对我国现行图式符号进行军用价值检验的必要性;提出了检验的依据和原则;择要说明了我国现行图式符号存在的主要问题;并提出了改进意见,供修改图式符号之参考。     

MapInfo和AutoCAD符号转换的初步探讨

本文结合工作实践,对ＭａｐＩｎｆｏ和ＡｕｔｏＣＡＤ间图形数据的组织及相互间的交换进行了分析,并针对符号数据转换过程中存在的主要问题,提出了一些解决方法。     

基于基础地理信息的数字地图制图系统

基于国家基础地理信息,实现数字环境下的自动地图制图,是目前地图学研究的关键问题之一。本文根据国家现有图式表达规范,建立相应的符号库,实现地图的符号化,并以自动或半自动化方式解决符号配置过程中要素之间的各种关系;实现了点状、线状及面状注记的自动配置及移位处理,解决了地图的图外整饰配置与显示,初步实现了数字环境下普通地图的自动化制图。     

地形图修补测内业整饰常见问题

近年来测绘事业飞速发展,地形图图式已有部分更新。随着数字城市工作的逐步推进,入库工作显得尤其重要。对地形图修补测中旧图式图形改为新图式及其入库方面出现的常见异常问题做一总结,并提出了解决办法。内容主要涉及到图式符号的改变、地形地物属性表的操作、图形实体授权以及其他疑难问题。     

“伪地心距”概念的提出及其精度分析

为解决重力计算中的坐标转换与精度分析问题,通过对ECEF坐标系中的地心球坐标、地心直角坐标和大地坐标三者之间的转换关系的分析,得出了转换过程和转换公式。针对实际工作中遇到的一种特殊已知条件下的坐标转换问题,提出了“伪地心距”的概念,给出了计算点在参考椭球面上和外部两种情况下坐标转换的方法及解决实际问题的办法,并对伪地心距的具体变化规律进行了计算分析。     

对图式沙漠符号的建议

根据过去在塔里木沙漠及准噶尔沙漠工作的初步体验,感到现行1:25000～1:100000地形图图式所订定的沙漠符号,尚未能满足实际需要,图式解说对这方面的内容还嫌不够。现根据本人在实际工作中之体会,提出沙漠地区图式符号的意见,以供修改图式时之参考。     

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.     

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.     

GIS空间数据的采集误差及其分析

本文详细阐述了GIS数据采集过程中的误差来源，重点分析了通过地图、遥感和摄影测量等方式采集数据所产生的误差及其特性，分析了其对GIS数据的影响与消减方法。     

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。