椭球变换误差传播模型研究

针对在一些行业性地理信息处理中,基于各种坐标系的数据混用现象普遍存在,而椭球变换误差常被忽略,造成椭球变换对数据产生的影响缺乏科学评价的问题,文章以观测误差传播定律为基本研究工具,推导出椭球变换误差在大地坐标转换误差、地图投影误差、平面距离计算误差中的传播模型,最后以椭球变换误差对空间插值影响为例,对以上模型进行实践应用,研究结果表明,论文推导出的椭球变换误差模型能够成为行业空间信息处理中的椭球变换误差影响评价模型。     

与CGCS2000相联系的独立坐标系建立方法研究

详细阐述利用椭球变换和坐标转换原理建立基于CGCS2000城市独立坐标系的方法,并用实例进行论证。采用此方法建立的独立坐标系,既实现了与CGCS2000的密切联系,又保证了在旧独立坐标系中产生的已有测绘地理信息成果,不经过任何技术处理在新建独立坐标系中能够直接使用,对城市独立坐标系统的改造具有一定的指导意义。     

1980国家坐标系向某市地方独立坐标系的转换

改变国家大地基准参考椭球的参数,以新的椭球作为投影基准,选择合适的中央子午线,通过坐标相似变换的方法,实现1980国家坐标系(1980西安坐标系)向某市地方独立坐标系的转换,并对转换的内符合精度和外符合精度进行了对比分析。     

不同坐标系综合变换法

不同坐标系统的相似变换法一般不足以将两坐标系统间的差异纳入坐标转换模型，因而低精度的坐标框架到高精度的坐标转换往往不能保证统一后的坐标框架的高精度。本文试图将相似变换与回归逼近相结合，以便顾及低精度大地网中的局部误差积累和变形，从而提高统一后的坐标框架的精度。     

不同椭球变换的物理方法

本文采用物理方法讨论不同椭球变换的问题，论证了重力位低阶球谐系数与大地坐标系转换参数的关系，说明几何法转换模型（即大地坐标微分公式）不过是取至二阶次的谐函微分公式，为了提高转换精度，应该采用较高阶次的物理法微分公式（即球面正交多项式）作为不同系统的转换模型。     

大地高误差对Bursa七参数平面转换精度的影响

不同坐标系之间坐标转换,在实际应用中普遍使用Bursa七参数坐标转换模型进行转换.Bursa七参数是三维转换模型,需要重合点的大地高,而大地高通常无法精确获得,大地高误差势必影响转换结果.本文通过具体的试算,研究分析Bursa七参数坐标转换模型中重合点和转换点的大地高误差对转换参数以及转换后的平面结果的影响大小,得出了...     

基于ArcGIS的1980西安坐标系到2000国家坐标系的转换研究

分析了2000国家坐标系与WGS-84坐标系的椭球参数及定向参数,通过实验证实了在ArcGIS中采用WGS-84坐标系的大地坐标代替2000国家坐标系的大地坐标的可行性.本文在自编写的程序中,使用不同大地坐标转换的布尔莎公式计算出了1980西安坐标系与2000国家坐标系的7个转换参数,并将该参数输入到AreGIS的坐标转换参数文件中,从而实现矢量数据与栅格数据从1980西安坐标系到2000国家大地坐标系的转换.通过对转换结果进行精度分析,认为可选用控制测区范围的3～5个转换公共点,使用本文所述方法与流程可以满足1∶1 000或更大比例尺图件的坐标系统转换.     

几种不同坐标变换方法问题的研究

三维或二维坐标转换常采用相似变换，然而相似变换只能解决不同坐标系统之间定义上的差异，坐标系统局部形变系统性误差往往未能反应到转换模型中，因此本文试图从多种变换方法展开讨论，提出了采用相似变换与正形变换的理论解决坐标系统局部形变系统性误差，同时对选择模型参数提出了统计假设检验方法。最后得出一些有益的结论。     

不同投影归算面间的坐标换算

工程控制网坐标与国家大地坐标之间的换算，核心是解决不同投影归算面间的坐标转换。本文采用椭球变换法来分析它们之间的转换关系，较常规的按比例缩放法，精度更高，适用范围更大。     

应用GPS建立区域独立坐标系中椭球变换的研究

阐述了在应用GPS技术建立区域独立坐标系过程中的椭球变换问题。通过椭球变换的广义模型,系统地描述了椭球膨胀法、平移法、变形法三种常用的椭球变换方法,并利用广义大地坐标微分公式从理论角度分析了各方法的共同点和区别,提出了量化分析指标,分别从不同角度反映和量化了椭球变换前后对长度和平面坐标影响的情况。     

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。