基于SINEX解的数据组合及系统误差分析

介绍了采用不同GPS分析中心的SINEX解进行数据组合的处理方法,并采用附加系统误差参数的函数模型对数据组合中的系统误差进行了平差处理.从结果可以看出,估计了Helmert转换参数的测站坐标精度比没有估计Helmert转换参数的测站坐标精度要高,说明本文方法能有效地消除系统误差的影响,并估计了系统误差的大小.     

顾及系统误差的坐标转换方法研究

针对Bursa模型在坐标系转换时没有顾及局部变形和累积误差的问题,通过对坐标转换误差进行分析,本文提出将由此产生的系统误差看作非参数信号的半参数估计,采用半参数模型对某一区域坐标进行解算,并对检核点非参数分量进行推估,与Bursa模型进行比较,结果表明半参数模型能够有效地消除系统误差。并探讨了不同确定平滑因子α的方法对坐标转换精度影响,计算结果表明,在正则矩阵R相同情况下,不同平滑因子确定方法得到的坐标转换精度有所不同,但均优于Bursa模型转换精度。     

阜新市建成区点位坐标转换的研究

在地方坐标系和国家坐标系之间进行平面坐标转换时,由于坐标原点的差异,导致采用简化四参数模型转换坐标时转换矩阵可能出现病态,由此求得的参数解不可靠。基于四参数模型解算时中心点坐标与坐标转换矩阵具有相关性的特点,通过附加中心点坐标可有效地避免转换矩阵病态问题。基于以上原理,本文编程采用阜新市建成区坐标数据进行验证,该方法简单可行,计算结果可靠,转换坐标精度可满足大比例测图图根控制测量精度要求。     

七参数坐标转换中一种削弱高程误差影响的新方法

在较大区域中,利用七参数法实现二维坐标至三维坐标转换时,高程精度影响坐标转换精度。本文提出了一种新方法,可解决七参数坐标转换中高程精度影响平面坐标精度的问题。该方法在无高程情况下,对4°×8°的大区域可实现1 cm左右的转换精度。同时,通过真实测量数据和模拟数据阐明了新方法的可行性和适用范围。     

地形起伏地区平面坐标转换方法及精度分析

坐标转换的精度受转换模型、公共点个数和分布、地形情况等多种因素的影响。本文以青海高原地区某县矿权核查数据为例,采用四参数模型和二次曲面模型进行平面坐标转换,在地形起伏大的大范围区域探讨公共点选取对坐标转换精度的影响,分析两种平面坐标转换模型的特征,为相关的工程应用提供参考依据。     

几种模型在平面坐标转换中的应用

针对在平面坐标转换时选取不同模型将得到不同的转换精度,通过所编程序进行实验,对比了四参数模型、六参数模型和二次曲面模型的转换精度.实验表明,当合理选择转换点时二次曲面模型在平面坐标转换中精度高于四参数模型和六参数模型的转换精度.     

CGCS2000与城市坐标系转换方法的比较

讨论了平面四参数模型、仿射六参数模型和多项式逼近3种坐标转换模型,利用某城市实测数据对这3种模型进行比较与分析。结果表明,当城市坐标系存在一定系统误差和局部变形时,采用多项式逼近法可以提高坐标转换精度,要优于另外2种模型。     

基于CGCS 2000的高斯平面坐标与城市独立平面坐标转换的研究

在假设一种已知重合点坐标无误差情况下,推导了平面四参数坐标转换模型与平面六参数坐标转换模型的公式,该算法无需由误差方程组成法方程。同时,结合城市独立平面坐标与CGCS 2000平面坐标转换算例进行验证,得出了一些有益结论。     

中国局部地区坐标转换与精度评价方法

针对中国东部某地区TWD67坐标系和1954年北京坐标系之间的坐标转换,根据现有资料的收集情况,采用了四参数转换确定平面坐标和七参数转换确定大地高程相结合的转换方法,提高了坐标转换的精度。在没有实测控制点对数据检验的基础上,提出几种方法进行精度评价,通过精度评价结果证实采用这种方法坐标转换的平面精度可以满足大比例尺地图的成图要求。     

平面坐标转换模型的病态性分析与正则化算法

应用数学模型实现坐标系统的转换,转换的精度是人们关注的问题。针对平面坐标转换模型参数间的相关性可能导致的法方程系数矩阵的病态性,该文在非线性平面坐标转换模型的基础上,推导并得出线性转换模型。通过算例对线性转换模型参数的相关性、模型的病态性、及其正则化方法进行分析。结果表明法方程系数矩阵呈病态性,但病态性不是由于模型参数的相关性引起;应用参数的正则化解转换控制点的坐标,其转换精度高于最小二乘解。     

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。