GIS中三维空间直线的误差熵模型   总被引：1，自引：0，他引：1  

朱长青  张国芹  王光霞 《武汉大学学报(信息科学版)》2005,30(5):405-408

从信息熵的角度提出了三维空间直线的误差熵模型，该模型由以垂直直线的平面误差熵为半径的圆柱体和两端点的误差球组成，是一种完全确定的度量空间线元不确定性的模型。理论分析与实验表明，本文所提出的模型具有较好的效果。  相似文献   

重复轨道差分干涉测量参数模型的建立     

李陶  刘经南  廖明生 《武汉大学学报(信息科学版)》2005,30(8):744-747

以高斯-马尔柯夫模型的随机模型为基本框架,在差分干涉数学模型的基础上,对应于DEM生成过程和形变提取过程,分别定义了由高程引起的相位模糊度和由形变引起的相位模糊度,并提出了相应的解缠算子约束条件,完善了差分干涉测量的基本数学模型。根据完善后的数学模型,推导了差分干涉测量基本的两轨、三轨、四轨算法的模型公式,并对其中的误差源进行了相应的理论分析。  相似文献   

GPS动态监测中多路径效应的规律性研究   总被引：14，自引：1，他引：14  

黄声享  李沛鸿  杨保岑  向东 《武汉大学学报(信息科学版)》2005,30(10):877-880

在分析GPS多路径效应特性的基础上,结合GPS动态变形监测的特点,对连续多天的观测数据解算结果采用滤波与周日位置求差相结合的方法进行数据处理。研究结果表明,多路径误差具有较强的周日重复性,在有效地削弱多路径效应的影响后,GPS动态监测的三维位置精度可以达到mm级,尤其是垂直方向的精度改善明显。  相似文献   

HDF 5格式特点及其对遥感数据格式标准化的几点启示   总被引：3，自引：0，他引：3  

王永韬  刘良明 《国土资源遥感》2005,16(3):39-43

阐述了HDF 5数据格式的特点及其对遥感数据标准化的启示和借鉴作用。HDF 5格式层次式的逻辑结构、B树的物理存储方式，面向对象的特性、数据类型的广泛支持、自我描述以及内容与表达的分离等特点，使得它在记录和存储科学数据时具有强大的优势。遥感数据标准化如何设计一种结构简单且扩展性很好，同时支持不同平台的标准格式，可以从HDF 5的实现方法上得到借鉴。  相似文献   

数码相机内参数的实验场法标定   总被引：6，自引：1，他引：6  

黄桂平李小勇  钦桂勤 《测绘学院学报》2005,22(3):163-165

介绍了数码相机的径向畸变、偏心畸变和像平面内仿射畸变对像点影响的畸变羞模型；采用实验场法对内参数进行了标定；通过一系列实验，得到了一些有益的结论。  相似文献   

扫描数字化对点误差的统计特性试验与分析     

郭同德  曹进克 《测绘学院学报》2005,22(3):226-228,231

研究了通过扫描数字化试验，获取了GIS中特征点对点误差的基础数据，分析了误差的成因，讨论了误差的分布规律和统计特性，为扫描数字化精度控制及数据质量的评价提供了参考依据。  相似文献   

Advances in carbon flux observation and research in Asia   总被引：7，自引：0，他引：7  

YU Guirui  ZHANG Leiming  SUN Xiaomin  FU Yuling  LI Zhengquan 《中国科学D辑(英文版)》2005,48(Z1)

As an important component of FLUXNET, Asia is increasingly becoming the hotspot in global carbon research for its vast territory, complex climate type and vegetation diversity. The present three regional flux observation networks in Asia (i.e. AsiaFlux, KoFlux and ChinaFLUX)have 54 flux observation sites altogether, covering tropic rainforest, evergreen broad-leaved forest, broad-leaved and coniferous mixed forest, shrubland, grassland, alpine meadow and cropland ecosystems with a latitudinal distribution from 2°N to 63°N. Long-term and continuous fluxes of carbon dioxide, water vapor and energy between the biosphere and atmosphere are mainly measured with eddy covariance technique to (1) quantify and compare the carbon, water and energy budgets across diverse ecosystems; (2) quantify the environmental and biotic controlling mechanism on ecosystem carbon, water and energy fluxes; (3) validate the soil-vegetation-atmosphere model; and (4) serve the integrated study of terrestrial ecosystem carbon and water cycle. Over the last decades, great advancements have been made in the theory and technology of flux measurement, ecosystem flux patterns, simulation and scale conversion by Asian flux community. The establishment of ChinaFLUX has greatly filled the gap of flux observation and research in Eurasia. To further promote the flux measurement and research,accelerate data sharing and improve the data quality, it is necessary to present a methodological system of flux estimation and evaluation over complex terrain and to develop the integrated research that combines the flux measurement, stable isotope measurement, remote sensing observation and GIS technique. It also requires the establishment of the Joint Committee of Asian Flux Network in the Asia-Pacific region in order to promote the cooperation and communication of ideas and data by supporting project scientists, workshops and visiting scientists.  相似文献   

Eddy flux corrections for CO2 exchange in broad-leaved Korean pine mixed forest of Changbai Mountains   总被引：1，自引：0，他引：1  

WU Jiabing  Guan Dexin  SUN Xiaomin  YU Guirui  Zhao Xiaosong  HAN Shijie  JIN Changjie 《中国科学D辑(英文版)》2005,48(Z1)

Based on analysis of mechanisms causing energy no-closure and nocturnal low fluxes issues for CO2 exchange studies by eddy covariance method, corrections were done with the raw data sets obtained from Changbai Mountains forest flux site, to evaluate the impacts of sonic anemometer tilt, frequency response limitations and advection on estimation of CO2 exchange, respectively. The results show that the planar fit coordinate transforming method is superior to the streamline coordinate transforming method in tilt correction. The latter could cause a systematical underestimation of eddy fluxes relating with the angle of sensor and terrain tilt. The underestimation of CO2 and energy fluxes for frequency response limitations average 3.0% and 2.0% during daytime, respectively, which increase by 9.0% and 5.5% during nighttime, respectively. The corrections of frequency response limitations are closely related to atmospheric stability. The advection loss of CO2 fluxes is dominated by nocturnal vertical advection, which is at least 18% when the horizontal advection is neglected. It is suggested that more work be done to understand the characteristics of horizontal advection and turbulent eddies under a complexcircumstance.  相似文献   

Comparison of Linear Regression Models for Quantitative Geochemical Analysis: An Example Using X-Ray Fluorescence Spectrometry   总被引：1，自引：0，他引：1  

Mirna Guevara  Surendra P. Verma  Fernando Velasco-Tapia  Rufino Lozano-Santa Cruz  Patricia Girón 《Geostandards and Geoanalytical Research》2005,29(3):271-284

This paper presents statistical aspects related to the calibration process and a comparison of different regression approaches of relevance to almost all analytical techniques. The models for ordinary least-squares (OLS), weighted least-squares (WLS), and maximum likelihood fitting (MLF) were evaluated and, as a case study, X-ray fluorescence (XRF) calibration curves for major elements in geochemical reference materials were used. The results showed that WLS and MLF models were statistically more consistent in comparison with the usually applied OLS approach. The use of uncertainty on independent and dependent variables during the calibration process and the calculation of final uncertainty on individual results using error propagation equations are the novel aspects of our work.  相似文献   

Dynamic Displacement of a Block on an Inclined Plane: Analytical, Experimental and DDA Results   总被引：1，自引：1，他引：1  

M. Tsesarsky  Y. H. Hatzor  N. Sitar 《Rock Mechanics and Rock Engineering》2005,38(2):153-167

  相似文献