TM影像几何校正算法的精度比较

同大多数的线阵推扫式影像相比,TM影像作为双向扫描型的影像其几何校正方法有其特殊性和复杂性。针对这个问题,本文简要介绍了一般多项式、空间斜墨卡托投影、有理函数模型等几种几何近似校正算法,并利用广州地区的TM影像进行了各种试验分析和精度比较。结果表明:同其他方法相比,空间斜墨卡托投影是一种较好的算法,校正精度最高,能够达到一个像素左右,而且该方法不受地形起伏的影响,无需地面高程信息。     

三维城市模型在城镇地籍管理中的应用

地籍管理是土地管理的基础,是国家依法管理土地权属、保护土地所有者和使用者合法权益而采取的行政措施。本文针对当前地籍管理中二维宗地图常因界址不明而引发土地纠纷的现状,在城镇地籍管理中引入了表达直观的三维城市模型。三维空间的交互浏览、界址点、界址线与三维城市模型的叠加、宗地信息的查询以及三维宗地图的制图输出改变了传统地籍管理的模式,在实践中取得了较好的效果,是未来城镇地籍管理的一种重要手段。     

蚀变岩的蠕变特性研究

以某水电站工程项目为依托,利用自行研制的试验仪器对大量的蚀变岩做了单轴压缩流变试验。通过对试验数据的处理和分析,得到了该种岩石的流变,并对蚀变岩的蠕变特性进行了分析总结,为工程设计提供了试验依据。     

Modelling Positional Uncertainty of Line Features by Accounting for Stochastic Deviations from Straight Line Segments

The assessment of positional uncertainty in line and area features is often based on uncertainty in the coordinates of their elementary vertices which are assumed to be connected by straight lines. Such an approach disregards uncertainty caused by sampling and approximation of a curvilinear feature by a sequence of straight line segments. In this article, a method is proposed that also allows for the latter type of uncertainty by modelling random rectangular deviations from the conventional straight line segments. Using the model on a dense network of sub‐vertices, the contribution of uncertainty due to approximation is emphasised; the sampling effect can be assessed by applying it on a small set of randomly inserted sub‐vertices. A case study demonstrates a feasible way of parameterisation based on assumptions of joint normal distributions for positional errors of the vertices and the rectangular deviations and a uniform distribution of missed sub‐vertices along line segments. Depending on the magnitudes of the different sources of uncertainty, not accounting for potential deviations from straight line segments may drastically underestimate the positional uncertainty of line features.     

Open source, spatial analysis, and activity-travel behaviour research: capabilities of the aspace package

This paper reports on recent experience with the development of aspace, an Open Source (OS) library for the geographic visualization and analysis of activity-travel behaviour. The paper begins with an overview of recent progress with respect to the convergence of Open Source technology, spatial analysis, and travel behaviour research. The remainder of the paper focuses on aspace; a collection of functions that, when combined with data describing the geographical location of daily activities, can be used to visualize and describe spatial properties of individual and household activity spaces. These properties include: size, orientation, shape, and the geographical dispersion of activity locations contained within the activity space. Several planar geometries are used to transform measurable spatial properties into intuitive objects for visualizing spatial patterns of activity participation. Experiments are conducted, using data from the first wave of the 2003 Toronto Travel Activity Panel Survey, to demonstrate the potential application of aspace for basic and applied policy-based research into activity-travel behaviour. The toolkit is distributed as a downloadable ‘package’ from the Open Source R Project for Statistical Computing.      

一种基于空间虚拟场景的森林冠层雷达相干散射模型

建立了一种基于分形树和森林动态生长模型的森林冠层雷达相干散射模型.和非相干散射模型相比,相干散射模型不仅考虑了每个散射体的空间位置信息,还保留了后向散射信号中的相位信息.利用已建立的模型模拟了大兴安岭常青林场某一区域白桦纯林的雷达后向散射信号,验证结果说明模型是可靠的,是可以用来反演森林的几何结构和生物物理参数的.     

长江流域沿江镉异常源追踪与定量评估的方法技术研究:以长江流域安徽段为例

长江全流域性的Cd异常是被中国正在进行的多目标地球化学调查发现的重大生态环境问题。以长江流域安徽段为研究对象,对沿江镉异常源追踪与定量评估的方法技术进行了系统研究。通过对安徽段长江干流及其主要支流悬浮物中元素含量的测量查明:悬浮物是流域内重金属元素大跨度迁移的主要载体;Cd在悬浮物中的富集程度远远大于其他重金属元素,这或许正是Cd可以形成沿江流域性异常的主要原因;长江干流悬浮物中重金属元素含量的变化明显受到沿江支流的影响。安徽段长江干流及其主要支流重金属元素输出通量定量计算结果表明:秋蒲河是安徽段重金属元素输出通量最大的支流,每年在安徽段长江两岸土壤中沉积下约4.45t的Cd。利用悬浮物加密测量、1∶5万土壤测量和岩石测量对顺安河流域Cd异常源追踪结果显示:内生金属矿床特别是铅锌矿是悬浮物中Cd的最大的供应源。采用河漫滩沉积物分层采样技术和同位素测年技术,初步恢复了研究区Cd等重金属元素沉积和污染的地球化学历史,对研究区Cd等重金属元素异常的未来演变趋势进行了预警预测。     

UKF算法及其在GPS卫星轨道短期预报中的应用

分析了GPS卫星预报星历,在比较分析EKF和UKF优缺点的基础上,将UKF引入GPS卫星轨道预报研究中.数值模拟和结果分析表明,UKF方法预报更稳定,能有效地提高轨道预报精度和稳定性.     

青藏高原北部新生代陆相盆地石油地质条件及勘探前景

青藏高原北部陆相盆地中烃源岩发育层位包括始新统风火山组、渐新统雅西措组和中新统五道梁组。古近系雅西措组烃源岩,特别是灰岩属于中好烃源岩范畴,有机质类型较好,且烃源岩主体处于成熟阶段,是藏北高原新生代陆相盆地主力烃源岩的发育层位。陆相盆地储集岩较发育,储层较丰富,发育层位包括风火山组和雅西措组,其中雅西措组是储层主力分布层位。对测区分析数据表明：通天河盆地具备一定规模的生油岩厚度,而且有机质丰度为沱沱河地区最高,表明其勘探前景较好。     

大民屯凹陷烃源岩有机质丰度的恢复

烃源岩有机质丰度的恢复具有重要的现实和理论意义。笔者在对比多种方法的基础上,对大民屯凹陷的烃源岩的有机质丰度进行了恢复。