一个应用于近景摄影测量的模型

模型建立是工程设计中的重要环节。本文描述了一个专门应用于近景摄影测量的算法，该算法基于人的行为来模拟手持摄影仪的姿态。本文给出了该算法和一个数值实例，尝试将该算法运用于ＣＡＤ系统，取得了令人满意的初步效果。     

为亚诺河工程设计的一个分布式多媒体信息系统

本文描述了基于委托器范例的一个多媒体信息系统体系。构想此系统是为了收集，共享和有效地管理空间多传感器遥感影像和地面数据，并通过一个网络传播，即使本文仅谈及一个特定的应用实例，但这个系统体系包括了一些概念，举例证明了它们对于在空间信息科学中进行信息系统的开发和集成，以及促进摄影测量和遥感应的发展是十分方便的。     

湖州市GPS基础控制网建设与似大地水准面精化

湖州市建设GPS基础控制网，实现了一个地区建立一个高精度、实时性、三维动态的大地控制基准，有效提高了测绘的管理水平和工作效率。本文就此作了论述。     

沉降曲线的绘制

本文介绍了绘制沉降曲线的方法，着重分析了程序设计的思路和过程，最后给出了一个程序实例。     

地理信息系统中的拓扑数据结构

本文以一个有代表性的图形文件为例，阐述了地理信息系统中的一个重要概念－拓扑关系，并说明如何关系数据表来描述和表达图素的拓扑关系，以及拓扑关系的应用。     

建议将测绘科学更名为地球信息学

本文简要谈了一个测绘科学更名的必要性，介绍了地球信息学的涵义，重点论述了测绘科学更名为地球信息学的理由。     

自适应Lp估计及其应用

本文详细介绍了自适应Ｌｐ估计的原理，计算方法和参数估值的性质，并给出了一个ＳＬＲ数据预处理的应用实例。     

建设"数字通州"总体构想

数字区域建设已在全国省级范围内取得重大进展，数字区域建设越来越受到广泛关注，本文以一个基层测绘管理工作者的眼光就一个县级市如何进行数字区域建设提出了总体构想。     

地理信息系统中几何特征不确定性的通用模型：从1维到N维

本文提出了描述地理信息系统中几何特征位置不确定性的一个通用模型，从１维到Ｎ维，在每１维中，ＧＩＳ中的特征被划分为点，线段及线性特征。由于ＧＩＳ中数据含有误差。这些特征在ＧＩＳ中位置未必与其现实世界中的真实位置一致，而其真实位置只是在围绕着ＧＩＳ中量测位置的某一个区域内，本文提出的模型给出了这些区域的统计描述。     

GIS空间数据的统计质量控制模型

本文讨论了一个用于分析ＧＩＳ中数据误差的简单统计模型，该模型还不是一项实用技术，只是今后长期研究的起点，以数字化过程为出发点建立了一个ＡＲＩＭＡ模型，并论述了必须利用完全的，可计算型的统计质量模型来分析问题的复杂性和范围。     

ANALYTICAL AERIAL TRIANGULATION BLOCK ADJUSTMENT; THE DIRECT HEIGHT SOLUTION INCORPORATING TIE-STRIPS

The historical development of analytical aerial triangulation block adjustment is mentioned by way of introduction. The advantages of separating the plan and height adjustments are given and the observation equations of a typical adjustment section are analysed to show that this convenient practice is justified in normal circumstances. The principles of a direct solution of the normal equations suitable for a moderate-sized computer, are explained and developed in detail for the height adjustment. The advantages of tie-strips in the height adjustment are demonstrated and the difficulties which then arise are discussed. An approximate method which overcomes these difficulties is developed. Details of the computer programmes used are given in Appendix B.     

基于单邻点多波段预测的高光谱图像无损压缩算法

提出了一种基于聚类-单邻点、多波段预测-熵编码的高光谱数据无损压缩方法。根据谱向特征,进行高光谱图像矢量聚类。对各个分类,采用单个空间位置邻点、多个波段作为预测数据,训练预测系数,进行三维预测。残差采用Golomb-Rice编码。实验证实了算法的有效性。     

基于两个独立抽样框架的农作物种植面积遥感估算方法

通过分析遥感技术在中国农作物种植面积估算中所遇到的难点 ,针对运行化的农作物遥感估产系统对主要农作物种植面积估算的需求 ,提出在农作物种植结构区划的基础上 ,采用整群抽样和样条采样技术相结合的方法 ,进行农作物种植面积估算。整群抽样技术利用遥感影像估算农作物总种植成数 ,样条采样是一种适合中国农作物种植结构特征的采样技术 ,用于调查不同农作物类别在所有播种作物中的分类成数。在中国现有的耕地数据库基础上 ,根据两次抽样获得的成数 ,计算得到具体某一种农作物类别的种植面积。最后给出了 2 0 0 3年早稻种植面积估算的实例。     

地籍宗地面积处理的原理与方法

探讨以地图数字化为基础的地理信息系统建库中地籍宗地数字化的面积处理问题,阐述宗地面积平差的原理,并导出了相应的条件方程,讨论宗地面积处理的各种和实现,提出宗地面积处理的分级平差方法;最后通过实例分析,认为宗地面积的平差处理有助于实现GIS数据采集和建库过程中实施质量控制,保证地理信息基础数据的质量可靠性,为系统的数据开发应用奠定基础。     

基于距离和姿态观测量的GNSS基线网平差方法

针对目前单历元算法需要连续观测较长时间才能够得到较为精确的解算结果的问题,利用载具同时架设3台GNSS接收机,获得基线观测量,同时事先精确测定接收机之间的距离,并利用陀螺仪获得载具的姿态角,通过增加距离和姿态观测量,与基线观测量共同进行平差处理,可以得到单历元较为稳定而精确的坐标解算结果。试验表明,平面精度在10 mm以内,高程精度在3 cm以内,相较于不添加距离和姿态观测量的结果精度提高了15%以上。     

Analytical versus semi-analytical determinations of the Oppolzer terms for a non-rigid Earth

Estimations of the Oppolzer terms for the angular momentum and rotation axes of a non-rigid Earth are obtained from two different approaches and compared. The first approach is an analytical method which relies on the solutions of the Liouville equations for a two-layer Earth model. The Oppolzer terms are evaluated from analytical expressions. The results are then compared to those calculated from Wahr's theory of nutation for a non-rigid Earth, which is the second approach used. Results are obtained for the main nutation frequencies and for the precession case. The differences between the two solutions are generally quite small (the relative error is most of the time under 8%) and are, for a large part, due to successive approximations and truncation effects during their determination. Departures of the results from the two methods are significantly larger for frequencies near the Free Core Nutation (FCN) resonance. This is particularly true for the Oppolzer terms of the angular momentum axis. The Earth model adopted is a little bit different in each case: for the Liouville system solution, we have limited the model to a homogeneous elastic mantle and a homogeneous liquid core. Another source of some of the small differences in the results is the presence of a solid inner core in Wahr's theory. We confirm through the analytical calculation the strong effect of the core on the Oppolzer terms of the angular momentum axis for a non-rigid Earth at the precession frequency. Finally, an application is given in the determination of the axes' position at J2000 for a non-rigid Earth. Received: 23 February 1998 /Accepted: 18 November 1998     

Determining Semantic Similarity of Behaviour Using Natural Semantic Metalanguage to Match User Objectives to Available Web Services

Natural Semantic Metalanguage specifies a set of semantic primitives identified by linguists since the 1970s as being present in all analysed languages and not capable of further reduction. In this article, the 63 semantic primitives are used to define the semantics of user objectives and web services in the form of semantic explications, which are then compared to determine whether the web services are likely to be helpful in meeting the user objective. The comparison of the user objectives and web services is a two stage process. Firstly, the content is compared by classifying the semantic primitives from the candidate web service and user objective on the basis of whether the primitives are common or similar. On the basis of these classifications, the percentage match and semantic relationship (subset, superset, overlaps, disjoint, identical) are determined. Secondly, the order of the semantic primitives is compared and the edit distance determined as a measure of semantic similarity. The method is tested using two examples: a comparison of spatial relations and a comparison of a user objective and three geospatial web services. The results show that the method is able to determine which concepts are broadly semantically similar and which are not.     

基于新闻中地名共现网络的中原城市群中尺度结构特征探测

本文以中原城市群为研究区,构建了新闻中地名共现网络,并搭建了探测城市网络社区结构和核心-边缘结构的方法框架。结果表明：①中原城市群被划分为5个社区,省级界线在虚拟网络空间城市的交互中起到了较大的阻碍作用;②在河南省城市所组成的核心-边缘结构中,核心城市围绕郑州呈斜"L"形分布;③中原城市群内郑州的中心地位较突出,洛阳的副中心地位不明显,整体多中心水平较低。基于以上结果,本文从区域规划、城市角色定位等方面给出了建议,对于中原城市群的一体化集成与发展有一定的促进作用。     

Kaiser filter for antialiasing in digital photogrammetry

Image aliasing is a problem appearing as artefacts in digitally resampled images, which degrades the quality of the image. In digital rectification and texture mapping, pixels from an input image are transformed to pixels of an output image. The discrete nature of a digital image causes aliasing in the transformed image. In this paper the source of aliasing and the theory of antialiasing are described. The necessity of a precise filter design in antialiasing is discussed and a filter based on a Kaiser adjustable window is designed. Different practical antialiasing methods are described as well as interpolation methods, which are conventional in photogrammetry. Selected antialiasing methods are implemented and applied to a close range image. An objective analysis is carried out by applying inverse transformations to rectified images and deriving some measures to estimate the information loss for each method by comparing original and reconstructed images. Results indicate that interpolation methods are not capable of removing or reducing aliasing in highly decimating transformations. The output images of interpolation methods therefore suffer from edge corruption and interfusion of small features. Applying a Kaiser filter with a precise antialiasing method results in the least information loss and considerably reduces aliasing at the expense of higher computation load.     

GIS中宗地面积的平差模型与方案探讨

首先给出了面积平差的基本原理和数学模型，并提出了面积平差处理的3种方案，并对这3种方案进行了实际计算和分析。