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231.
虚拟地形投影与地球同步卫星定位解全集 总被引:1,自引:0,他引:1
程芦颖 《武汉大学学报(信息科学版)》2005,30(7):629-631
基于地球同步卫星定位原理,分析了当利用数字化地形图提供测站高程时测站的多解和无解现象。利用观测方程给出了判断多解和无解的依据,提出了虚拟地形投影方法,获得了“亚稳定”收敛点的定位解子集π2。 相似文献
232.
Algebra, in particular commutative algebra, is applied here to provide a general unified solution to nonlinear systems of equations encountered in geodesy. Starting with the “Abelian group”, the “polynomial ring” is defined and used to form generators of ideals. By applying Buchberger or polynomial resultant algorithms, these generators are reduced to simple structures often comprising a univariate polynomial in one of the unknowns. The advantage of the proposed unified approach is that it provides exact solutions to geodetic nonlinear systems of equations without the traditional requirements of linearization, iterations or approximate starting values. The commutative algebraic approach therefore alleviates the need for isolated exact solutions to various geodetic nonlinear systems of equations. The procedure is applied to GPS meteorology to compute refraction angles, and Helmert’s one-to-one mapping of topographical points onto the reference ellipsoid. 相似文献
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234.
Amalgamation of parts of a composition has been extensively used as a technique of analysis to achieve reduced dimension,
as was discussed during the CoDaWork'03 meeting (Girona, Spain, 2003). It was shown to be a non-linear operation in the simplex that does not preserve distances
under perturbation. The discussion motivated the introduction in the present paper of concepts such as group of parts, balance
between groups, and sequential binary partition, which are intended to provide tools of compositional data analysis for dimension
reduction. Key concepts underlying this development are the established tools of subcomposition, coordinates in an orthogonal
basis of the simplex, balancing element and, in general, the Aitchison geometry in the simplex. Main new results are: a method
to analyze grouped parts of a compositional vector through the adequate coordinates in an ad hoc orthonormal basis; and the study of balances of groups of parts (inter-group analysis) as an orthogonal projection similar
to that used in standard subcompositional analysis (intra-group analysis). A simulated example compares results when testing
equal centers of two populations using amalgamated parts and balances; it shows that, in certain circumstances, results from
both analysis can disagree. 相似文献
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237.
矩阵运算的几种算法实现探讨 总被引:2,自引:0,他引:2
以求解正形变换10参数为例,讨论了分别采用True BASIC语言、Mathematica软件、MATLAB软件和C Builder语言的矩阵运算的算法实现方法,分析了4种算法的计算结果,说明了其相互之间精度相差很小、各有所长。 相似文献
238.
Environmental data are highly variable. They also include uncertainties resulting from all steps of the analytical process e. g. sampling, or sampling pre‐treatment. However, a lot of information is unfortunately often lost because only univariate statistical methods are used for data evaluation and interpretation. This neglects correlation between different pollutants and relationships among various sampling points. It is therefore necessary to apply additional methods of analysis that can accommodate such relationships. This ability is provided by the established, and by the more modern, multivariate statistical methods because they can analyze complex sets of multidimensional data. These methods are used to visualize large amounts of data and to extract latent information (e. g. differently polluted areas, dischargers, or interactions between different environmental compartments). The goal of this paper is to present the use of established statistical techniques, like cluster or factor analysis, and the progress made in basic modern techniques (e. g. cluster imaging, multiway‐partial least squares regression, projection pursuit, or information theory) and to demonstrate each with examples and illustrations. 相似文献
239.
本文首先介绍航空摄影测量数字相机相对于传统的胶片相机所具有的优点,然后重点分析了市场上最新流行的两种大面阵航空摄影测量数字相机的等效中心投影像片的形成方法及其测量精度。实验分析表明:航空摄影测量数字相机系统用于平坦地区作业时能获得较高的精度,但用于山区作业时,作业精度明显下降,因此在地形起伏较大的地区,若作业精度要求较高,则应谨慎使用这两种数字相机。 相似文献
240.