共查询到20条相似文献，搜索用时 15 毫秒
1.
《The Cartographic journal》2013,50(1):9-14
AbstractThe use of the aerial photograph as a basis for a topographic map is currently one of the most interesting developments in cartography. A member of the staff of the Army Map Service, who is primarily concerned with investigations into map design, presents some possible lines of development in this field. 相似文献
2.
《测量评论》2013,45(8):105-108
AbstractAs air-photographs are being more and more used for survey purposes, Empire surveyors who have not yet made a thorough study of aerial survey may be interested in a little elementary photographic geometry and its application to map-making. A map may be described as an orthogonal proj ection of the ground upon a horizontal plane, reduced to some convenient scale, and a photograph as a conical projection of the ground upon the focal plane of the camera. If the focal plane is horizontal at the instant of exposure and the ground being photographed is perfectly level, the two projections are exactly similar and the photograph is indeed a map. Unfortunately these conditions which are illustrated in fig. 1 are extremely rarely encountered, and photographs usually need correcting for various distortions. 相似文献
3.
《测量评论》2013,45(81):138-140
Abstract1. In a paper on “Some Recent Developments in Photogrammetry” which he read recently at the Royal Institution of Chartered Surveyors and which has now been published in the Institution's Journal, Lieut.-Col. E. H. Thompson, R.E., expounded the advantages of using a reseau ruled on the glass pressure plate of the camera in order to obtain a calibrated grid on each photograph. 相似文献
4.
《The Cartographic journal》2013,50(2):121-126
AbstractIn order to display, predict and combat atmospheric pollution, suitable graphics should be employed. The author proposes some new methods of representation such as mapping air pollution on an air photograph which is printed through screens proportional to air purity, or using the Polyfocal Projection for mapping airport noise. Polar diagrams are used to depict atmospheric stability states. 相似文献
5.
《测量评论》2013,45(73):131-137
AbstractMany have tried their hands at one time or another at developing practical methods in respect to the solutions of the four fundamental problems viz., (1) space resection, (2) orientation of photograph in space and relative to one another, (3) space intersection, and (4) photogrammetric extension of surveys without ground control. The trouble so far has been that each worker had his own particular problem to solve and hence a completely general and comprehensive approach to the problems is lacking. In this paper these four fundamental problems are considered as essentially one of a system of linear transformations, from one set of coordinates to another, bearing in mind the existence of the significant correspondence between pairs of image points and points in space. 相似文献
6.
This study presents a model of a color photograph as a transparent medium with particles of colored pigment embedded in it, with the characteristics of the pigment determining the hue of the picture, and the pigment concentration determining the purity of the color. On the basis of this proposed model, the study undertakes a theoretical examination of an automated method for determining the parameters of a color photograph (the hue and purity) based on scanning the picture with white light and analyzing the output signals of two photodetectors placed behind the photograph in question. Analytical formulae are derived which can be used to measure the color characteristics of a color photograph using the output signals of the photodetectors which, in turn, allows these measurements to be made automatically with simple equipment. Translated from: Izvestiya vuzov, Geodeziya i aerofoto-s'yemka, 1984, No. 2, pp. 65-70. 相似文献
7.
On the multivariate total least-squares approach to empirical coordinate transformations. Three algorithms 总被引：2，自引：1，他引：1
The multivariate total least-squares (MTLS) approach aims at estimating a matrix of parameters, Ξ, from a linear model (Y−E
Y
= (X−E
X
) · Ξ) that includes an observation matrix, Y, another observation matrix, X, and matrices of randomly distributed errors, E
Y
and E
X
. Two special cases of the MTLS approach include the standard multivariate least-squares approach where only the observation
matrix, Y, is perturbed by random errors and, on the other hand, the data least-squares approach where only the coefficient matrix
X is affected by random errors. In a previous contribution, the authors derived an iterative algorithm to solve the MTLS problem
by using the nonlinear Euler–Lagrange conditions. In this contribution, new lemmas are developed to analyze the iterative
algorithm, modify it, and compare it with a new ‘closed form’ solution that is based on the singular-value decomposition.
For an application, the total least-squares approach is used to estimate the affine transformation parameters that convert
cadastral data from the old to the new Israeli datum. Technical aspects of this approach, such as scaling the data and fixing
the columns in the coefficient matrix are investigated. This case study illuminates the issue of “symmetry” in the treatment
of two sets of coordinates for identical point fields, a topic that had already been emphasized by Teunissen (1989, Festschrift
to Torben Krarup, Geodetic Institute Bull no. 58, Copenhagen, Denmark, pp 335–342). The differences between the standard least-squares
and the TLS approach are analyzed in terms of the estimated variance component and a first-order approximation of the dispersion
matrix of the estimated parameters. 相似文献
8.
R. H. Rapp 《Journal of Geodesy》1969,43(1):47-80
A set of2261 5°×5° mean anomalies were used alone and with satellite determined harmonic coefficients of the Smithsonian' Institution to determine
the geopotential expansion to various degrees. The basic adjustment was carried out by comparing a terrestrial anomaly to
an anomaly determined from an assumed set of coefficients. The (14, 14) solution was found to agree within ±3 m of a detailed geoid in the United States computed using1°×1° anomalies for an inner area and satellite determined anomalies in an outer area. Additional comparisons were made to the
input anomaly field to consider the accuracy of various harmonic coefficient solutions.
A by-product of this investigation was a new γE=978.0463 gals in the Potsdam system or978.0326 gals in an absolute system if −13.7 mgals is taken as the Potsdam correction. Combining this value of γE withf=1/298.25, KM=3.9860122·10
22
cm
3
/sec
2
, the consistent equatorial radius was found to be6378143 m. 相似文献
9.
Y. Kozai 《Journal of Geodesy》1968,42(3):355-357
From periodic variations of the orbital inclinations of three artificial satellites 1959Alpha 1, 1960Iota 2, and 1962Beta Mu 1 Love’s number of the earth and time lag of the bodily tide due to the friction are determined, respectively,0.29±0.03 and(10±5) minutes in time.
While the previous paper on the determination of Love’s number of the earth (Kozai, 1967) was in press, a minor error was
discovered in the Differential Orbit Improvement program(DOI) of the Smithsonian Astrophysical Observatory(SAO). Since the analysis was based on time-variations of the orbital inclinations which were derived by theDOI from precisely reduced Baker-Nunn observations, it is likely that the results in the previous paper was affected by the error
in theDOI. Therefore, the analysis is iterated by using the revisedDOI. Three satellites, 1959Alpha 1 (Vanguard 2), 1960Iota 2 (rocket ofEcho 1), and 1962Beta Mu 1 (Anna) (see Table 1) are adopted for determining Love’s number in the present paper. The satellite, 1959Eta, which was used in the previous paper, is not adopted here, since the inclination of this satellite shows irregular variations
unexplained. Instead of 1959Eta 1962Beta Mu 1 is adopted as orbital elements from precisely reduced Baker-Nunn observations have become available for a long interval of
time for this satellite. 相似文献
10.
《测量评论》2013,45(94):372-376
AbstractIn the October 1953 issue of this Review (E.S.R. xii, 90, 174), Mr. J. G. Freislich has written of the difficulties of a southern hemisphere computer attempting to use astronomical formulae from a textbook prepared for use in the northern hemisphere. He proposes a solution in which different conventions are adopted in the two hemispheres, leading to different formulae for the two cases, a solution which the present writer does not favour. 相似文献
11.
An investigation was made of the behaviour of the variable
(where ρij are the discrepancies between the direct and reverse measurements of the height of consecutive bench marks and theR
ij
are their distance apart) in a partial net of the Italian high precision levelling of a total length of about1.400 km.
The methods of analysis employed were in general non-parametric individual and cumulative tests; in particular randomness,
normality and asymmetry tests were carried out. The computers employed wereIBM/7094/7040. From the results evidence was obtained of the existence of an asymmetry in respect to zero of thex
ij
confirming the well-known results given firstly by Lallemand. A new result was obtained from the tests of randomness which
put in evidence trends of the mean values of thex
ij
and explained some anomalous behaviours of the cumulative discrepancy curves. The extension of this investigation to a broader
net possibly covering other national nets would be very useful to get a deeper insight into the behaviour of the errors in
high precision levelling. Ad hoc programs for electronic computers are available to accomplish this job quickly.
Presented at the 14th International Assembly of Geodesy (Lucerne, 1967). 相似文献
12.
In the field of biomass estimation, terrain radiometric calibration of airborne polarimetric SAR data for forested areas is an urgent problem. Illuminated area correction of σ -naught could not completely remove terrain features. Inspired by Small and Shimada, this paper tested gamma-naught on one mountainous forested area using airborne Uninhabited Aerial Vehicle Synthetic Aperture Radar data and found it could remove most terrain features. However, a systematic increasing trend from far range to near range is found in airborne SAR cases. This paper made an attempt to use the relationship between distance to SAR sensor and γ-naught to calibrate γ -naught. Two quantitative evaluation methods are proposed. Experimental results demonstrate that variation of γ -naught can be constrained to a limited extent from near range to far range. Since this method is based on ground range images, it avoids complicated orthorectification. 相似文献
13.
数字航空影像辐射信息精处理问题的探讨 总被引：1，自引：0，他引：1
在分析数字航空影像辐射信息的基础上,针对数字航空像片的特点,探讨对数字航空影像进行匀光和匀色处理的技术方法,以及实现批量化处理的方法研究。 相似文献
14.
本文所述方法的基本思路是：根据空间后方交会原理建立单张航片的投影变换模型，利用扫描仪输入航片调绘数据和地形高程数据，利用投影变换模型对航片数据进行变换处理，从而实现对航片的转绘。该方法适用于高山、丘陵、平地的航片转绘。 相似文献
15.
E. Mittermayer 《Journal of Geodesy》1972,46(2):139-157
Summary The system of normal equations for the adjustment of a free network is a singular one. Therefore, a number of coordinates
has to be fixed according to the matrix. The mean square errors and the error ellipses of such an adjustment are dependent
on this choice.
This paper gives a simple, direct method for the adjustment of free networks, where no coordinates need to be fixed. This
is done by minimizing not only the sum of the squares of the weighted errorsV
T
PV=minimun but also the Euclidean norm of the vectorX and of the covariance matrixQ X
T
X=minimum trace (Q)=minimum This last condition is crucial for geodetic problems of this type. 相似文献
16.
17.
The twin perspective 4 point (twin P4P) problem – also called the combined three dimensional resection-intersection problem – is the problem of finding
the position of a scene object from 4 correspondence points and a scene stereopair. While the perspective centers of the left and right scene image are positioned by means of a double three dimensional resection, the position of the scene object imaged on the left and right photograph is determined by a three dimensional intersection based upon given resected perspective centers. Here we present a new algorithm solving the twin P4P problem by means of M?bius barycentric coordinates. In the first algorithmic step we determine the distances between the perspective centers and the unknown intersected point by solving a linear system of
equations. Typically, area elements of the left and right image build up the linear equation system. The second algorithmic step allows for the computation of the M?bius barycentric coordinates of the unknown intersected point which are thirdly converted into three dimensional object space coordinates {X,Y,Z} of the intersected point. Typically, this three-step algorithm based upon M?bius barycentric coordinates takes advantage of the primary double resection problem from which only distances from four correspondence points to the left and right perspective centre are needed. No orientation parameters and no coordinates
of the left and right perspective center have to be made available.
Received 1 May 1996; Accepted 13 September 1996 相似文献
18.
Gravity observations from superconducting gravimeters are used to observe loading effects from shallow-water tides on the Japanese east and west coasts. Non-linear third-diurnal and higher-frequency shallow-water tides are identified in the tide-gauge observations from these coastal areas. The most energetic constituents in the tide gauge observations are also seen in the gravity observations due to their loading effects on the deformation of the Earth. Even though the shallow-water tides at the Japanese east coast have an amplitude of only a few millimetres, they are still able to generate a loading signal at gravity sites located several hundred kilometres inland. In particular, the S3, S4 and S5 solar tides occur in both gravity and tide gauge observations. It is indicated that in other shelf regions with large shallow water tides, the shallow water loading signals account for a significant signal, which should be taken into account.Acknowledgement The authors would like to thank the Hydrographic and Oceanographic Department (Japan Coast Guard), Japan Meteorological Agency and Hokkaido Development Agency for access to the tide-gauge data. Also, the Global Geodynamic Project Information System and Data Center (GGP-ISDC) is acknowledged for providing the gravity data. 相似文献
19.
Mixed Integer-Real Valued Adjustment (IRA) Problems: GPS Initial Cycle Ambiguity Resolution by Means of the LLL Algorithm 总被引：4，自引：0，他引：4
Erik W. Grafarend 《GPS Solutions》2000,4(2):31-44
In order to achieve to GPS solutions of first-order accuracy and integrity, carrier phase observations as well as pseudorange
observations have to be adjusted with respect to a linear/linearized model. Here the problem of mixed integer-real valued
parameter adjustment (IRA) is met. Indeed, integer cycle ambiguity unknowns have to be estimated and tested. At first we review
the three concepts to deal with IRA: (i) DDD or triple difference observations are produced by a properly chosen difference
operator and choice of basis, namely being free of integer-valued unknowns (ii) The real-valued unknown parameters are eliminated
by a Gauss elimination step while the remaining integer-valued unknown parameters (initial cycle ambiguities) are determined
by Quadratic Programming and (iii) a RA substitute model is firstly implemented (real-valued estimates of initial cycle ambiguities)
and secondly a minimum distance map is designed which operates on the real-valued approximation of integers with respect to
the integer data in a lattice. This is the place where the integer Gram-Schmidt orthogonalization by means of the LLL algorithm (modified LLL algorithm) is applied being illustrated by four examples. In particular, we prove
that in general it is impossible to transform an oblique base of a lattice to an orthogonal base by Gram-Schmidt orthogonalization where its matrix enties are integer. The volume preserving Gram-Schmidt orthogonalization operator constraint to integer entries produces “almost orthogonal” bases which, in turn, can be used to produce the integer-valued
unknown parameters (initial cycle ambiguities) from the LLL algorithm (modified LLL algorithm). Systematic errors generated
by “almost orthogonal” lattice bases are quantified by A. K. Lenstra et al. (1982) as well as M. Pohst (1987). The solution point of Integer Least Squares generated by the LLL algorithm is = (L')−1[L'◯] ∈ ℤ
m
where L is the lower triangular Gram-Schmidt matrix rounded to nearest integers, [L], and = [L'◯] are the nearest integers of L'◯, ◯ being the real valued approximation of z ∈ ℤ
m
, the m-dimensional lattice space Λ. Indeed due to “almost orthogonality” of the integer Gram-Schmidt procedure, the solution point is only suboptimal, only close to “least squares.” ? 2000 John Wiley & Sons, Inc. 相似文献
20.
In satellite data analysis, one big advantage of analytical orbit integration, which cannot be overestimated, is missed in
the numerical integration approach: spectral analysis or the lumped coefficient concept may be used not only to design efficient
algorithms but overall for much better insight into the force-field determination problem. The lumped coefficient concept,
considered from a practical point of view, consists of the separation of the observation equation matrix A=BT into the product of two matrices. The matrix T is a very sparse matrix separating into small block-diagonal matrices connecting the harmonic coefficients with the lumped
coefficients. The lumped coefficients are nothing other than the amplitudes of trigonometric functions depending on three
angular orbital variables; therefore, the matrix N=B
T
B will become for a sufficient length of a data set a diagonal dominant matrix, in the case of an unlimited data string length
a strictly diagonal one. Using an analytical solution of high order, the non-linear observation equations for low–low SST range data can be transformed into a form to allow the application of the lumped concept.
They are presented here for a second-order solution together with an outline of how to proceed with data analysis in the spectral
domain in such a case. The dynamic model presented here provides not only a practical algorithm for the parameter determination
but also a simple method for an investigation of some fundamental questions, such as the determination of the range of the
subset of geopotential coefficients which can be properly determined by means of SST techniques or the definition of an optimal
orbital configuration for particular SST missions. Numerical results have already been obtained and will be published elsewhere.
Received: 15 January 1999 / Accepted: 30 November 1999 相似文献