ISSN:0039-6265    

DOI:10.1179/sre.1981.26.202.160

出版商:Taylor&Francis    

年代:1981

数据来源: Taylor

摘要:

AbstractGeoid maps of the British Isles have been constructed by several methods, and for a number of different geodetic datums. Datum shifts between a TRANSIT Doppler precise ephemeris co-ordinate system and OSGB 1970 and ED 1950 are also derived.

ISSN:0039-6265    

DOI:10.1179/sre.1981.26.202.161

出版商:Taylor&Francis    

年代:1981

数据来源: Taylor

摘要:

AbstractThe angle observations at a triangulation station are usually not made all around the same date. Sometimes, especially when a new adjustment of the triangulation is undertaken, it is found that the rounds of observations from different dates contain different combinations of directions and were measured with varying accuracy. There is no special difficulty to find the adjusted directions but in these cases the adjusted directions are usually correlated and it is not so easy to find the covariance matrix. The unknowns are the adjusted directions and the orientation of the zeros of the observation sets, but as is well known one of these unknowns is superfluous, making the matrix of normal equations singular. The best way to avoid this is to choose the value of one of the adjusted directions as zero. The choice of the zero direction does not affect the differences between the adjusted directions but has considerable influence on the covariance matrix. This matrix is used in the final adjustment of the triangulation station coordinates and therefore it must be independent of an arbitrary choice. Consequently the generalisation of the least squares adjustment method is necessary.

ISSN:0039-6265    

DOI:10.1179/sre.1981.26.202.180

出版商:Taylor&Francis    

年代:1981

数据来源: Taylor

ISSN:0039-6265    

DOI:10.1179/sre.1981.26.202.191

出版商:Taylor&Francis    

年代:1981

数据来源: Taylor

摘要:

AbstractTo transform plane coordinates (x,y) to their geodetic equivalents (ϕ,λ) the latter are expressed as functions of the“foot-point”latitudeϕ1. Although standard tables are available for these computations, the availability of computers in many survey offices has resulted in the need to employ new methods.In this paper an iterative method of computing the“foot-point”latitude is given The equation converges so fast that two or three iterations result in differences of less than 0.001 seconds of arc between two successive values.

ISSN:0039-6265    

DOI:10.1179/sre.1981.26.202.192

出版商:Taylor&Francis    

年代:1981

数据来源: Taylor

ISSN:0039-6265    

DOI:10.1179/sre.1981.26.202.194

出版商:Taylor&Francis    

年代:1981

数据来源: Taylor

摘要:

AbstractThis paper on theSURVEY REVIEWis based on the one presented to the 1971 Commonwealth Survey Conference, since there seemed little point in doing the research into its origins and early history all over again. The circulation of that paper was limited to a few hundred copies of the Proceedings so it will do no harm, and the management of the Conference has agreed to much of it being quoted here. I have brought it up to date till my retirement in 1977, and those now in charge have agreed to tell us how it is faring now.

ISSN:0039-6265    

DOI:10.1179/sre.1981.26.202.195

出版商:Taylor&Francis    

年代:1981

数据来源: Taylor

ISSN:0039-6265    

DOI:10.1179/sre.1981.26.202.201

出版商:Taylor&Francis    

年代:1981

数据来源: Taylor

ISSN:0039-6265    

DOI:10.1179/sre.1981.26.202.202

出版商:Taylor&Francis    

年代:1981

数据来源: Taylor

ISSN:0039-6265    

DOI:10.1179/sre.1981.26.202.203

出版商:Taylor&Francis    

年代:1981

数据来源: Taylor