摘要:

AbstractKnow…That on the summit whither thou art bound A geographic Labourer pitched his tent, With books supplied and instruments of art, To measure height and distance; lonely task, Week after week pursued!Wordsworth, 1813, from‘Written with a slate pencil on a stone on the side of the Mountain of Black Comb’.

ISSN:0039-6265    

DOI:10.1179/sre.1991.31.241.126

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

AbstractFormulae to calculate the gravity effect due to 1°averaged topographic heights or depths on the idealised earth, are duly modified to apply to the reduction of corresponding topographic-isostatic effects on the Airy-Heiskanen hypothesis for any normal thickness Toof the earth's crust.Topographic-isostatic effects are calculated using electronic computers, for the entire earth, that is, for the Hayford zones A to I at the mean positions of l°×1°squares of latitudes and longitudes and then added to the given l°×1°mean free-air gravity anomaly-values computed at the identical positions in order to obtain the required Airy isostatic gravity anomalies for any normal thickness of the earth's crust.

ISSN:0039-6265    

DOI:10.1179/sre.1991.31.241.148

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

AbstractComplete equations (showing general terms) are derived for the spherical isocurve, and the differences for the spheroidal isocurve indicated. The suitability of various equations for different latitude zones is examined.

ISSN:0039-6265    

DOI:10.1179/sre.1991.31.241.159

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

AbstractThe attempt to divide a random angle into three precisely equal parts using only compasses and straightedge and complying rigidly with the rules of Euclidean geometry has always eluded mathematicians and was finally proven impossible by P. L. Wantzel in 1847. This paper demonstrates a simple construction using only compasses and straightedge which achieves an extremely accurate trisection and questions the significance of Wantzel's proof.

ISSN:0039-6265    

DOI:10.1179/sre.1991.31.241.167

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

AbstractThe shape of the geoid in Africa is determined using Transit satellite observation of the African Doppler Survey (A.DO.S) project. Results show that the geoid in Africa is rising from the Red Sea coast to the north-west direction, and from Somalian coast to the south-west direction relative to both the NWL-9D and Geodetic Reference System 1980 (GRS80) ellipsoids. Comparison of the geoid solution in this study with other available geoid solutions, show a general agreement to a few metres.

ISSN:0039-6265    

DOI:10.1179/sre.1991.31.241.175

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

ISSN:0039-6265    

DOI:10.1179/sre.1991.31.241.181

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

ISSN:0039-6265    

DOI:10.1179/sre.1991.31.241.182

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

ISSN:0039-6265    

DOI:10.1179/sre.1991.31.241.183

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

ISSN:0039-6265    

DOI:10.1179/sre.1991.31.241.184

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

ISSN:0039-6265    

DOI:10.1179/sre.1991.31.241.185

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor