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1.
《测量评论》2013,45(27):267-269
AbstractAfter the completion of Simms's Geodetic Chain in 1901 and the publication of the results in 1905—Volume iii of the Geodetic Survey of South Africa—nothing further of a geodetic nature was done until 1928 when a short chain was run westwards from Simms's chain, at about latitude 17° 10′, to fix the Copper Queen mining area. The Eastern Circuit was commenced shortly after this; it runs from Salisbury eastwards to the Portuguese Boundary, southwards through Umtali to about latitude 20° and then westwards, joining Simms's chain again to the east of Bulawayo. Another chain running north from Simms's work has been commenced near Bulawayo. The several series are exhibited on the outline map attached. 相似文献
2.
《测量评论》2013,45(35):275-279
Abstract Triangulation.—Apart from Simms' Geodetic Chain, Gordon's Chain, the Copper Queen Limb, and a section of the Victoria and Umtali Series, all the primary triangulation shown on the accompanying map has been executed since 1933. The work of Simms and Gordon has been remodelled, however, being greatly strengthened, and these chains are now called Simms' and Gordon's Series. For an explanation and plan of the above Series, see “A Note on the Trigonometrical Survey of S. Rhodesia”, in the Empire Survey Review, no. 27, vol. iv. 相似文献
3.
《测量评论》2013,45(48):50-56
AbstractIn the memoir of the late Capt. G. T. McCaw which appeared in the January number of this Review (vii, 47,2), reference was made to the part which the late Sir David Gill played in the origin of the work on the survey of the Arc of the 30th Meridian in Africa. This year is the centenary of Gill's birth, as he was born in June 1843, and it is therefore timely to give some account of his work during his long term of office as Her Majesty's Astronomer at the Cape which resulted inthe inception and completion of the Geodetic Survey of South Africa and the survey of the Arc to the southern shores of Lake Tanganyika. He died on 24th January 1914. 相似文献
4.
《测量评论》2013,45(65):131-134
Abstract1. In geodetic work a ‘Laplace Point’ connotes a place where both longitude and azimuth have been observed astronomically. Geodetic surveys emanate from an “origin” O, whose coordinates are derived from astronomical observations: and positions of any other points embraced by the survey can be calculated on the basis of an assumed figure of reference which in practice is a spheroid formed by the revolution of an ellipse about its minor axis. The coordinates (latitude = ?, longitude = λ and azimuth = A) so computed are designated “geodetic”. 相似文献
5.
6.
《测量评论》2013,45(45):393-401
AbstractThe first instrument of the new design of the Geodetic Tavistock theodolite was received by the Geodetic Service of Canada early in 1939. It has now been well tried out both in field and laboratory, and a few minor changes have been accepted by the manufacturer. The reactions of field men and the results of laboratory tests may be of interest. 相似文献
7.
《测量评论》2013,45(77):302-306
AbstractAlthough during World War II field work on geodetic subjects other than those directly connected with the war effort remained practically in abeyance, the war provided unique opportunities for the study and execution of several interesting problems such as the linking of Indian triangulation with Iraq and Iran on the one hand and Siam and Malaya on the other. A detailed account of the Geodetic work of the Survey of India during the period 1939-47 is given in the Survey of India “Technical Report 1947—Part III, Geodetic Work”. 相似文献
8.
《测量评论》2013,45(17):130-131
AbstractFollowing a request from the Commission of Government of Newfoundland, the Canadian Government has consented to an arrangement whereby the Geodetic Survey of the Department of the Interior will assist the Island Government in laying down two main nets of triangulation as the basis for the survey development of Newfoundland. The completion of the final practical details was reached in Ottawa recently, and the work, it is expected, will extend over a period of five years. 相似文献
9.
A new adjustment of the geodetic control networks in North America has been completed, resulting in a new continental datum—the
North American Datum of 1983 (NAD 83).
The establishment ofNAD 83 was the result of an international project involving the National Geodetic Survey of the United States, the Geodetic Survey
of Canada, and the Danish Geodetic Institute (responsible for surveying in Greenland). The geodetic data in Mexico and Central
America were collected by the Inter American Geodetic Survey and validated by the Defense Mapping Agency Hydrographic/Topographic
Center.
The fundamental task ofNAD 83 was a simultaneous least squares adjustment involving 266,436 stations in the United States, Canada, Mexico, and Central
America. The networks in Greenland, Hawaii, and the Caribbean islands were connected to the datum through Doppler satellite
and Very Long Baseline Interferometry (VLBI) observations.
The computations were performed with respect to the ellipsoid of the Geodetic Reference System of 1980. The ellipsoid is positioned
in such a way as to be geocentric, and its axes are oriented by the Bureau International de l'Heure Terrestrial System of
1984.
The mathematical model for theNAD readjustment was the height-controlled three-dimensional system. The least squares adjustment involved 1,785,772 observations
and 928,735 unknowns. The formation and solution of the normal equations were carried out according to the Helmert block method.
[Authors' note:This article is a condensation of the final report of the NAD 83 project. The full report (Schwarz,1989) contains a more complete discussion of all the topics.] 相似文献
10.
《测量评论》2013,45(91):210-217
AbstractThe Wankie Geodetic Base was measured in May 1953 and the re-measurement of the Sabi Geodetic Base was also completed during the month following. For these measurements the standard “Macca” equipment was used, the gear being lent to the Southern Rhodesia Government by the Directorate of Colonial Surveys. As it was anticipated that both measurements would be made under hotter and more sunny conditions than normally prevail in England, the Directorate of Colonial Surveys suggested that the opportunity be taken of carrying out further tests in the determination of temperatures by the “resistance thermometer” as described by Messrs. Clark and Johnson of the National Physical Laboratory in their paper on the “Measurement of Temperature of Geodetic Surveying Tapes. Accordingly, through the good officesof the Director of the National Physical Laboratory, the apparatus comprising the resistance theremometer was made available for use on these two base measurements. 相似文献
11.
《测量评论》2013,45(82):159-163
AbstractThis project, which is now well known to surveyors not only in Africa but all over the world, was first visualised by Sir David Gill, who for many years was H.M. Astronomer at the Cape Observatory. It is fitting to commence by giving in his own words his conception of the work, the part of which from South Africa to the Equator has now been completed. The following extracts are taken from the paper “On the Origin and Progress of Geodetic Survey in South Africa, and of the African Arc of Meridian”, by Sir David Gill,K.C.B., F.R.S. 相似文献
12.
《测量评论》2013,45(43):258-269
AbstractWork on the original Geodetic Tavistock Theodolite was commenced in the autumn of 1931, and after suitable tests this instrument was sent out to East Africa and used on the East African Arc. Bt Major M. Hotine, R.E., writing in the E.S.R. of April 1935 (no. 16, vol. iii), stated: “The Tavistock instrument, although a first model, gave uniformly satisfactory service throughout and was used for over half the main angular observations.” 相似文献
13.
《测量评论》2013,45(54):311-314
AbstractThere has always been a marked difference of opinion on the relative merits of the methods of bearings and of angles as applied to triangulation, though it is probable that the majority of writers prefer the method of bearings for first-order work. The subject was mentioned in a recent issue of this Review (vii, 47, 19). 相似文献
14.
《测量评论》2013,45(74):146-155
AbstractShortly after the inception of the Geodetic Survey of Canada in 1905, reconnaissance for primary triangulation was commenced in the Ottawa-Montreal area. About the same time, precise levelliilg operations were begun from a bench mark already established by the United States Coast and Geodetic Survey near the International border at Rouses Point in Quebec. 相似文献
15.
《测量评论》2013,45(30):457-462
AbstractIn the original geodetic series in Southern Rhodesia—completed by Mr Alexander Simms in 1901—the geographical coordinates of all stations were referred to the point SALISBURYas origin. The coordinates of SALISBURY were fixed by interchange of telegraphic signals with the Royal Observatory at the Cape for longitude, combined with astronomical determinations of time, latitude, and azimuth (see Vol. III, “Geodetic Survey of South Africa”). 相似文献
16.
《测量评论》2013,45(29):430-437
AbstractThe Secondary Triangulation of South Africa consists of a uniform network of triangles of from 5- to 10-mile sides, enmeshed in the Geodetic and Primary Triangulations. As a rule the Primary Triangulation is rigorously adjusted by least squares, and the Secondary made to conform to it by an approximately rigorous method which was introduced into the Trigonometrical Survey in 1920 by the late Dr van der Sterr. 相似文献
17.
《The Cartographic journal》2013,50(1):97-110
AbstractIn July 2005 UNESCO voted to have the Struve Geodetic Arc inscribed on its List of World Heritage Monuments. Not only is this a first for the Surveying profession, but also for UNESCO in the sense of the type of monument it lists. This paper will outline the background to Arc measurement, give some details of the Struve Arc and its possible extension into Africa and indicate why it is not for the faint hearted to get involved in putting a monument of any sort up for UNESCO listing. 相似文献
18.
《测量评论》2013,45(53):266-271
AbstractSince 1929 much of the primary triangulation carried out by the Geodetic Service of Canada has been preceded by an aerial reconnaissance of the areas: during this reconnaissance a tentative selection is made of station sites, and likely lines of sight are indicated. Varied types of topography have been covered—mountainous, rolling, flat wooded, mountain valleys. In most cases there were three common factors: the areas were well watered with lakes and rivers which permitted low flying in safety with pontoonor skii-equipped planes, ground transportation was difficult, and no contour maps existed. In some of the areas existing maps were very incomplete; of a few, reconnaissance aerial maps were available in which the planimetry was good; the better the map the easier the aerial reconnaissance. In all cases it was considered necessary that the air operations be checked by ground visits to the tentatively selected stations. 相似文献
19.
《测量评论》2013,45(66):148-157
AbstractBefore concluding the discussion of longitudes, a few notes have been collected to illustrate the kind of discordance which can be found in longitude determinations of a higher class than those reviewed above. In the 1926 World Determination of Longitudes, the U.S. Coast and Geodetic Survey parties at Niu, near Honolulu, made observations which disclose some ranges in derived longitudes which may be regarded as representative. 相似文献
20.