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1.
《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
2.
《测量评论》2013,45(2):84-86
AbstractIn 1924, when my application for a position in the Survey Department of North Borneo had been accepted, a surprisingly large number of my friends thought that my destination was somewhere in Africa or South or Central America. Of course everyone had heard of the “wild man of Borneo.” To be quite candid, my own knowledge was limited to the position of the island. As this. country seems to be so little known, a brief outline of its history and of the development of the Survey Department may be of interest. 相似文献
3.
《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
4.
《测量评论》2013,45(16):72-80
AbstractIt was suggested some time ago in the Review (E.S.R., vol. ii, no. 9, p. 182) that observing procedure in a ruling triangulation should be made the subject of a discussion at the forthcoming Empire Survey Conference. I hope it will be. We shall perhaps learn why India finds thirty measures necessary, as no doubt they are necessary in India, whereas South Africa and Southern Rhodesia are able to secure much the same degree of accuracy from the same instrument with only eight; why Canada, again with the same instrument, prefers the golden mean of sixteen; why some of us still prefer the measurement of angles to directions vvhile others would insist entirely on the measurement of directions from a “close” R.O. It is only by pooling the experiences gained in diverse circumstances that we can avoid being overborne by our own successes or failures, encountered possibly in very exceptional circumstances which may not recur. 相似文献
5.
《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
6.
《测量评论》2013,45(91):222-226
AbstractThis discussion relates to the use by the Trigonometrical Survey of South Africa of Wild photogrammetric equipment in the compilation of 1/18,000 topographical maps from 1/30,000 photographs and to the accuracy of the work found thus far by field check. The equipment used, the field and compilation methods and the specifications for the work are briefly described in this article. 相似文献
7.
《测量评论》2013,45(76):255-260
AbstractWhilst turning over some old papers the other day I came across a copy of the first Annual Report of the Colonial Survey Committee, and the recent, much regretted death of Sir Herbert Read reminded me of his services in the development of the surveys and explorations of British possessions in Africa, especially his suggestion, which was approved by the Secretary of State for the Colonies, of the formation of the Colonial Survey Committee, an Advisory Committee which was set up in August, 1905. This Committee advised the Secretary of State “in matters affecting the survey and exploration of British Colonies and Protectorates, more especially those in Tropical Africa”. 相似文献
8.
《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
9.
《测量评论》2013,45(50):162-164
AbstractWhen I took over the command of a West Africa Brigade Group in 1939, I found that one of the units in the brigade was a survey section, and, in the course of training this brigade, I was rather concerned as to how this survey unit would or should be used. It was a small unit consisting of three officers (Europeans) and approximately 50 African other ranks, all belonging to the local Government Survey Department. I knew that it could map any particular piece of country, or could lay outbuilding sites, ranges, etc., but, beyond this, and normal military training, I am afraid that I could think of no other ways of using it. I knew also that, when the brigade was trained, we were to move to another part of Africa and that operations were likely to take place over country which was mostly unmapped. This, then, would be the opportunity for the survey section. At the same time, the size of the country we were likely to operate in was so enormous that my little survey unit would be swamped and quite unable to produce operational maps in time for me to use them. In due course we arrived on the scene of operations. My survey section was taken away from me and merged with other sections in a survey company. This company commenced to map parts of the country in which it was considered likely fighting might take place. This was exactly what I had anticipated, although I still considered that even this bigger unit was much too small for the huge job it had to do. 相似文献
10.
《The Cartographic journal》2013,50(3):237-248
AbstractSince 1906, South Africa boasted an excellent geodetic framework, and in 1920 an official Trigonometrical Survey Office (TSO) was established. In spite of these achievements, the country, by the 1930s, still lacked reliable topographical maps. One reason for this was that the secondary and tertiary triangulations of the country were still incomplete; another was that the decision-making process as regards surveys and mapping rested with a variety of statutory bodies instead of just one. In 1934, A. D. Lewis, Director of the Department of Irrigation, committed his department to execute a general topographical survey of the country and produce a topographical map on a scale of 1∶500?000. Lewis’ decision met with much resistance from within the country and abroad, but the project was completed in a record period of 4 years. Published just before the Second World War, the map was of inestimable value to the South African Defense Force. It not only became the standard topographical map of large parts of South Africa for many years, but its contents also figured in the first map series of the TSO. 相似文献
11.
《测量评论》2013,45(9):163-166
AbstractThe survey of Sierra Leone was fortunate enough to be completed just in time before the economic blizzard (if I may be permitted a well-worn journalistic cliché) descended on West Africa in common with the rest of the world and largely curtailed such activities. I do not propose to deal here with its technical side to any great extent. An excellent account of bush surveying is to be found in the “Handbook of the Southern Nigerian Survey”, which account always filled me with the greatest awe and respect for the men working there, their output being vastly greater than anything we were able to achieve in Sierra Leone. Truly “there were giants … in those days”. 相似文献
12.
《测量评论》2013,45(74):162-174
AbstractThe comprehensive paper on the suspension of tapes by M. Hotine in the January, 1939, issue of the Empire Survey Review (v, 31, 2) did not contain any reference to this question, as was pointed out by A. J. Morley in a letter published on page 261 in the same volume (v, 34, 261). A brief analysis has been made by F. Yates of the theoretical effects of pulley eccentricity and misalignment (“Gold Coast Survey Department Records” VoL III, 1931, page 43) but I have not seen any further reference to the subject and have recently experienced the effects of such a defect in our own apparatus, so the followingnotes nlay be of interest. Before proceeding to details I will describe briefly those parts of the apparatus which are considered here and give a short summary of the whole paper. 相似文献
13.
AbstractThe third Empire Surveyors' Conference has come and gone. It fully bore out the promise of its predecessors and was most interesting and instructive for all those who attended, as it will certainly prove to be for readers of the forthcoming Report. This year's gathering was noteworthy particularly for the better representation of the self-governing Dominions; Messrs. Peters, Percival, and Whittingdale, representing respectively Canada, Australia, and South Africa, formed a worthy trio to hold the Dominion bridge, while there were present also, besides the colonial delegates, Brigadier Couchman, the Surveyor-General of India, and a strong contingent from the Mother Country. 相似文献
14.
《测量评论》2013,45(20):339-343
AbstractSome time ago during a conversation in the Geographical Section, General Staff, the question of the ages of both Stonehenge and Woodhenge cropped up. As I was at that time stationed at Larkhill Camp, within easy reach of both, it was suggested that I might arrange to observe the azimuths of the axis lines of these two circles, in the hope that such information might be useful in determining which was really the older. This was done, but I regret that pressure of work has meant such a long delay before the resul ts have been made available. 相似文献
15.
《测量评论》2013,45(12):322-328
Abstract The Ordnance Survey after the War.—I might class the four years after the War, during which I remained at the head of the Ordnance Survey, as interesting but troublesome. As is well known, an entirely unreasonable impression was spread about that, now that the War was over, there would be a period of great prosperity, and that we should all live like fighting cocks. Well, things did not work out like that. There was a Select Committee on National Expenditure (1918), and this Committee recommended a lengthening of the period of revision of the large-scale maps of the United Kingdom and a consequent, ultimate, reduction of establishment by 500 men. The Treasury later on insisted on a reduction by 600, including Ireland. 相似文献
16.
《测量评论》2013,45(76):242-255
AbstractDuring the last year, the Air Survey Section, Field Division, Ordnance Survey, have had many visitors. Most of them have been surprised at what they have seen: some at the fact that we are able to make so much use of air photographs even in the largest scale surveys, and some at the small amount of information we seem able to extract from them. This paper is an attempt to give in some detail the ways in which air photographs are used to solve the problems of the Ordnance Survey, why they are used and their limitations for our purposes. 相似文献
17.
《测量评论》2013,45(25):153-156
AbstractIn a previous Article (Empire Survey Review, ii, II) I described a simple graphical method for the elimination of latitude error in observations for azimuth. It was pointed out that the ideal method of adjustment of azimuths would be a simultaneous elimination of both latitude and refraction errors and, with that in view, a purely theoretical method of such an adjustment was demonstrated in the last paragraph of the article. It has now occurred to me that a fairly simple mathematical solution is possible. 相似文献
18.
DEM-induced errors in developing a quasi-geoid model for Africa 总被引：2，自引：0，他引：2
Errors in digital elevation models (DEMs) will introduce errors in geoid and quasi-geoid models, via their use in interpolating free-air gravity anomalies and (in the case of the quasi-geoid) their use in computing the Molodensky G
1 term. The effects of these errors and those of datum shifts are assessed using three independent DEMs for a test region in South Africa. It is shown that these effects are significant and that it is important to choose the best-possible DEM for use in geoid and quasi-geoid modelling.
Acknowledgments.The land gravity data used for this research were provided by the South African Council for Geoscience. Marine gravity anomalies were provided by the Danish National Survey and Cadastre (Kort & Matrikelstyrelsen). The GLOBE DEM was provided by the US National Geophysical Data Centre, and the CDSM DEM was provided by the South African Chief Directorate for Surveying and Mapping. The constructive comments of the reviewers are gratefully acknowledged. 相似文献
19.
《测量评论》2013,45(18):203-218
AbstractThe gear used for the measurement of the Kate Base of the East African Arc was specially designed by McCaw in conjunction with Messrs. Cooke, Troughton, & Simms, as a result of considerable experience in the measurement of geodetic bases in Fiji, Sweden, and in various parts of Africa; it is now known by the trade name of the “Macca” Base Measurement Gear. It has since been used in Southern Rhodesia, Tanganyika, Mauritius, and South Africa, and if the central pool of instruments recommended at the recent Empire Surveyors Conference is approved, it seems likely that its beat will soon be still more extended. It must be about the only first model of a surveying instrument which has not occasioned widespread controversy and complaint, and for this desirable state of affairs it is not unreasonable to suppose that the rare co-operation between the practical surveyor and the instrument-maker in its design is responsible. 相似文献
20.
《测量评论》2013,45(12):352-357
Abstract Preliminary Note.—The substance of this article was written in 1921 at the request of Lieut-Col. Wolff, who was then in charge of the Levelling Division of the Ordnance Survey and with whom the author collaborated in writing “The Second Geodetic Levelling of England and Wales, 1912–21” under the direction of Sir Charles Close. It was not intended for publication and was not again considered until 1928, when a discussion by correspondence was started by the Surveyor-General of Ceylon on the subject of hill circuits in levelling. In this discussion the survey authorities in Great Britain, Canada, India, and South Africa took part, but the main theme was the accumulation of error due to the large number of sightings necessary in hilly country and the question whether a common formula for such country and for flat country was justifiable. In his contribution Dr. van der Sterr made a brief allusion to the subject of the present paper and Dr. de Graaff Hunter went into details. His contribution and the following remarks therefore have some arguments in common. 相似文献