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1.
《测量评论》2013,45(9):151-156
AbstractMr. Clendinning's article on “Signal Lamps” (E.S.R., vol. ii, pp. 15–18) raises a point of major importance in geodetic triangulation. I entirely agree with him that the sole use of heliographs—heliostats to the purist—is in most parts of the world out of date. I also think, and indeed am prepared to state categorically, that the use of acetylene lamps is out of date and was out of date many years ago. The Americans, who are always worth listening to on the economics of surveys, would not otherwise have replaced all their acetylene gear by electric beacons. The answer, in my experience, and for reasons which I shall endeavour to make clear, is generally, but not necessarily always, to provide both helio and electric lighting; but first I should like to summarize the conditions in which luminous signals should be used at all. 相似文献
2.
《测量评论》2013,45(26):194-206
Abstract Reconnaissance.—It has been possible to draw up a “paper scheme” for most of the primary triangulation by examination of large-scale topographic maps for possible obstructions to the proposed rays (after due allowance for curvature and refraction along the ray); the fact that certain of the proposed lines had been definitely observed in the existing primary or secondary triangulation was of course of material assistance. Since, however, all observations were to be to luminous beacons, requiring a close organization, it would have been unsound to draw up an observing programme on the strength of this paper scheme alone. The omission of a few key rays, subsequently found to be obstructed by timber, whose height cannot be appreciated from maps, or by local features which had grown up since the last triangulation, would have entailed some confusion in the observing programme, the establishment of additional stations for occupation during a later season, and the reoccupation of stations surrounding such additional points; in short, the probability of a year's delay in obtaining sufficient material for adjustment, and a considerable loss of economy. Arrangements were accordingly made for the paper scheme of the English main chain to be verified and amended on the ground by special reconnaissance parties in 1935, when in fact no instruments or beacons were available to commence observing in any case. In the same way, field reconnaissance of the Scottish main chain and of the Western figure (Wales and the S.W. peninsula) was completed in 1936 and a start made on the Eastern figure (East Anglia and S.E. England), so as to get the reconnaissance and station preparation well ahead of observing. Experimental reconnnaissance of a few secondary blocks—for which, as also for the primary reconnaissance of the flat enclosed East Anglian country, paper schemes are practically useless—was also commenced in 1936 and is being pushed ahead rapidly in 1937. 相似文献
3.
《测量评论》2013,45(12):357-367
AbstractThe only essential difference between geodetic triangulation and any other of the fifteen “orders” of triangulation—which were once proposed, and happily rejected, at an International Conference—is that steps are taken to secure the high degree of accuracy necessary over the large areas to be covered. Some of the steps taken to secure increased accuracy may well be used to insure economy in secondary work, as for instance the use of fewer readings of a large instrument, or the use of luminous signals in conditions of poor visibility; while any surveyor may at any time have to connect his work to a geodetic triangulation, using much the same methods. 相似文献
4.
《测量评论》2013,45(12):335-340
AbstractFollowing recent discussions in the E.S.R. some experiences in Sarawak may be of interest.The argument for opaque beacons has been strengthened by the experience here of the past season, when combined day-and-night observing was carried out on the primary series, the daylight pointings being made to black-painted opaque beacons. No difference in the accuracy obtained by the two methods was noticeable in the results. Beacons were necessary in any case for the breaking down to secondary points. 相似文献
5.
《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
6.
《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
7.
《测量评论》2013,45(38):495-496
AbstractReports, appearing from time to time on the results of completed triangulation, show a variety of methods of construction of beacons. These range from temporary brushwood and calico signals to something of a more permanent nature. No doubt the purpose of the work, the type of country, local conditions, methods of observing, and finance, all enter into a decision as regards the necessity for the type of beacon to be used. 相似文献
8.
《测量评论》2013,45(71):2-13
AbstractSince a number of factors have combined to separate the second part of this paper from the first appearing in the E.S.R., issue No. 63, Volume IX, pp. 1–14, and written by Sir Ernest Dawson, I feel that some emphasis, already given, may reasonably be reproduced. To quote from Sir Ernest's paragraph on the Main Problem :—“The crux of the matter which I had been invited to solve, was the definition and record in a simple, sure and economical way, of the increasing number of unstable small holdings in their tangled setting throughout the Protectorate.” 相似文献
9.
《测量评论》2013,45(61):264-267
AbstractIn adjusting a triangulation network it may happen that certain condition equations, of the existence of which we know a priori (by formulæ or by plotting the network point by point), cannot be established by simple inspection of the figure. This usually happens when some of the observations are missing in the otherwise continuous network. Such equations, not readily identifiable from the diagram, may be called “implicit” condition equations. 相似文献
10.
《测量评论》2013,45(5):203-206
AbstractMR. C. O. GILBERT'S article on “Beacon versus Deed-plan” (E.S.R., Jan. 1932, pp. 98–99) raises a question of very great importance in those countries which have a system of land registration. In addition to the legal and technical aspects of the question, it raises the very important question of preservation of beacons and replacement of lost beacons. As he mentions the South African practice, the experience of the Transvaal may be of interest to readers, the more so as the case, The African and Buropean Investment Co., Ltd. and Others versus John Warren and Others, which he quotes, concerned farms situated in the Transvaal. I also wish to refer specially to the Transvaal, because there the diagram or deed-plan is of great legal force when there is a conflict between the position of a beacon on the ground and the position accorded it by a confirmed diagram. 相似文献
11.
《测量评论》2013,45(32):92-93
AbstractIt is laid down in the Survey Rules of Northern Rhodesia that all areas to be alienated under freehold title or long lease must be surveyed by triangulation and that traverse methods must not be employed without the permission of the Commissioner for Surveys. This of course is all very well under normal text-book conditions, but there comes a time when triangulation is neither safe nor economical. Such conditions prevail in the Copperbelt districts of N. Rhodesia, where the bush is thick, the terrain more or less flat and the haze usually considerable. To make things a little more difficult the countryside is littered with anthills, both small and large; some as much as 30 feet high and 100 feet in circumference at the base. Traversing under these conditions can be very interesting and at times definitely backbreaking. 相似文献
12.
L. S. Lyubivaya 《地理信息系统科学与遥感》2013,50(2):146-151
The author investigates the use of “added parameters” in the adjustment of analytical photo-triangulation to compensate for unknown systematic errors in the system. The model selected for investigation is one proposed by D. Brown which, in the opinion of the author, contains terms which are highly correlated and, as such, degrade the solution. The discussion goes on to propose a statistical method for selection of parameters and provides numerical results of applications of the method proposed. Investigations show an improvement in accuracy of typical analytical triangulation to be in the order of about 1.1 to 3.0 times when using the method. Translated from: Geodeziya i kartografiya, 1984, No. 1, pp. 34-38. 相似文献
13.
AbstractThe majority of readers are doubtless aware of the masterly summary of the “History of the Calendar,” written for the Nautical Almanac for 193I (pp. 734–747) by Dr. J. K. Fotheringham. Most are probably also aware that the question of Calendar Reform has been considered by the League of Nations. At the Conference on Communications and Transit of 1931, October 19, the League adopted a resolution recommending a fixed Easter, but declared that “the present time is not favourable … for considering … a reform of the Gregorian calendar.” For information on the various measures of reform proposed at Geneva the works noted below may be consulted. In the meantime, pending the coming of reform—for come it will—readers may desire to.have a summary history of the question, with a statement of a solution which is of somewhat the same nature as others which have been proposed. 相似文献
14.
《测量评论》2013,45(11):264-268
AbstractI may say at once that this article has nothing to do with either the Gaiety chorus or the “Old Firm”: it is merely a statement of what seem to me the fancies in Dr. de Graaff Hunter's paper “Figures of Reference for the Earth”, E.S.R., No. 8,pp. 73–8. Many readers of the Review will share my gratitude to Dr. Hunter for his lucid presentation of the theory underlying the usual geodetic processes. I disagree with only one of his points, and its implications, but unfortunately that point is fundamental. 相似文献
15.
AbstractAn additional note on these problems, which were considered in No. 23, pp. 49-53, appears desirable. The “alternative form” on p. 51 was presented in a manner calculated to demand an explanation; since none has been forthcoming no apology is necessary for a further reference. 相似文献
16.
《测量评论》2013,45(36):358-363
AbstractFew, most certainly, will dispute the value of Mr Black's paper describing a method of “Systematic Relaxation”, which appeared in a previous number of this Review. At the same time, however, it seems to the writer to be only fair to readers to point out that the application of the method to triangulation adjustment is really a treatment, from a slightly different aspect, of methods that have long been established. 相似文献
17.
A review of Soviet research describes methods of combining remote sensing and geodetic data in cartometric data bases—for the purposes of compiling more detailed and accurate “three-dimensional” terrain maps. The major objective is to provide, by means of photogrammetric techniques employing stereopairs or series of overlapping images, elevational data on selective key geomorphological points (along structure lines, summits of ridges, valley bottoms, etc.) which can be used to supplement (or replace) data obtained for the control points of a rectangular grid. Creation of digital models from these “geomorphological” points provides more accurate three-dimensional terrain maps. Translated from: Vestnik Moskovskogo Universiteta, geografiya, 1986, No. 6, pp. 56-64. 相似文献
18.
《测量评论》2013,45(28):334-338
AbstractI Hope Dr Wolff's interesting article will stimulate to action some of those who have not given sufficient attention to air survey as a method of mapping or planning those areas which lend themselves to that method. At the same time, whether so many of us are as conservative as the author appears to think is a matter for doubt, and moreover we do not all look upon air survey as an “innovation”. As Dr Wolff writes from Palestine he might be interested to know that as the second British Officer to take up field survey work in the War in 1915—Major (now Brigadier) Winterbotham being the first—I was one of the earliest in my profession to study, and to assist in the development of, air survey. In 1915 our unit in the 3rd Army was the first to make use of air photographs for the production of a regular series of trench maps. There are consequently few surveyors more interested in the method. I have watched the progress of the science and the work of the Air Survey Committee with continued interest and have used air methods whenever these have been possible or suitable. On my last visit to Paris I tried my hand at plotting with a new instrument at the Service Géographique and was much impressed by the work that was being done. 相似文献
19.
Abstract Air.—Any good Guest Night tune which happens to fit to a first order, and remains more or less in tune after subsequent orders. “Coming down the Mountain” and “Kabul River” would do. 相似文献
20.