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1.
《测量评论》2013,45(62):300-311
AbstractChesterton did not, of course, intend this gibe to be taken literally. But the more we consider what he would doubtless have called the “Higher Geodetics”, the more we must conclude that there is some literal justification for it. Not only are straight lines straight. A sufficiently short part of a curved line may also be considered straight, provided that it is continuous (i.e. does not contain a sudden break or sharp corner), and provided we are not concerned with a measure of its curvature. Similarly a square mile or so on the curved surface of the conventionally spheroidal earth is to all intents and purposes flat. We shall achieve a considerable simplification, without any approximation, in the treatment of the present subject by getting back to these fundamental glimpses of the obvious, whether the formalists and conformalists accept them or not. 相似文献
2.
《测量评论》2013,45(50):161-162
AbstractThe article on the above subject by Mr. H. F. Rainsford (E.S.R., vi, 45, 404–407) investigates very thoroughly one error in catenary taping, but overlooks two other equally serious errors, namely the uncertainty of the weight of the tape and the uncertainty of the tension applied to it. 相似文献
3.
《测量评论》2013,45(31):2-36
AbstractThe method of accurate linear measurement by means of suspended Invar steel tapes or wires has, since its introduction by Jäderin about the beginning of this century, entirely replaced the older methods of base measurement by bars or rods. It is not surprising, therefore, that the theoretical basis of the method—including a determination of the form of the curved tape and of its horizontal projection—should have received close attention. The most valuable recent contributions to the subject, since Benoit and Guillaume's classic work La Mesure Rapide des Bases Geodesiques, are by Professor and Major Henrici and by the late Mr A. E. Young. 相似文献
4.
《测量评论》2013,45(72):67-74
AbstractSince 1899 cadastral mapping in the Sudan has been concentrated along the banks of the Nile from the Egyptian frontier to latitude 13°N., in the towns, and in the area of the Gezira, south of Khartoum, where cotton has been developed. These surveys were controlled by theodolite and steel tape either in the form of traverses or rectangulation. The early triangulation was used mainly to control topographical surveys, for it was essential to cover the whole country as rapidly as possible with a series of maps on scale 1: 250,000. As a consequence much of this early triangulation is of a relatively low order of accuracy, indifferently marked on the ground, and unfit for inclusion in a framework for medium and large scale mapping. 相似文献
5.
《测量评论》2013,45(89):110-115
AbstractThe difficulty of determining the true temperature of a surveying tape when in use in the field, particularly in bright sunlight, is discussed. A simple form of resistance thermometer made of invar tape is described and the results of comparisons made between the temperatures determined by this thermometer and those recorded by mercury thermometers under various conditions in the field are summarized. Under cloudy conditions, mercury thermometers, with bulbs screened or unscreened and as normally used by surveyors, gave results at all temperatures between O°C. and 25°0. within ±1°C. of the temperature indicated by the resistance thermometer. But in bright sunshine in Southern England, a mercury thermometer was found to record temperatures as much as 4°C. lower than that indicated by the resistance thermometer.It is not practicable in the field to use the invar measuring tape itself as a resistance thermometer; the Use of a resistance thermometer made of invar tape and situated in the neighbourhood of the measuring tape is therefore recommended for determining the mean temperature of a measuring tape when working in bright sunlight. 相似文献
6.
《测量评论》2013,45(78):366-368
AbstractThe method of reducing circummeridian altitudes or zenith distances to the meridian, using the factors m and n as tabulated by Chauvenet, is well known. The following method, which does not use these factars, has been faund both more convenient and more accurate in practice. The formula can be easily obtained by expanding m and n in powers of t, but far the sake af campleteness the derivatian is here given from the beginning. 相似文献
7.
AbstractI. Introduction.—Map projection is a branch of applied mathematics which owes much to J. H. Lambert (v. this Review, i, 2, 91). In his “Beyträge zum Gebrauche der Mathematik und deren Anwendung” (Berlin, 1772) he arrived at a form of projection whereof the Transverse Mercator is a special case, and pointed out that this special case is adapted to a country of great extent in latitude but of small longitudinal width. Germain (“Traité des Projections”, Paris, 1865) described it as the Projection cylindrique orthomorphe de Lambert, but he also introduced the name Projection de Mercator transverse or renversée; he shows that Lambert's treatment of the projection was remarkably simple. 相似文献
8.
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
9.
《测量评论》2013,45(14):472-484
Abstract Choice of Beacon.—The general question as to whether luminous or opaque signals should be used in ruling triangulation has recently been discussed in the Empire Survey Review (No.9, pp. 151–2 and No. 12, pp. 335–6). It may here be summarized that opaque beacons of suitable design are sufficiently accurate and offer the considerable advantages of being immediately available for subsequent work, of requiring little or no attention, and of being visible from all directions without rearrangement. Moreover, if of the tripod or quadripod type, they need not be dismounted during occupation of the station for observing, so that 0bservations by more than one observer are not interrupted. The only occasion for using luminous beacons arises from bad visibility, whether through atmospheric haze or lack of a suitable background or through the economic necessity of completing observations at night. These conditions are not peculiar to ruling triangulation. An ”all-round” type of luminous beacon—a pressure oil lamp or a rotating mirror system—can be used for nightwork or against a dark background, but single-direction luminous beacons are necessary to overcome haze. 相似文献
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11.
《测量评论》2013,45(47):30-35
AbstractIn the Empire Survey Review for October 1938 (iv, 30, 480) a simple demonstration of the condition to be satisfied for conformal representation was given. This condition may be expressed by the equation w = f(z), where w and z are complex variables representing corresponding points in the w-plane and z-plane respectively, and f(z) is an analytic function of z. 相似文献
12.
《测量评论》2013,45(15):2-5
AbstractIN the July issue of the Empire Survey Review, vol. ii, no. 13, pp· 424–8, there appeared a review of precise theodolite investigations carried out by the present writers; the original papers were published in the March, 1934, number of the Canadian Journal of Research of the National Research Council, Ottawa. The elaboration of some points which could not be given much space either in the original papers or in the review may be of interest. 相似文献
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14.
《测量评论》2013,45(25):140-151
AbstractThe subject of the training of European surveyors has received a great deal of attention in the course of the last two Empire Conferences, but little or no mention has been made of the native surveyor, his education, work, and prospects. The subject is very important, however, and the account of the training of Africans for the N. Rhodesia Survey, which appeared in vol. iii, no. 21 of the Empire Survey Review, was read with considerable interest. It may not be out of place, therefore, to introduce this paper on the means adopted in Malaya to recruit and train an efficient staff of subordinates or “Technical Assistants” as they are termed locally. 相似文献
15.
《测量评论》2013,45(20):354-358
Abstract 6. Further Expansions.—Equations (4.3) and (5.5) enable a computer to transform coordinates from the Cassini projection to the Gauss projection without recourse to geographical coordinates. If applied to one or two points, no doubt these equations would be quite satisfactory; but if applied to 100,000 points their use would be laborious and it would be difficult to adapt them to machine computing. 相似文献
16.
Abstract The recently launched SPOT 1 satellite belongs to a family of second generation remote sensing spacecraft which has been designed to ensure more than 10 years of continuity for the corresponding data delivery. Starting with the model 1 of the satellite series, the paper describes successively its sun synchronous orbit, the 2 identical imaging instruments and the other subsystems such as the on board tape recorders, the telemetry package, the stabilization equipments and etc. Special emphasis is given to the technological innovations put into the design of this satellite, and its twin model 2, with respect to the first generation satellites represented by the three first spacecraft of LANDSAT Series. The paper then details the improvements carried out on the design of the 3rd and 4th models, to ensure the service continuity beyond 1990, and to deliver even more powerful data in terms of potential applications. 相似文献
17.
《测量评论》2013,45(12):345-346
AbstractIn the course of his stimulating and suggestive paper in your recent issue, No. ro, pp. 226–38, Mr. A. J. Potter writes on p. 233 “but there is no simple construction by which X can then be found”, and again on p. 237 “a direct construction, if there be such”. This cheerful challenge invites the construction of a circle centred on a given line, passing through a given point thereon, and touching a given circle, and I have found the lure of Mr. Potter's gauntlet as irresistible as its recovery has proved delicate. In order to shoulder responsibility and by no means to claim highly improbable originality, let me confess that the problem is new to me and the two constructions I offer are my own; I venture to hope that Mr. Potter may consider one or other of them not unworthy of his epithet “simple”, though I freely admit the aptitude of his empiric procedure to its purpose. The proofs are not long, but for fear of overshooting my welcome I offer them to anyone for the asking; and for the same reason my diagrams are small and therefore mere. 相似文献
18.
《测量评论》2013,45(26):216-221
Abstract By kind permission of the Editor of the Royal Engineers Journal, this paper has been adapted from the article by the Author in the issue of June 1937 (Vol. li, pp. 217–223). We are also indebted to the Editor for placing generously at our disposal the blocks used to illustrate the paper. 相似文献
19.
《测量评论》2013,45(15):55-56
AbstractI regret that my note on this subject (vol. ii, no. 7,PP· 32-3) should have apparently provoked so little comment or interest. I feel that the silence may be either that accorded to my Impetuous Inrush or that produced by alarm at the possible complications to be overcome before theory can be reconciled with practice. If the latter, then my original title is perhaps in some measure responsible. It is really very simple; let two facts suffice. 相似文献
20.
《测量评论》2013,45(45):402-407
AbstractWhen a line is being measured with a steel tape suspended in catenary but standardized on the flat, the correction for sag is usually computed from the weight of the tape. It can, of course, be determined by actual measurements on the ground, if these are made both on the flat and in catenary, but this is not usually done as it is a tedious process in the absence of a proper standardizing base. 相似文献