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1.
《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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ABSTRACTThis paper proposed and evaluated an estimation method for indoor positioning. The method combines location fingerprinting and dead reckoning differently from the conventional combinations. It uses compound location fingerprints, which are composed of radio fingerprints at multiple points of time, that is, at multiple positions, and displacements between them estimated by dead reckoning. To avoid errors accumulated from dead reckoning, the method uses short-range dead reckoning. The method was evaluated using 16 Bluetooth beacons installed in a student room with the dimensions of 11 × 5 m with furniture inside. The Received Signal Strength Indicator (RSSI) values of the beacons were collected at 30 measuring points, which were points at the intersections on a 1 × 1 m grid with no obstacles. A compound location fingerprint is composed of RSSI vectors at two points and a displacement vector between them. Random Forests (RF) was used to build regression models to estimate positions from location fingerprints. The root mean square error of position estimation was 0.87 m using 16 Bluetooth beacons. This error is lower than that received with a single-point baseline model, where a feature vector is composed of only RSSI values at one location. The results suggest that the proposed method is effective for indoor positioning. 相似文献
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《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
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《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
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《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
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《测量评论》2013,45(7):34-44
AbstractIn June, 1931, a new start was made on the triangulation of Sarawak. The existing work consisted of a series of triangles measured in 1918–22, forming no rigid scheme and not capable of adoption or extension. A number of these stations were brought into the new scheme with either new beacons or the old repaired. The old stations embodied in the new scheme were: Serapi; Serambu (new bc.) ; Sejingkat (new ·bc.); Santubong (old bc. repaired); Satang; Undan (new bc.); Stapok; Sengai (new bc.); K. Rambungan; Salak (new bc.); Siol; Stabar. The new points established were: W. Base; E. Base; Sampadi (near old station); Buan Bidi; Selalang; Tundong; Serenggok; Bukit Satu; Kranje; Stigang; Golf-links; Bako. 相似文献
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Abstract Geospatial analysis of marine mineral placer deposits along the Gulf of Mannar is attempted. This study develops a method for the spatial anlaysis of data using geographical information system (GIS). Specifically, creating attribute data base structure, data encoding, data interpolation, and view shed analysis are attempted to delineate the opaque and garnet occurrences in the beach sediments. Data integration including the creation of digital files using TNT Mips software is performed. The interpolation of the spaced data is achieved by inverse distance weighed interpolation to define the zone of heavy mineral enrichment. This study has established the digital elevation model (DEM) capability to identify the potential beach placer zones in the study area. 相似文献
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《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
9.
Russell D. Johnson 《国际地球制图》2013,28(1):41-45
Abstract Remote sensing is a powerful and accurate means of collecting data for wildlife management, particularly for large areas which are difficult of access and feature delicate ecosystems. Giant panda habitat in the People's Republic of China was evaluated by visual interpretation of multitemporal LANDSAT MSS images. The resulting map, combined with ground survey data, provides important information upon which management decisions can be planned. This case study illustrates that remote sensing techniques can make a significant contribution to the management programme for the conservation of a threatened animal species. 相似文献
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《测量评论》2013,45(88):77-84
AbstractThis article discusses the observation equations which may be solved graphically by plotting position lines using the method of zenith distance intercepts, or solved analytically by the method of least squares.The general observation equation is modified for the particular case in which zenith distance is made equal to assumed co-latitude, thus simplifying the reduction of the observations.Adaptation of the theory to use with a theodolite is discussed together with the effects of sources of error and the methods which are proposed for their elimination.A routine of reduction is proposed and an example is given. 相似文献
11.
《The Cartographic journal》2013,50(2):73-76
AbstractThe role played maps in the planning of MiltonKeynes is described in this paper. MiltonKeynes is the latest of the new generation of New Towns in the United Kingdom.This paper was presented by the annual Symposium of the Society in September 1970 at the University of Bristol. 相似文献
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none 《The Cartographic journal》2013,50(2):181-182
AbstractNo statement appears to have been made at the time of why the national survey was put in hand in 1791. How far the Ordnance launched it in furtherance of its own responsibilities for the defence of the realm, and was therefore right to confer on the ordnance survey the prestige of its name, is a question which this article considers.The Board of Ordnance was a department of state which was already by then two and a half centuries old. Furnishing the ordnance survey with scientific and administrative skills and Ordnance also lumbered it with the political difficulties which led to its own demise. 相似文献
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《The Cartographic journal》2013,50(2):77-80
AbstractMaps play an important part in planning at national, regional and local levels. This role should increase ill the future as greater use is made of computers.This paper was presented to the annual Symposium of the Society in September 1970, at the University of Bristol. 相似文献
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《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
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AbstractThe following is a report of the discussion on the paper by Mr. A. R. Robbins on “Deviation of the Vertical” which was read at a meeting of the Land Surveying Division of the Royal Institution of Chartered Surveyors held on Tuesday, 12th December, 1950, and which was published in the January issue of this Review (xi, 79, 28–36). 相似文献
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《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