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1.
《测量评论》2013,45(81):118-128
AbstractSurveying tapes of steel are much more satisfactory mechanically than those of invar, and are less subject to secular changes of length, but the magnitude of their coefficient of thermal expansion demands a closer knowledge of their temperature than can be obtained with ordinary thermometers suspended near the tapes. The measurement of steel tapes in terms of their electrical resistance has therefore been investigated. The history of this work is traced. The use of resistance methods has proved satisfactory in the field, and under Laboratory conditions at the N.P.L. the accuracy of 1 part in 2 millions in the measurement of the lengths of 24-metre and 100-foot tapes of steel is attained. Such steel tapes appear to have remained stable on the average within about 2 parts in a million in 25 years. 相似文献
2.
《测量评论》2013,45(78):338-348
AbstractRadar can be applied to surveying for precise measuren1ent of long lines, and as a navigational aid and position-fixing device for an aircraft performing a photographic survey. Trials of the radar method have recently been carried out in Australia using a modified “Shoran” equipment. The results of a large number of radar measurements of six distances, varying from 160 to 310 miles in length, indicate that an accuracy of 7 parts in 105 can be achieved. Equipment errors constitute the immediate limit to accuracy, but reasonable modifications would yield a figure of 2 parts in 105. Radar measurements can be completed in a fraction of the time required by normal ground survey methods, since a measurement of upwards of a hundred miles is made in a single step.As an aid to photographic surveying a straight-line track indicator actuated by data from the “Shoran” equipment has been designed and flight tested. Its performance enabled a pilot taking aerial photographs to keep the aircraft to within an average departure of less than 0.02 mile from any desired straight-line flight path. 相似文献
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《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
4.
《测量评论》2013,45(36):364-368
AbstractThe method to be described consists of the measurement of a short base and the computation of the distances to various points, to which rays have been drawn on a plane table. The angles at the two ends of the base are observed with a theodolite. This method will be referred to as the “Short Base Method”. 相似文献
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《测量评论》2013,45(43):274-284
AbstractRecently the writer of this article became interested in the conical orthomorphic projection and wanted to see a simple proof of the formula for the modified meridian distance for the projection on the sphere. Owing to the exigencies of the war, however, he has been separated from the bulk of his books, and, consequently, has had to evolve a proof for himself. Later, this proof was shown to a friend who told him that he had some memory of a mistake in the sign of the spheroidal term in m4given in “Survey Computations”, perhaps the first edition. Curiosity therefore suggested an attempt to verify this sign, which meant extending his work to the spheroid. This has now been done, with the result that the formula given in “Survey Computations”, up to the terms of the fourth order at any rate, is found correct after all. 相似文献
6.
《测量评论》2013,45(96):65-70
AbstractThe measurement of the temperature of a measuring band or bar has always been a major problem. A considerable a.mount of experimentation has been done on the morepreciseaspects of survey measurement, and attempts, ranging from packing measuring bars in ice to bimetallic apparatus, made to reduce temperature errors. At the present time electro-resistance thermometers are being used and an entire new field is being investigated using various waves for distance measurement. For at least some time in the future, however, these new techniques will not be sufficiently developed to be of practical or economic use to the cadastral surveyor. Nevertheless very much less interest is taken in what may be termed “bread and butter” procedures. 相似文献
7.
《测量评论》2013,45(69):318-322
AbstractThe Transverse Mercator Projection, now in use for the new O.S. triangulation and mapping of Great Britain, has been the subject of several recent articles in the “Empire Surpey Review. The formulae of the projection itself have been given by various writers, from Gauss, Schreiber and Jordan to Hristow, Tardi, Lee, Hotine and others—not, it is to be regretted, with complete agreement, in all cases. For the purpose for which these formulae have hitherto been employed, in zones of restricted width and in relatively low latitudes, the completeness with which they were given was adequate, and the omission of certain smaller terms, in the fourth and higher powers of the eccentricity, was of no practical importance. In the case of the British grid, however, we have to cover a zone which must be considered as having a total width of some ten to twelve degrees of longitude at least, and extending to latitude 61 °north. This means, firstly, that terms which have as their initial co-efficients the fourth and sixth powers of the longitude ω (or of y) will be of greater magnitude than usual, and secondly that tan2 ? and tan4 ? are likewise greatly increased. Lastly, an inspection of the formulae (as hitherto available) shows a definite tendency for the numerical co-efficients of terms to increase as the terms themselves decrease—e.g. terms in η4, η6, etc. 相似文献
8.
《测量评论》2013,45(59):175-183
AbstractIn the remarks which follow, the word “scope” will have the meaning given in the Concise Oxford Dictionary—“Sweep or reach or sphere of observation or action, extent to which it is permissible or possible to range, opportunity, outlet, vent”. Another good definition is “field of action”. The object of the paper is to show that greater efficiency will be obtained if all types of survey work in a country, except possibly railway surveys, are done under the supervision of, or by the staff of, a Survey Department of wider scope than is normal. 相似文献
9.
《测量评论》2013,45(55):26-27
AbstractEvery student of Close and Winterbotham's “Text Book of Topographical Surveying” learns that rewebbing diaphragms is a simple job. Unfortunately, when circumstances compel a surveyor to reweb a micrometer diaphragm in the field, he is liable to find, after some years in the tropics, that fever (and one thing and another) have played havoc with the steadiness of hand and eye. Under present conditions young surveyors who have been trained on optical micrometers may find themselves using 5″ micrometer theodolites with over a dozen webs, anyone of which is liable to sag, break or develop whiskers, while even a “Tavi” may conceivably remind the user that it has one web. 相似文献
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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
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AbstractOld text-books in English frequently referred in very loose terms to the “run of the bubble”. The meaning of the term was often so doubtful as to leave the impression that the writers themselves had vague notions on the theory of the level; certainly they must have left the student often in a state of bewilderment. In the sense in which it was used the phrase “run of the bubble” appears to have been intended to suggest a line parallel to the directrix. 相似文献
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《测量评论》2013,45(60):217-219
AbstractMap Projections.—A matter that should have been mentioned in the original article under this title (E.S.R., vii, 51, 190) is the definition of a map projection. In the list of carefully worded “Definitions of Terms used in Surveying and Mapping” prepared by the American Society of Photogrammetry (Photogrammetrie Engineering, vol. 8,1942, pp. 247–283), a map projection is defined as “a systematic drawing of lines on a plane surface to represent the parallels of latitude and the meridians of longitude of the earth or a section of the earth”, and most other published works in which a definition appears employ a somewhat similar wording. This, however, is an unnecessary limitation of the term. Many projections are (and all projections can be) plotted from rectangular grid co-ordinates, and meridians and parallels need not be drawn at all; but a map is still on a projection even when a graticule is not shown. Objection could be raised also to the limitation to “plane surface”, since we may speak of the projection of the spheroid upon a sphere, or of the sphere upon a hemisphere. Hence, it is suggested that “any systematic method of representing the whole or a part of the curved surface of the Earth upon another (usually plane) surface” is an adequate definition of a map projection. 相似文献
16.
《测量评论》2013,45(84):242-247
Abstract13. As mentioned earlier (xi, 83, 199) the “Final Village Plan”, which is evolved from the 4-chains-to-an-inch (1:3,168) “Block Survey” village plan after inquiry and settlement of claims as between the Crown and private parties, provides a sound basis for mapping-out and for the subsequent administration of the Crown estate. But as (in all cases) the development of Crown land could not await Block Survey and “Settlement”, it was also necessary to undertake mapping out in areas which had not been systematically surveyed, and for which no continuous large-scale plans were available. 相似文献
17.
《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
18.
《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
19.
AbstractIt sometimes happens that from a point on a line of theodolite traverse two fixed points are visible. In the absence of a visit to at least one of these points, B or C, or a precise knowledge of a bearing, it is not possible to fix absolutely the station, say A, of the traverse. Nevertheless, the fact remains that if the angle subtended by the fixed points is measured and found to be α, say, the station A must lie on an arc of a circle through BC “capable of” this angle α. Is there any assumption which is justifiable under these circumstances? 相似文献
20.
《测量评论》2013,45(69):282-295
AbstractSurveying in, the sense in which I propose to consider it this evening, is the technical term given to the science of admeasuring and delineating the physical features of the earth and of works executed or proposed upon its surface. I am in some difficulty over a precise definition which will satisfy everyone since, although “surveying” is generally understood in the English language to have the above meaning, there is a growing tendency to use the somewhat restricted term” land survey"; restricted since it implies omission of hydrographic, hydrological and other forms of measurement of natural features and of setting out. This is, of course, not so. 相似文献