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1.
《测量评论》2013,45(45):393-401
AbstractThe first instrument of the new design of the Geodetic Tavistock theodolite was received by the Geodetic Service of Canada early in 1939. It has now been well tried out both in field and laboratory, and a few minor changes have been accepted by the manufacturer. The reactions of field men and the results of laboratory tests may be of interest. 相似文献
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AbstractIf the horizontal circle of a theodolite is tilted, the azimuth of a point in the field will be affected. The tilt may be a mere question of dislevelment but it may be also due to a deviation of the vertical which the level on the instrument cannot measure. In either case the effect on azimuth or bearing is of the same nature, which is worth consideration for more than one reason. That it has previously been investigated elsewhere is no valid reason against renewed consideration here, particularly as the consequences are probably unknown to some readers. 相似文献
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AbstractA Fully equipped theodolite is provided with plate levels, an alidade level, and a striding level. An instrument not so equipped has no title to be considered a “Universal Instrument”, that is to say, an instrument designed for every kind of both terrestrial and celestial measurement. Without a striding level, for example, nothing beyond relatively rough astronomical measures can be expected in general. Modern instruments, capable of giving considerable refinement in terrestrial measures, are frequently not furnished with a striding level; and it is sometimes assumed, with the tacit approval of the makers, that such instruments are equally capable of giving refined astronomical results. On the older type of instrument a striding level—rarely not supplied—could have been, and sometimes was, extemporized; it seems as if ignorance of astronomy of position has led, at least in part, to the construction of theodolites in such a manner as actually to render such extemporization difficult. 相似文献
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《测量评论》2013,45(26):206-213
AbstractRELATIVE to discussions on the Wild theodolite in the E.S.R. the following contribution considers some properties common to that instrument and the Zeiss II; perhaps to the Tavistock also, with which, however, the writer has had no experience on precise triangulation. 相似文献
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《测量评论》2013,45(42):194-205
AbstractThe following discussion of the mathematical theory of the transit theodolite adds, perhaps, nothing new to instrumental theory. It does, however, collect together matter which is scattered about in different text-books or, indeed, perhaps, in the same book, and may thus be of service to those interested. It was not prepared in the first place for publication in this Review, but the editor, having seen it, thinks that it may be of use to some readers and has thus asked for my permission to publish it. 相似文献
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《测量评论》2013,45(40):69-75
AbstractWhen a theodolite is used to measure an angle, the result will be subjected to certain instrumental and personal errors which affect the measurement. Such errors may be accidental or systematic. Those of the former type, which follow no law and which may with equal probability occur at any graduation, are more easily eliminated, since, if a very large number of readings is taken, it is probable that the errors will cancel out and that the mean will approximate very closely to the correct figure. Systematic errors are usually due to instrumental defects and rnay be expressed as a function of the reading itself; it is the object of the manufacturer to eliminate these as far as possible, since cancellation by reiteration or by repetition is not to be expected wholly. 相似文献
8.
《测量评论》2013,45(70):330-344
AbstractThe late war has been responsible for many unusual situations—not the least of which was that of certain British Colonial Surv1ey Offices passing under the control of an Asiatic Invader, and it is thought that the story of one of them—the Survey Department of Malaya—will not be without interest to readers of this Review. 相似文献
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《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
10.
《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
11.
《测量评论》2013,45(92):276-277
AbstractIn survey work connected with Seismic (Geophysical) investigations, the nature of the operations is such that provisional points many miles apart have frequently to be located with a minimum of delay. When no map and no triangulation exists, the range finding method about to be described is very useful. The method can also be recomlnended for reconnaissance and exploration surveys. It was used by one of the R.A. Survey Regiments with success during the war. The essentials are a good theodolite and a steel tape. 相似文献
12.
AbstractThe constant K in equation (12) represents distance expended through time lags in the instrument itself, and, although the value of K can be calculated from electrical data, this would not be very satisfactory and it would be better to determine it directly by means of observations over a line of known length. In addition, the point from which K would be reckoned is not a convenient one for actual field measurements. Instead of this, it is more convenient to choose an index mark on the instrument itself and referall measurements to this and thence to the mark over which the instrument is set up. 相似文献
13.
In recent years interest has been increasing in the use of measurements from single photographs for analytical work. A monocular instrument based on the theodolite is described, together with preliminary test results. 相似文献
14.
Erik W. Grafarend 《Journal of Geodesy》1985,59(2):124-138
Summary From a two-dimensional network adjustment it is well understood that the one orientation unknown of a theodolite frame is
estimable, once the orientation datum parameter, e.g., one azimuth, is fixed. In three-dimensional networks the problem of
estimability of three orientation unknowns inherent in a theodolite frame is more complex. Here we prove that not only the
classical horizontal orientation unknown is estimable (up to the datum degrees of freedom), but also astronomical longitude
and astronomical latitude which can be considered as two additional orientation unknowns of the theodolite frame moving with
respect to an earth-fixed equatorial frame of reference. Thus the theodolite instrument can be considered—at least theoretically—a
gradiometer measuring the variation of the directional parameters of the gravity vector from one point to another. Or up to
the datum degrees of freedom astronomical longitude and astronomical latitude can be determined from only theodolite observations
between exclusively terrestrial points. M?nicke (1982), has shown that despite the refraction problem the method works sufficiently
well in practice. 相似文献
15.
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
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AbstractThe optical principle of the deflection prism may not be known to all readers. Though there is nothing of very modern origin in the optics of a prism, as a wedge of very acute angle it possesses special powers which admit of useful adaptation to certain types of instrument. This application is a development of comparatively recent times. It will not be out of place, therefore, to make some reference to it in this Review. 相似文献
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《测量评论》2013,45(42)
AbstractThe Primary Triangulation did not cover completely the eastern end of the Island and it was required to carry the net out to the coastline in this region. Two additional primary stations have now been selected to admit of this extension. The lines straddle the John Crow mountains, which were one of the great obstacles at this end, and one point is actually on the lighthouse t at the eastern extremity of Jamaica. Since observations are needed from one side only of the lighthouse, we have put a special bracket on the balustrade of the lantern gallery to support the theodolite; the beacon is plumbed upside down below this. I enclose three photographs to illustrate it. 相似文献
20.
《测量评论》2013,45(5):214-217
AbstractIn order to minimize errors in Precise Levelling it is usual to stipulate a maximum distance at which a staff shall be held from the instrument. The determination of such a distance must result from a compromise between the demands of accuracy and economy, and this distance must of course fall between the lower limit, when because of nearness the instrument cannot be focussed on the staff, and the upper limit, above which the staff cannot be read distinctly. 相似文献