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1.
《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
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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
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《测量评论》2013,45(20):322-325
AbstractTo the average man the sight of the Fellows of an Oxford college losing their tempers over the meaning of a Greek particle would certainly have something of the comic. No doubt it would seem just as comic to him that there should be any controversy over such a minor matter as map-grids. Yet they have some importance to the surveyor. What exactly is a map-grid? 相似文献
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《测量评论》2013,45(15):23-25
AbstractIN the absence on leave of the Surveyor General, a full Report for the Colonial Survey Committee was prepared by Mr. R. W. E. Ruddock, the Deputy Surveyor General. The Department in Ceylon covers so many activities that it would be impossible to mention here more than a few. 相似文献
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AbstractIn the last issue there was given an outline of modern theories on crustal equilibrium. The assumption as to uniform attenuation of matter beneath an elevated station suggests that an explanation of a means for calculating this “compensation” would be desirable; the complete technical procedure used by those actually engaged on work of this nature could be described by themselves alone. 相似文献
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《测量评论》2013,45(1):24-31
AbstractThe adjustment of a chain of triangulation for scale between measured bases is a comparatively simple matter. If it were possible to provide a similar method of adjustment for swing between measured azimuths and if the triangulation were based on a fixed datum, then there would be some hope of holding the chain fixed, without waiting until the completion of further chains rendered a net adjustment possible. This would be well worth doing. 相似文献
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AbstractAbout sixteen years ago an apparent need of the time led the writer to consider the construction of a small-scale map of the British Empire. It was immediately obvious that such a sheet, prepared in a manner to reduce the errors of scale and bearing to figures approaching the minimum, would have to extend from the Yukon and across the Eastern Hemisphere to New Zealand_ Accordingly, it would involve an oblique projection, cutting the Equator at some angle to be investigated. Moreover, the depth of the map would necessarily be the least possible in order to conform with the desiderata above. 相似文献
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AbstractUnits of length are tools of the surveyor. Even should he himself, as is unlikely, evince no interest in their origin, he may reckon on being consulted at some time by someone who is interested. And if to such an inquiry he replies that his business ends with a knowledge of their use, it is to be feared that knowledge of their present use would not be held to excuse ignorance of their past history. 相似文献
9.
《测量评论》2013,45(25):153-156
AbstractIn a previous Article (Empire Survey Review, ii, II) I described a simple graphical method for the elimination of latitude error in observations for azimuth. It was pointed out that the ideal method of adjustment of azimuths would be a simultaneous elimination of both latitude and refraction errors and, with that in view, a purely theoretical method of such an adjustment was demonstrated in the last paragraph of the article. It has now occurred to me that a fairly simple mathematical solution is possible. 相似文献
10.
《测量评论》2013,45(15):16-23
AbstractTHE formula for the projection is based upon the spherical assumption. To calculate it for the spheroid might be very complicated and would not be worth while. The projection is suitable for very large areas as a compromise between the Zenithal Equal-area projection on the one hand and the Zenithal Equidistant or Zenithal Orthomorphic on the other. Its application to an area as small as the British Isles would not serve any useful purpose. An analysis of its errors in the general case reveals some unexpected simplicities. This analysis is given below, followed by its application to the particular case of the British Isles on the ten-mile scale. This is done merely to find out what changes would have occurred if the supposed drawing of that map on Airy's projection had been real. 相似文献
11.
AbstractThe proof of the attraction of a uniformly thin vertical block in the last issue (No. 24, p. 87) does not appear as satisfactory as the textbook would suggest. It is proposed to attempt here a more direct explanation, independent of substitutional expedients. 相似文献
12.
《The Cartographic journal》2013,50(3):265-268
AbstractA main component of an Intelligent Transport System (ITS) is the navigation system to be used in the 'intelligent' vehicle. In fact, driving a vehicle is a complex task as the driver has to control the vehicle as well as make decisions about getting to his/her destination. Too much information on the map (i.e. a complex map) would confuse the driver, while too little information would not be sufficient for the user to compare with the actual environment. Sufficient information but poorly presented would also result in confusion.This paper reports on a study of the design of dynamic maps for land vehicle navigation through an investigation of different designs with different levels of information contents and visual effects using various dynamic variables. Different colours were assigned to the road and building names according to the position of the vehicle, and blinking symbols were used to indicate direction restrictions. Also, a set of maps with different degrees of complexity was designed such that the users would be provided with different levels of contents and representation by zooming in and out. The effectiveness of the design was investigated in the map evaluation process. 相似文献
13.
《测量评论》2013,45(10):201-206
AbstractThe division of a triangle into three lots of equal area by lines, drawn from a point within it perpendicular to the sides, appears at first sight to be a very simple problem, in which an average surveyor would experience no difficulty in performing the necessary computations for the determination of the position of the required point where the division lines meet. 相似文献
14.
《测量评论》2013,45(44):322-324
AbstractIn the last three years about 250 miles of “precise” traverse have been surveyed in this country to provide control for detail surveys. A brief account of the results may be of general interest. The traverses are situated where trig. points are far apart, and the cost of subsidiary triangulation would have been excessive on account of the flat nature of the country. 相似文献
15.
《测量评论》2013,45(23):38-41
AbstractMany surveyors, even those of wide experience, would, if questioned, assert that, at any given pointing of a theodolite, all points in the field of view which lie on the horizontal wire are at equal angular altitudes above the horizon, provided that the horizontal wire is in correct adjustment to the trunnion axis. 相似文献
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《测量评论》2013,45(7):24-28
AbstractMeasured deviations of the vertical have been used in support, or in destruction, of such pleasant little diversions as the theory of isostasy. They have also been used to adjust a triang~lation for swing, by methods which may fairly be criticized; but they have not, as far as I know, been used for reducing the horizontal measures of a triangulation to the standard conventional level of the spheroid of reference. In most cases such corrections would, of course, be too small to worry about, but it by no means follows that they are always small. In the case of a continental arc of meridian traversing a very disturbed mountainous region exhibiting certain constant tendencies, it should at least be demonstrated that they are small before the question can be considered finally settled. 相似文献
19.
《测量评论》2013,45(98):164-177
AbstractIn the past there has been considerable discussion on the above subject in this Review. There is a bibliography at the end of this article in which the full titles of previous articles are given. For brevity, reference to them in the following text is made by number only. Recently, Gulatee summarized present knowledge and asked how other Survey Departments dealt with this matter. Consequently, it was considered that it would be helpful to set out in detail the procedure adopted by the Directorate of Colonial Surveys for obtaining trigonometric heights, with particular reference to primary and seoondary chains and nets. 相似文献
20.
AbstractIf the geographical co-ordinates, Φ0, L 0, and the azimuth A 0 at a station O of a triangulation undergo corrections, ?Φ0, ?L 0 and ?A 0, the geographical co-ordinates, Φ, L, and the azimuth A have to be re-computed for all the vertices throughout the whole triangulation. This is a tedious operation. It may be vastly simplified, however, by the employment of differential formulae. The derivation of these formulae would consume considerable space, so that the results alone are given here. 相似文献