A SIMPLE PROPOSITION lN,TRIGONOMETRICAL SURVEY AND ITS USES

Abstract

1. The proposition which expresses in terms of the three sides the rate of change of the angle at the vertex of a triangle whose base is stationary and whose vertex is given a small displacement is an important one in plane survey. It must have beeJ1.known to some surveyors for a century or more but there is no doubt that even to-day it is not widely known. This, too, in spite of its extreme simplicity, which makes it, once known, impossible to forget. It's discoverer is unknown to the writer, who was somewhat intrigued to discover it for himself about 25 years ago in the course of field operations of the kind described in § V hereafter. The probability is that many people have discovered it independently.     

Mapping Everest

Abstract

From its inception in the middle of the 19th century, the Royal Geographical Society (RGS) took a keen interest in the exploration and mapping of the Everest region. This formed an integral part of the many Everest expeditions, some of which had individual surveyors or survey parties attached to them. Many mountaineers took part in this work, particularly those with a scientific background. But it was not until 1961 that a comprehensive map was produced of the Everest region.     

Editorial

Abstract

A reconstruction is made of the methods by which the Ordnance Survey of Great Britain pioneered a system for establishing the place-name nomenclature on its maps in the nineteenth century. Until 1820 there was little to differentiate the practice of the Survey from that of earlier cartographers but, thereafter, official surveyors were encouraged to consult a wide range of written and oral authorities and were instructed to record their findings in special name books. By the mid-nineteenth century the essentials of the modern system had been laid down and many thousands of local names published in map form for the first time.

This paper was read in a shorter form to the annual symposium of the Society in September 1970, at the University of Bristol.     

THE ORTHOMORPHIC PROJECTION OF THE SPHEROID–III

Abstract

In the last instalment we were able to obtain most of the surveyor's projections in common use by applying simple scale conditions to the meridians and parallels. This method of approach naturally suggests that results of some value might be obtained by applying similar conditions to the plane co-ordinate lines. If we do so, we are immediately led to consider curves on the surface known as geodesics, which are the nearest approach to straight lines it is possible to draw on a curved surface. Accordingly, we give some account of these curves for the benefit of surveyors who have not hitherto made their acquaintance.     

UNDER FIVE SOVEREIGNS: OR MILITARY SURVEYS FOR THE LAST FIFTY YEARS

Abstract

In Close's “Text-book of Topographical Surveying” there still appears, as Plate XVII, a specimen of small-scale plane-table work in Somaliland. It dates back to 1903. In the first edition of the Text-book, which to the joy of all soldier surveyors replaced the “Manual of Military Topography”, the letterpress referring to Military Surveys dealt entirely with rapid small-scale mapping and with hasty triangulations.     

THE MILITARY SURVEY SERVICE AND THE CIVILIAN SURVEYOR

Abstract

When Colonel Lambton of Indian fame wanted funds for his Survey a leading melnber of the Finance Committee of Madras observed that “if any traveller wished to proceed to Seringapatam he need only say so to his palankeen bearer and he vouched he would find his way to that place without having recourse to Colonel Lambton's map”. Those who have had the privilege of dealing with finance branches will recognise in this quotation a powerful tradition and it is a measure both of the great march of events since Lambton's time and of the deterlnination of military surveyors not to lag behind them, in spite of finance committees, that good military maps are nowadays taken for granted and that the large survey organisations, required to produce them are accepted as a necessity. The struggle to maintain this position however goes on.     

REWEBBING DIAPHRAGMS WITHOUT TEARS

Abstract

Every 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.     

SOME NOTES ON COMPUTING

Abstract

The article that follows is a collection of notes on various aspects of computing, some of them rather elementary, which it is thought might be of interest to some surveyors. Most land surveyors spend quite a lot of time computing and many become expert at it, but even so they rarely reach the stage when they cannot usefully pick up hints from professional computers. It is therefore hoped that it may be useful to collect a number of points which the writer sometimes found helpful to surveyors during the time when he was doing arithmetic for a living.     

SURVEY FOR COLONIAL DEVELOPMENT

Abstract

The Inaugural General Meeting of the newly-formed Land Surveying Division of the Royal Institution of Chartered Surveyors was held at the Headquarters of the Institution in London on Wednesday, 14th December, 1949, when the following paper was read by Brigadier M. Hotine, C.M.G., C.B.E., F.R.I.C.S., Director of Colonial Surveys. This meeting, which is the precursor of others that are to be held in future at regular intervals, is of particular importance to surveyors since it was the first occasion on which those of them who had joined the Institution recently, but. werenot members oj any of the Committees appointed in connection with theformation of the Land Surveying Division, had been able to meet together as a separate Division of the I nstitu.tion, and thus to take their part in one of the Institution's normal activities. Brigadier Hotine's paper, together with an account of the Proceedings of the meeting, was published in the January issue of the Journal of the Institution and readers who belong to the Institution will thus already have had an opportunity of reading it. A large number of our readers, however, do not belong to the Institution, and do not see the Journal, and hence, and especially considering the special importance of the occasion and the intrinsic interest to all land surveyors of the subject with which the paper dealt, we have obtained the kind permission of the Editor to reproduce from the Journal the text of the paper and of the discussion which preceded and followed it.     

SOME NOTES ON ASTRONOMY AS APPLIED TO SURVEYING

Abstract

Astronomy is not a subject that is taught much from text-books, and the excellent but rather out-of-date books such as Chauvenet and Ball do not contain many of the more modern methods. The writer, as a one-time professional astronomer, has been able to pick up various ideas about the sort of astronomy useful to surveyors, with which some surveyors may not be familiar and which might be useful to them. The whole of these notes are not entirely his own work, many of the details having been first suggested by the late Dr. L. J. Comrie, F.R.S.     

John Stanley Keates: Curriculum Vitae and List of Publications

Abstract

The first BCS President of the twenty-first century reflects on the cartography of the twentieth century and identifies those 'maps' that he believes have had significant influence on the development of the discipline during that century.     

ALTITUDES OF POINTS SEEN ON THE HORIZONTAL WIRE OF A THEODOLITE

Abstract

Many 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.     

A NEW METHOD FOR THE ADJUSTMENT OF A NETWORK OF TRIANGULATION

Abstract

A problem frequently encountered by surveyors in carrying out a system of triangulation, is the adjustment of a network of lower order triangulation to make it geometrically consistent with an existing triangulation of a higher order. For example, in Fig. 1 it will be assumed that the positions of the stations A, B, and C have already been determined and that it is now required to determine the positions of the stations a, b, c, d, e and f from the measured values of the internal angles of the network of triangulation shown. In practice, several different solutions have been suggested, ranging from rigorous least squares methods to semi-graphical solutions. The method described in this article is believed to be original and may prove of interest to surveyors.     

Mapping Palestine and Mesopotamia in the First World War

Abstract

The survey and mapping activities which took place in Palestine and Mesopotamia during the First World War need to be considered in their contexts, both of long-term British mapping activities in the region, and of survey and mapping generally during the First World War. Thus, while it is important to recognise the real technical advances in map-making which resulted from survey activities in the Near and Middle East during the First World War, it needs to be recognised that this was simply the culmination of nearly 80 years of British military mapping in the region. Each generation of surveyors used the most appropriate tools for the task in hand and the conditions under which the survey needed to be conducted. The First World War surveyors were fortunate that a new tool, aerial photography, had become available just prior to the war.     

THE REJECTION OF OUTLYING OBSERVATIONS

Abstract

The object of this article is to help surveyors and computers to decide whether one of several measurements of the same quantity ought to be rejected or not. No new theories are developed, but some explanation is given as t9 how the mathematical theory of statistics may be applied to measurements made in surveying.     

MODEL PLANE-TABLING

Abstract

The method of instruction in plane-tabling described below was introduced in the Survey of India in 1941 in connexion with the mass-training of Indian surveyors during the war. It has certain advantages which may be of interest to Survey Departments and instructional institutions elsewhere.     

LEAST-SQUARE SOLUTIONS WITH A CALCULATING MACHINE

Abstract

A Calculating machine may be used merely as a substitute for logarithms to perform the multiplications and divisions in a long computation. This is possibly the commonest use to which a machine is put by the majority of surveyors. Although a great saving of time is so obtained, the full potentialities of the machine are not realized until its fundamental properties are understood. In this article one very simple property of all modern calculating machines is used to develop a method for carrying out least-square solutions.