Maps and survey

Front matter

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Preface

'nr^HIS book is designed as an introduction to the study of •^ Maps and the processes of Survey by which they are made.

In planning the work it was necessary to decide in the first place whether to call it Maps and Survey, or Survey and Maps : that is to say, whether to take the logical order, of Survey before Maps, or the order of general interest and use, which is Maps before Survey.

Since many more people use maps than are engaged in making them, or than need to know the details of how they are made, it seemed better to begin with the consideration of the map as it is published and used. A clear understanding of the best results that have been produced up to the present time, leading to an appreciation of the ways along which progress is desirable, will make a convenient basis for the study of the methods of Survey, and the manner in which our representation of the world's surface may be extended and improved.

Some years of experience in teaching the elements of Geodesy and of Topographical Survey to the students of the Department of Geography in the University of Cambridge have shown me that there is need of a book which shall give a general account of the many-sided art of Survey. The two official military textbooks, the Textbook of Topographical Surveying, by Colonel C. F. Close, and the Manual of Map Reading and Field Sketching, are invaluable for instruction in all the vi PREFACE

details of the various processes, and there is no need to make any attempt to replace them. But it seems to me that the student needs some explanatory introduction, unobscured by much detail, which shall exhibit the general nature of the operations, and the relations to one another of the various parts of the subject.

It is certain, also, that the student of geography requires an elementary account of the operations of Geodesy proper, that is to say, of the higher survey whose aim is to contribute to the knowledge of the size and shape of the Earth ; and which has in recent years extended its enquiries into the constitution of the Earth's interior. These subjects are entirely excluded from the official books mentioned above, and I do not think that there is any book which gives a general account of this most interesting part of the subject.

The ultimate refinements of Geodesy cannot affect the maps in the slightest degree, cannot be said to be of any practical use whatever, can offer no return in cash for the money which may be, and which ought to be, spent upon them. Their justification is on a higher plane. A nation is judged, and rightly judged, by the public spirit and the public taste which it shows in its buildings, its pictures, and its gardens, which any educated man is, or thinks he is, competent to appreciate. And equally a nation is judged, though by a smaller circle of judges, for the contributions which it can make to pure knowledge. An exquisite piece of Geodesy may give as real a pleasure, and be as genuine a source of pride, as the masterpieces of art and literature.

I have made no attempt to describe the minutiae of instrumental adjustments or processes, believing that a general view of the subject should not be obstructed by a mass of detail which is tedious to read, but had better be avoided until the student comes to deal with the instruments themselves, and

PREFACE vii

carry out an actual piece of survey with them. Nor have I been able to give anything more than the slightest sketch of the large subject of cadastral survey. This is an intricate subject whose methods are to a great extent governed by the system of land registration and taxation in force in the country to be surveyed. There is a recent treatise on the subject — The Cadastral Survey of Egypt, by Captain H. G. Lyons, F.R.S., Surveyor-General — to which students may be referred if they wish to find a lucid account of the most interesting problems involved in this class of survey.

In the treatment of the topographical and geodetic survey I have tried to follow as closely as possible the principles underlying the methods employed by the Ordnance Survey, the Survey of India, and the School of Military Engineering at Chatham, to whose hospitality I owe my first introduction to the subject. I have profited also by the publications of the Geodetic Survey of South Africa, the United States Coast and Geodetic Survey, and the Survey of Egypt. Part of the charm of Geodesy is due to the general compatibility of the ideas which govern the operations of all countries, which may be traced without doubt to the influence of the International Geodetic Association, and to the benevolent authority exercised by the illustrious Director of its central bureau at Potsdam.

While the literature of Geodesy and Topographical Survey is extensive, comparatively little has been written on the subject of topographical representation on the map. The subject is new, because until the introduction of the present processes of colour printing there was not a great deal of scope for enterprise. It is still in the experimental state, as is evident from the continual change in the style of the publications issued by the principal map reproduction offices. Under these circumstances discussion and criticism are doubly interesting, and viii PRE FA CE

I have devoted more space than might seem necessary at first sight, to the detailed analysis of typical sheets produced by the leading surveys of the World. But since it is impracticable to give adequate specimens of these maps, this analysis can be effective only if the student is able to study a selection of the actual sheets. For this reason I have given the sheet numbers of good specimens, in the hope that the schools of geography who may be interested in the subject may find little difficulty r in procuring a characteristic series of maps.

By permission of the Controller of H.M. Stationery Office, and with the very kind assent and help of Colonel C. F. Close, C.M.G., R.E., Director-General of the Ordnance Survey, I am able to give in Plates I to V small specimens of the maps of the Ordnance Survey of Great Britain and Ireland. It is not possible to do justice to these maps in the small page of this book ; but I trust that these specimens are sufficient to show the high quality of the work of the Survey, and to serve as an incentive to the study of the complete sheets. I am especially indebted to Colonel Close for undertaking the complete production of these plates in the printing department of the Ordnance Survey at Southampton.

Plates VI to IX I am able to give by the kindness of Colonel Hedley, R.E., Chief of the Geographical Section of the General Staff. He has been so good as to take great interest in the choice of specimens from the wide range of maps produced by his department ; and in particular he has kindly placed at my disposal a specimen of the new edition of the beautiful map of Persia and Afghanistan which is in course of preparation. These four plates have been printed in the map reproduction department of the War Office. I owe to Colonel Hedley my sincere thanks for thus making it possible to include in my book four attractive examples of small scale maps.

PREFACE ix

The material for the plates showing instruments and methods I owe to many sources. Commandant Lucien Durand, of the nth Regiment of Artillery of the French Army, was so kind as to give me the three pictures reproduced in Plate XVII, showing the reconnaissance ladder and beacon scaffold which he introduced into the equipment of the Service Geographique de I'Arme^e. To Captain E. M. Jack, R.E., British Commissioner in the survey and delimitation of the Uganda-Congo boundary, I owe the two pictures of beacons which make Plate XVIII, and the two pictures of base measurement on Plate XIX. The two latter were given me by Captain Jack to illustrate a paper read before the Research Department of the Royal Geographical Society, and the Society has kindly lent the blocks from which this plate is printed.

The three figures of Plate XXI are taken from the Account of the Principal Triangulation of Great Britain, published by the Ordnance Survey, and those of Plate XXII from recent volumes of the Survey of India. The view of Banog mountain in Plate XXIII is from the same source.

The diagrammatic figure of the plane table used by the United States Coast Survey is borrowed from one of their official publications, and the picture of the geodetic level on Plate XXIII was given me by Messrs E. R. Watts and Sons, who make this pattern. The remaining figures are from photographs of instruments belonging to the Department of Geography of Cambridge University.

A. R. H.

Cambridge, May, 1913-