Essentials of AERIAL SURVEYING AND PHOTO INTERPRETATION by TALBERT ABRAMS. Originally published in 1914. PREFACE: This book combines the knowledge and experience of the members of the instructional staff of the Abrams School of Aerial Surveying and Photo Interpretation. In similar form, the material has been used in instructing men in the U. S. Marine Corps The Engineering, Science, Management, and War Training courses sponsored by the U. S. pepartment of Education and staffs of various schools and colleges. Aerial photographic mapping and reconnaissance has become a very important weapon in the Second World War. It furnishes a fast and easy means of obtaining military information concerning enemy movements and methods of attack. Approximately ninety per cent of military intelligence comes from this one source alone. Recognition of the value of aerial photographs for mapping purposes and as a source of detailed information has developed a need for specialists trained in photographic interpretation and qualified to make detailed reports on topographic information in map and chart form. This book is prepared to describe instructively present-day methods of aerial photographic interpretation and map making and the operation of modern photogrammetric equipment. It is intended to present the subject matter in its simplest and most useful form so that all can readily understand the many uses and applications of aerial photographs. Long mathematical illustrations have been reduced to simple and practical problems in arithmetic. Chapters, as well as the material in them, have been arranged in the order of difficulty in a modern handbook-textbook style. This enables the reader to understand or to refer to the elementary uses of aerial photographs before attempting the more advanced uses. This arrangement will teach the how of aerial mapping. TALBERT ABRAMS. June. 1944, Contents include: PREFACE vh CHAPTER I. MATHEMATICS, SIMPLIFIED AND ABBREVIATED I Slide Rule, Ratio and Proportion, Logarithms, Trigonom etry. II. SURVEYING 17 Introduction, Measurement of Distances, Measurement of Direction, Levels and Leveling, Plane Table Method, The Sketch Board, Triangulation. III. MAPS AND GLOBES 55 IV. MAP PROJECTIONS 58 V. ORIENTATION AND LOCATION 09 VI. TOPOGRAPHIC DRAFTING 83 Drawing Instruments, Topographic Symbols, Contours, Hasty Maps and Overlays. VII. How AERIAL PHOTOGRAPHS ARE MADE 99 Aerial Equipment, How to Find the Scale of Prints, Ver tical Photography, Oblique Photography, Laboratory Pro cedure. VIII. STEREOVISION 127 IX. INTERPRETATION 134 X. GROUND FORM LINKS 153 XI. STEREOP LOTTING INSTRUMENTS 159 Abrams Jon tour Finder, How to Operate the Multiplex Aeroprojector. XII. TOPOGRAPHIC RELIEF MODELS 186 XIII. RESTITUTION AND RECTIFICATION OF AERIAL PHOTOGRAPHS. 196 XIV...