INTRODUCTION OF PLANE AND GEODETIC SURVEYING :
Engineering works such as buildings, bridges, roads, pipelines and tunnels require very precise dimensional control during their construction. Buildings must be vertical, long tunnels must end at the correct place and foundations must often be constructed in advance to accommodate prefabricated structural sections.
To achieve this, surveyors are required to determine the relative positions of fixed points to high accuracy and also to establish physical markers at (or very close to) predetermined locations. These tasks are achieved using networks of so-called control points; this book aims to give the civil engineering surveyor all the necessary the oretical knowledge to set up, manage and use such networks, for the construction and monitoring of large or small engineering works.
The exact way in which control networks are established and managed depends on a number of factors :
- The size of the construction project and the accuracy required. The accuracy of each technique described in this book is explained, together with the limitations of the various assumptions used in subsequent calculations. In particular, guidance is given as to when a project is sufficiently large that the curvature of the earth must be taken into account.
- The available equipment. As far as possible, the descriptions of surveying equipment in this book are generic and are not based on the products of any one particular manufacturer. Both GPS and ‘conventional’ surveying equipment are covered, since both are appropriate under different circumstances.
- The country in which the work is being carried out. This book explores some topics with particular reference to the mapping system used in Great Britain; but a clear indication is also given of how the same issues are addressed in other countries, with different mapping systems and survey authorities.