ABSTRACT
This chapter provides a broad outline of survey procedures for centre lines on the surface both for the conventional manual surveys and for the methods with the aid of photogrammetry in combination with electronic computers. The investigation surveys vary according to the type of country, and the density of population and buildings. An indication of the position of the centre line may be given in a medium scale map by outlining a few possible routes in relation to the contour or form lines. The operations before the actual photographs are taken consist of two phases, namely, the reconnaissance and the observations necessary for the horizontal and vertical coordinates of the base stations and the photo control points. The purpose of the final survey is to fix the designed centre line for the construction by or in relation to the marks already placed on the ground.
