Non‐Center Line Layout

Abstract

A line identifying some part of construction, e.g. a road centerline, is a series of line segments joining points of intersection, with intervening curves. The coordinates of each point of intersection, and the equation of each horizontal or vertical curve, defines such a line. This paper presents a procedure to compute horizontal and vertical offsets to lay out this line from points on a nearby surveyed line. Hand calculator programs are available to compute layout dimensions in the case that horizontal curves are circular, and vertical curves parabolic. Calculator programs were used in the field to permit initial survey, design and layout of drainage ditches in a remote area to be completed without leaving the site. Given the capability to compute layout dimensions to mathematically defined construction boundaries from an arbitrarily located control point, it may become feasible to automatically and remotely guide construction machinery by signals from a microprocessor‐equipped survey instrument that tracks the machinery.