ABSTRACT
In the preliminary planning, and on site, a baseline must be established as close as possible to the longest edge of the survey area, or the longest unencumbered National Grid line (Figs. 116, 117), making allowance, if necessary, for the overlap of any distance transducer tripods if the survey is to run along the baseline. This baseline should be marked with ranging poles. If a theodolite is being used, a secondary baseline should be established at right angles to the first, again where it is possible to achieve the longest straight run compatible with the largest number of complete squares.
