surveying iii (topographic and geodetic surveys) - Modern Prepper

From column 9: +0.232From column 4: +0.231(+0.463)/2 = + 0.232 (mean difference)Enter the following value in column 10, opposite station 4: + 0.232.a. The field computations and entries for one complete station have been entered. Make the entriesfor all other stations in a similar manner. The surveyor should be primarily concerned with the datacontained in columns 1, 2, 3, 6, and 7.b. The object of profile leveling is to find the elevations of points at known distances apart and thusobtain the profile over a given line. The profile should show the elevations of the tops of all posts alongthe baseline, as they would be seen in from the side.c. When a level is properly set up, the line of sight is perpendicular to the line of gravitation andrevolves in a horizontal plane. The line of sight is the basis for determining elevations and establishingpoints.d. In all surveys, the elevations are referred to some common datum that is designated as zeroelevation. To obtain the elevation of any point not in the datum, add or subtract the point's verticaldistance above or below that plane. When an elevation has not yet been established, an elevation(referred to as MSL, which is considered zero) simply assumes a datum and assigns an arbitraryelevation to the starting point. All level shots taken within the area are then relative to the arbitraryelevation assigned. At a later date, the assumed elevation of the starting point must be tied into abenchmark of known elevation.e. Since the lines of a scheme of triangulation are reduced to their equivalent lengths at sea level,the length of any base must be likewise reduced to sea level before it can be used in adjusting thetriangulation to which it is connected. This requires the connection of the baseline levels to a benchmarkand the computation of the elevation above sea level of the tape supports in order to obtain a meanelevation for the base. This reduction to sea level is peculiar to triangulation work and is not necessaryfor ordinary level work.3-10. Measure the Baseline. To accurately measure a baseline, all party members must function as asingle unit at the precise moment of marking. The following procedures are recommended to obtain asuccessful measurement: The rear stretcher man, the middleman, and the front stretcher man are positioned aspreviously outlined in paragraph 3-7d and e, pages 3-6 and 3-7. The rear contact man stands directly opposite the mark, which is on the copper strip nailed tothe top of the post. With one hand he firmly grasps the tape between the rear tape stretcherand the mark on the copper strip. With the other hand he lightly touches the tape on theopposite side of the3-11 EN0593