Route Survey Of The Stretch Of Road From Oriawo Along Ogbomoso Road, Oyo To School Of Science, Sabo Oyo Town, Atiba Local Government Area, Oyo State

In this project,
Theodolite and Electronic Distance Measurement (Leica TC 600 total station) was used for traversing, and direct linear measurements respectively were used. For profile and cross section leveling, a Levelling Instrument was used.
3.2.4.3 LEVELING
Leveling is the process of determining the differences in height between points on the earth surface.
The following ground methods could be used to determine the relative height of survey points, these are:
(a)    Spirit leveling
(b)    Trigonometric leveling
(c)    Barometric leveling
The method used in carrying out the relative heighting for this project was the spirit leveling method. This operation started from a known heightened control or benchmark (FSS2/GPS/121) running through both longitudinal and cross sectional points and closed back to another benchmark (FSS2/GPS/03).
In this project, level Observations were carried out in two ways namely:
(i)    Longitudinal or profile leveling
(ii)    Cross section leveling.
Longitudinal or profile leveling: This is the operation of levels along the centre line of any proposed route such as roads, railway, etc, at regular intervals. The centre line was mark at 30m interval.
These points were heightened by means of leveling operation using a dumpy leveling and the leveling staff. The back sight was taken before the foresight.  The importance of the profile is to provide information about the difference in height of points along the centre line of the route. 
Cross section leveling: This is the operation of taken levels perpendicular to the direction of centre line of the route that is, right angle to the longitudinal section.
Cross section was needed to provide information about the ground character on either side of the longitudinal sections. The importance of this is to show any variation in ground slope on either of the centre line which could have considerable effect on the amount and type of construction work involved if details information about them were not knows. In this project, the cross sections were marked at 7.5m/7.5m offset interval from the centre line .i.e. 15m at both sides from the centre line.
Leveling started from a bench mark FSS2/GPS/121while the instrument was placed outside the line and observation was made to the bench mark at backsight while other observation were intermediate. During this observation, every change in instrument, the last observation which was the foresight became our backsight.