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

3.2.3.1 SELECTION OF STATIONS
The stations selected were ensured to be intervisible to each other, accessible and firmly pegged to the ground with wooden pegs and bottle corks carrying nail at the centre point to denote its exact point on the earth surface.
3.2.3.2 MONUMENTATION
While carrying out the survey, stations were selected along the given route at places where they could not be easily disturbed. They were placed accordingly by using pegs driven to a standard height beneath the earth’s surface and allowed the top to be covered with bottle cork and nails.

3.2.4FIELD OBSEVATION
There are various survey operations in data acquisition but this depends on the survey project at hand. The survey operations carried out for the execution of this project are:-
i.    Traversing(Angular and Linear measurement)
ii.    Profile and cross section leveling(height determination)
iii.    Detailing by tacheometry method
iv.    Curve designation and setting out
All these operations were carried out in accordance with the theoretical concept and survey rules and departmental instructions. It gives account of operation as carried out on the field to acquire all the necessary data needed for a sequent computation and plotting.
    The field operations were carried out in the following order:-
3.2.4.1    ANGULAR MEASUREMENT
These observations were carried out with the aid of theodolite instrument and its accessories .In theodolite instruments, the adjustments are of two categories they are:
(i)    Temporary adjustment and
(ii)    Permanent adjustment.
Permanent adjustment is only carried out by professionals when the instrument suffers permanent maladjustments while temporary adjustments is the adjustment carried out on every set up of the instruments, it is also known as station adjustments.  This adjustment entails:
(a)    Setting up and centering the instrument to enable the vertical axis coincide with the ground mark using plumb bob device method.
(b)    Leveling of the plate bubble to make bubble axis perpendicular to the vertical axis.
(c)    Focusing the telescope to prevent or eliminate parallax error.
Therefore, the following so – called temporary adjustment were made to the instrument before angular observations was made at each set up on the station.
The angles were observed on one zero’s as the specification given. Observations were taken at every station by sighting the target on face left and face right. Back and forward stations Observation were simultaneously carried out.
At the commencement of the angular observations, the control check was first carried out. The instrument was set on FSS2/GPS/121, one target was set on FSS2/GPS/120 and another one at FSS2/GPS/118. The Observation was made and recorded. Then, the computed data from the given coordinates was compared with the observed angle.
Having done that, the third order theodolite traverse operation was executed clockwisely along the traverse line in accordance with survey rules, regulations and departmental instructions. The traverse was finally closed on another three (3) set of controls which are FSS2/GPS/02, FSS2/GPS/03and FSS2/GPS/04. All the observations were recorded in the field book. See appendix 2
3.2.4.2LINEAR MEASUREMENTS
This measurement could be carried out by various methods depending on the accuracy expected and purpose needed. These methods are:
(i)    Tacheometric method
(ii)    Direct linear measurement method (taping on ground or catenary).
(iii)    Electronic distance measurement method