Question $2(100$ Marks$)$

a$.$

$($i$)$ You are the surveyor for a high rise $45$ m tall. You have decided to place external ground control marks based upon an observer vertical circle depression angle of $30.$ Calculate the horizontal distance for the external control mark to be visible from the top of the building. $(10$ marks$)$

$($ii$)$ The building has an absolute position tolerance of $30$ mm in any direction. You undertook some checks for your grid to the external control points at a building height of $25$ m $.$ By grid sight hole your coordinated position is $100$ m E and $200$ m N $,$ by resection to external control points your position is $100\mathrm{.}01$ E and $199\mathrm{.}98$ N $.$ Briefly discuss why and whether you should be concerned $($or not$)(15$ marks$).$ Nominate two field measures you would undertake prior to any corrective actions, if required. $(10$ marks$)($Total $25$ marks$)$

b$.$ A surveyor is tasked to check the verticality of a four$-$story building with precast walls installed. There are reflective tapes on top of each precast wall and below observations are reduced after a couple of readings. Carry out the necessary calculations for the task and interpret the results if the given tolerance is $3$ mm $.(25$ marks$)$

Target

Zenith angle

Slope distance

Horizontal angle

$\backslash$table$[[$Wall block A$,87{15}^{\text{'}}{33}^{\text{'}\text{'}},50\mathrm{.}188m,16{12}^{\text{'}}{08}^{\text{'}\text{'}}$