Heighting II

Question 1

How do you set up the level? (3)

Answer 1

1) Turn the foot-screws of tribrach into its centre position
2) Place the level onto tripod head.
3) Centre circular bubble turn foot screw simultaneously in opposite directions unit the bubble is centre (the bubble will move in the direction of your left thumb moves).

Question 2

What is the basic levelling principle? (2)

Answer 2

1) Difference in staff reading between point equals difference in heights.
2) It is the points whose heights are required, location of the level is not as important.

Question 3

Define Back-sight.

Answer 3

First sighted at any set-up is the Back-sight (BS).

Question 4

Define Fore-sight.

Answer 4

Last station sighted at any set up is the foresight (FS).

Question 5

How do you ensure that the staff is vertical when levelling? (2)

Answer 5

1) Use the handheld staff bubble

2) Rock the staff through the vertical and book the lowest reading.

Question 6

What are the rules for the rise and fall method? (2)

Answer 6

1) BS>FS = rise (i.e. uphill)

2) BS

Question 7

How do you carry out a levelling?

Answer 7

Measure BS and then measure FS and then leapfrog with the level.