Heighting III Flashcards
What is line levelling?
Exactly the same as loop levelling although you don’t finish where you started.
How do you know if your arithmetic is correct?
Sum of back sights - sum of fore sights = sum of rises -sum of falls = last reduced level - fist reduced level.
When is the rise and fall method quick?
Rise and fall method is quick in the field where lots of BS and FS have been taken and very few intermediate sights.
What does the rise and fall method lends itself well to?
Establishment of control, i.e. measuring other benchmarks.
When is the height of collimation method quick?
Where many intermediate sights have been taken, as fewer calculations.
What is a disadvantage with the height of collimation method?
The check is hard to remember and takes longer to compute.
When is line levelling used?
When you have to determine the levels of certain points of interest, e.g. manhole invert or station marker.
Why is the rise and fall method preferred?
Because it is much easier to remember the checks.
When is grid levelling useful?
When contouring an area or determining volumes
What is the grid intervals you observe between when grid levelling?
5-20m grid interval
For grid levelling what is the preferred booking method?
Height of collimation
In grid levelling where are the contours interpolated?
Between the highest points.
Why are profiles used?
To connect with linear survey projects, e.g. roads, river, railways and pipelines.
What does height determined along the profile line at constant intervals break in?
Slope and other critical positions such as junctions.
What is a line along a proposed route equal to?
Longitudinal section
