# Surveying

## Abuse of terminology

- precision: consistency of repeated observations
- accuracy: the proximity of measurements to the true value

## Significant figures
- Great tutorial: https://www.youtube.com/watch?v=l2yuDvwYq5g
- (The slide is from Jagrut)

## Differential leveling
When you turn the level towards the benchmark, you are calculating what’s called a backsight. It’s opposite to the direction you’re moving hence it’s called backsight.

Getting that backsight from the level will allow us to add that number to the elevation that was already given. When we add the backlight to the elevation, we get the height of the instrument from the deep ground. Then, we turn our level to our direction (counterclockwise) and get the foresight of the next station. In order to find the elevation of the next station, we simply subtract the foresight from the height of the instrument. We continue this process for all station until we get back to the becnchmark. When we subtract the foresight of the benchmark from the foresight in the final stop, we should get the given elevation that was already provided.

## Comprehension check