Session A Flashcards
(23 cards)
What is a Spirit level used for?
Used for short distances, provides accurate horizontal levels
Spirit levels are essential tools in surveying to ensure accuracy in horizontal measurements.
What are the two types of tape measures mentioned?
Auto-retracting and reel tapes
Tape measures are commonly used for measuring distances in surveying.
What principle does a Water level operate on?
Uses the principle that water finds its own level
Water levels are often used in surveying to establish elevation differences.
What is an Automatic level?
A telescope on a tripod used with a staff to measure heights
Automatic levels enhance accuracy and efficiency in height measurements.
What is a Laser level?
Modern equipment requiring only one person to operate
Laser levels provide precise leveling over long distances.
What is a Metric staff used for?
Used to take measurements, typically with ‘E’ pattern for readability
Metric staffs are designed for easy reading of measurements in surveying.
What is a Datum?
A fixed reference point with known height (real or assumed)
Datums are crucial for establishing a baseline in surveying.
What is a Benchmark?
A fixed point of reference with known height formally recorded by surveyors
Benchmarks serve as essential reference points in surveying projects.
What does Reduced Level (RL) represent?
The ‘real level’ of a point in relation to a datum
RL is vital for understanding the elevation of points in a survey.
What is Collimation Height?
Also called ‘instrument height’ or ‘eye height’, represents the horizontal plane of view
Collimation height is key for accurate height measurements.
What is the formula for the Collimation Method to calculate Reduced Levels?
RL = Collimation Height - Staff Reading
This method provides a systematic way to establish RLs based on instrument height.
What is the formula for the Rise/Fall Method?
New RL = Previous RL + (- Difference)
The Rise/Fall Method allows for calculating changes in elevation between points.
What defines an Open Survey?
Does not close onto a known RL
Open surveys may be used in preliminary assessments where exact closure isn’t necessary.
What defines a Closed Survey?
Closes onto a known RL
Closed surveys are used for accurate measurements, ensuring reliability in data.
What is a Traverse Survey?
Uses multiple setups and change points to move across the site
Traverse surveys facilitate comprehensive site analysis by covering various points.
What does the Backsight term refer to?
The first staff reading onto a known point
Backsight readings are crucial for establishing reference points in surveys.
What is an Intermediate Sight?
Readings between backsight and foresight
Intermediate sights help provide additional data for accurate leveling.
What does Foresight mean?
The last staff reading onto the last point
Foresight readings are essential for concluding measurements in surveys.
What is a Change Point?
Where a foresight onto a point is used again from a new setup
Change points are important for maintaining continuity in surveying.
What is the Error of Closure?
The difference between the starting and ending RL in a closed traverse
Understanding the Error of Closure is vital for assessing the accuracy of a survey.
What are the two parts of the Five Peg Exercise?
- Part One - From the Middle
- Part Two - Traverse Around the Outside
The Five Peg Exercise is a practical assessment to reinforce surveying skills.
What is involved in Part One of the Five Peg Exercise?
Setting up the instrument in the middle and taking measurements to pegs around the perimeter
This part focuses on establishing RLs for each peg.
What does Part Two of the Five Peg Exercise entail?
Using multiple ‘change points’ with multiple setups to traverse the RL of peg heights around the perimeter
This part checks for errors by closing onto the datum.
