1. Measurement of Levels
Levelling is a vital component of surveying that focuses on determining heights and elevations of points on the Earth's surface. Critical technical terms are defined to aid understanding, including concepts like Mean Sea Level, Bench Mark, and Height of Instrument. Various levelling instruments and methods are discussed, along with types of errors that can occur in measurements, emphasizing the need for precision in engineering projects.
Enroll to start learning
You've not yet enrolled in this course. Please enroll for free to listen to audio lessons, classroom podcasts and take practice test.
Sections
Navigate through the learning materials and practice exercises.
What we have learnt
- Levelling is essential for determining elevations and differences in elevation for various engineering applications.
- A range of levelling instruments exists, including Dumpy, Auto, Digital, and Laser levels, each serving specific purposes with varying accuracy.
- Understanding various errors—instrumental, personal, and natural—is crucial to ensuring accuracy in levelling.
Key Concepts
- -- Bench Mark (BM)
- A point of known elevation above Mean Sea Level used as a reference in levelling work.
- -- Height of Instrument (HI)
- The elevation of the line of collimation measure used to find reduced levels (RLs) of various points.
- -- Mean Sea Level (MSL)
- The average height of the sea for all stages of the tides, used as a datum for various surveys.
- -- Rise and Fall Method
- A method in levelling where the differences in staff readings are used to determine the elevations of points by adding or subtracting the rise or fall from the previous point's elevation.
- -- Digital Level
- An advanced levelling instrument that uses digital image processing to display staff readings.
Additional Learning Materials
Supplementary resources to enhance your learning experience.