Types of Levelling Instruments
Levelling instruments are used in surveying to determine the difference in elevation between points. These instruments provide a horizontal line of sight and are essential for accurate levelling work. For ITI Surveyor trainees, understanding the different types of levelling instruments is important for selecting the right tool for fieldwork.
Levelling Instruments
Levelling instruments consist of a telescope, level tube, and supporting structure. They are mounted on a tripod and used along with a levelling staff to measure heights.
Main Types of Levelling Instruments
1. Dumpy Level
Dumpy level is a commonly used levelling instrument in which the telescope is rigidly fixed to its supports.
- Simple and robust design
- Provides high accuracy
- Requires careful leveling
2. Wye (Y) Level
In this type, the telescope is supported in Y-shaped supports and can be removed and reversed.
- Easy to adjust and repair
- Less stable compared to dumpy level
3. Tilting Level
The telescope can be tilted slightly using a screw to bring the bubble to the center.
- Quick leveling
- Less accurate than dumpy level
4. Automatic Level (Auto Level)
This modern instrument uses a compensator to maintain a horizontal line of sight automatically.
- Easy to use
- High accuracy
- Saves time
5. Digital Level
A digital level provides readings electronically using a barcode staff.
- Very high accuracy
- Reduces human error
- Displays readings digitally
Comparison of Levelling Instruments
| Instrument | Accuracy | Ease of Use |
|---|---|---|
| Dumpy Level | High | Moderate |
| Wye Level | Moderate | Moderate |
| Tilting Level | Moderate | Easy |
| Auto Level | High | Very Easy |
| Digital Level | Very High | Very Easy |
Advantages of Modern Instruments
- Improved accuracy
- Faster operation
- Less manual adjustment
- Reduced chances of error
Precautions While Using Levelling Instruments
- Ensure proper leveling of instrument
- Handle instruments carefully
- Keep instruments clean and dry
- Check calibration regularly
- Avoid shocks and vibrations
Importance in Surveyor Trade
Different levelling instruments are used based on the accuracy and type of work required. Understanding these instruments helps surveyors perform accurate and efficient levelling operations.
Conclusion
Levelling instruments are essential tools in surveying for measuring elevations. From traditional dumpy levels to modern digital levels, each type has its own advantages and applications.
For ITI Surveyor trainees, knowledge of these instruments is important for selecting the appropriate equipment and achieving accurate results in the field.