Chain Survey – Use, Care, Maintenance and Common Terms
In chain surveying, proper use of instruments along with their care and maintenance is essential for accurate results and long service life. In ITI Draughtsman Civil, students must understand how to handle surveying tools correctly and be familiar with commonly used terms in the field.
1. Use of Chain Survey Instruments
The instruments used in chain surveying serve different purposes during fieldwork. Proper usage ensures accurate measurement and efficient work.
- Chain/Tape: Used for measuring distances between two points.
- Ranging Rod: Used to mark stations and align straight lines.
- Arrows: Used to count the number of chain lengths measured.
- Cross Staff/Optical Square: Used to set right angles for offsets.
- Offset Rod: Used to measure short perpendicular distances.
- Pegs: Used to mark survey stations on the ground.
- Plumb Bob: Used for vertical alignment.
- Field Book: Used to record measurements and sketches.
Proper handling of these instruments helps in reducing errors and improving efficiency in survey work.
2. Care of Surveying Instruments
Surveying instruments are delicate and must be handled carefully to maintain accuracy.
- Always clean instruments after use.
- Keep chains and tapes free from mud and moisture.
- Avoid dropping or throwing instruments.
- Store instruments in a dry and safe place.
- Protect instruments from rust and corrosion.
- Handle optical instruments carefully to avoid damage.
3. Maintenance of Instruments
Regular maintenance is necessary to keep instruments in good working condition.
- Check chain links regularly for wear and elongation.
- Oil metal parts to prevent rusting.
- Repair damaged or bent parts immediately.
- Calibrate tapes and chains periodically.
- Ensure screws and joints are tight.
4. Common Terms Used in Chain Survey
Understanding common terms is important for effective communication and accurate work in surveying.
- Survey Station: A fixed point on the ground where measurements are taken.
- Main Station: Important points forming the main framework.
- Base Line: The longest and most important line in the survey.
- Chain Line: Line along which measurements are taken.
- Offset: Perpendicular distance from the chain line to a point.
- Perpendicular Offset: Offset taken at right angles.
- Oblique Offset: Offset taken at an angle other than 90°.
- Tie Line: Line joining two points for locating details.
- Check Line: Line used to verify accuracy.
- Ranging: The process of aligning points in a straight line.
5. Importance of Proper Use and Maintenance
- Ensures accuracy in measurements.
- Increases the life of instruments.
- Reduces chances of errors.
- Improves efficiency in survey work.
Role of Draughtsman Civil
A Draughtsman Civil uses survey data to prepare plans and drawings. Proper understanding of instrument use, care, and terminology helps in interpreting field data accurately and producing precise drawings.
Conclusion
The correct use, care, and maintenance of surveying instruments are essential for successful chain surveying. Knowledge of common terms further helps in understanding and executing survey work efficiently.
For ITI Draughtsman Civil students, mastering these aspects ensures accuracy, safety, and professionalism in surveying practices.