Auto Level Survey

Introduction

An Auto Level Survey is a fundamental method in surveying used to determine height differences and to establish points in the same horizontal plane. It uses an Automatic Level Instrument, commonly known as an Auto Level, which provides accurate and reliable measurements for levelling tasks in construction, engineering, and land surveying.

What is an Auto Level?

An Auto Level is a precision instrument designed to maintain a horizontal line of sight automatically. It is equipped with a compensator mechanism that automatically adjusts the line of sight to be perfectly horizontal even if the instrument is slightly tilted. This feature enhances accuracy and makes it easier to use in the field.

Key Components

Telescope – For viewing distant objects clearly.
Levelling Screws – Used to level the instrument manually during setup.
Compensator – A self-levelling device that keeps the line of sight horizontal.
Circular Bubble (Spirit Level) – Helps in initial manual levelling.
Tripod Stand – To mount and stabilize the Auto Level.

Surveying Procedure

Setup – Fix the auto level on the tripod and roughly level it using the foot screws.
Levelling – Use the bubble level to ensure the instrument is levelled horizontally.
Backsight (BS) – Measure the height from a known benchmark.
Foresight (FS) – Measure the height on the next point to be determined.
Calculation – Determine the reduced level (RL) by subtracting FS from the height of instrument (HI), which is calculated from BS.
Recording – Data is noted in a levelling field book or entered into digital devices.

Applications

Establishing ground levels
Roadwork and pipeline projects
Foundation levelling
Landscape design
Drainage and irrigation layout

Advantages

Simple to use and cost-effective
High accuracy in elevation measurement
Durable and reliable for outdoor conditions
Requires minimal maintenance
Suitable for both small and large-scale projects

Conclusion

Auto Level Surveys are essential for any project requiring accurate height measurement and level determination. Their ease of use, combined with high precision, makes them a standard tool in surveying, construction, and civil engineering projects.