Differentiate chain survey from levelling using the knowledge you have acquired fromsurvey

Chain survey and leveling are two distinct techniques used in surveying, each with its specific purpose and methodology. Here are the key differences between chain survey and leveling:

Chain Survey:

1. Purpose: Chain survey is primarily used to measure and map small and moderately sized areas of land. It is commonly employed for topographic surveys, cadastral surveys, and mapping of features like boundaries, roads, buildings, and other objects on the ground.
2. Measurement: In chain survey, measurements are taken using a measuring chain or tape. The chain is typically made up of metal links, each measuring a specific length (e.g., 20 meters). By laying the chain along the ground, the distance between points can be measured.
3. Instruments: The main instrument used in chain survey is the chain or measuring tape. Additional tools such as ranging rods, compass, and theodolite may be used for angular measurements and orientation.
4. Technique: Chain survey involves a series of linear measurements between points on the ground, forming a chain of connected lines. Angles and offsets may also be measured to account for features that cannot be measured directly. The data collected is used to create a plan or map of the surveyed area.
5. Accuracy: Chain survey is generally less accurate compared to other surveying methods, such as GPS or total station surveying. The accuracy depends on the precision of the measuring chain, skill of the surveyor, and environmental conditions during the survey.

Leveling:

1. Purpose: Leveling is primarily used to determine and establish elevations or heights of points on the ground. It is commonly employed for creating contour maps, determining height differences, setting benchmarks, and ensuring level surfaces for construction projects.
2. Measurement: Leveling measurements are taken using a leveling instrument, such as a spirit level or an automatic level. The instrument measures the vertical distance or height differences between points using a leveling rod and a staff held vertically at each point.
3. Instruments: The main instrument used in leveling is the leveling instrument, which can be a simple spirit level or a more precise automatic level. A leveling rod or staff is used to measure the vertical distances, and a tripod is used to support and stabilize the instrument.
4. Technique: Leveling involves a series of vertical measurements between points, with each measurement providing the difference in height or elevation between the two points. These height differences are used to create contour lines or establish benchmark elevations.
5. Accuracy: Leveling is a more precise technique compared to chain survey. The accuracy depends on the precision and calibration of the leveling instrument, the skill of the surveyor, and factors such as atmospheric conditions and instrument setup.

In summary, chain survey is focused on measuring distances and creating plans or maps of the surveyed area, while leveling is primarily concerned with determining elevations and establishing height differences between points. Chain survey relies on linear measurements using a chain or tape, while leveling utilizes vertical measurements using a leveling instrument.