Contouring
Contouring is the method used for locating points on the ground by distance measurement and finding their elevations using a level. It involves the process of determining the contours, or lines of equal elevation, on a topographic map or survey. Contour lines connect points of equal elevation, allowing for visualization of the shape and slope of the land.

Process
The process of contouring involves the following steps:

1. Establishing Control Points: Control points are established at known elevations using a leveling instrument. These control points serve as reference points for subsequent elevation measurements.

2. Setting Up the Leveling Instrument: The leveling instrument, typically a level or an automatic level, is set up at a known elevation point. This instrument consists of a telescope mounted on a tripod and is used to measure the height difference between a reference point and the points being surveyed.

3. Taking Leveling Readings: The level is sighted on a benchmark or control point with a known elevation, and a leveling rod is held at the point being surveyed. The height difference between the benchmark and the point is recorded as a leveling reading.

4. Calculating Elevations: The elevation of each point is calculated by adding or subtracting the height differences recorded during the leveling readings from the known elevation of the benchmark. This process is repeated for all the points being surveyed.

5. Plotting Contour Lines: Once the elevations of the surveyed points are determined, contour lines are plotted on a topographic map. Contour lines are drawn to connect points of equal elevation, and the interval between contour lines represents a specific change in elevation.

Applications
Contouring is widely used in various fields, including:

1. Land Surveying: Contouring is essential in land surveying to determine the shape and slope of the land. It helps in designing roads, railways, buildings, and other infrastructure projects.

2. Environmental Planning: Contour maps are used in environmental planning to identify areas prone to flooding, erosion, or other natural hazards. They aid in the development of effective land-use plans and conservation strategies.

3. Civil Engineering: Contouring is crucial in civil engineering projects such as dam construction, reservoir planning, and slope stability analysis. It helps in optimizing the design and ensuring the safety of structures.

4. Urban Planning: Contour maps assist urban planners in understanding the topography and terrain of a city or region. They help in determining suitable locations for development, identifying areas for parks or open spaces, and managing stormwater runoff.

In conclusion, contouring is a method used in civil engineering and land surveying to locate points on the ground by distance measurement and determine their elevations using a level. It plays a vital role in various applications and helps in understanding and analyzing the features of the land.