Introduction to leveling

Leveling

It is the branch of Surveying in which relative elevations of points are determined. There are following Types of Leveling

1. Ordinary leveling

It is general purpose Leveling and unless otherwise stated all types of Leveling will come into this category.

2. Reciprocal leveling

This is done when a site is unusually long, i.e. crossing the river. Sights are taken from the two banks by placing the staff on the opposite bank almost simultaneously and finding the average of apparent difference of level. This method eliminates the error due to curvature and refraction.

3. Precise leveling

This is a special type of Leveling using very precise level fitted with parallel plate micrometer and using precise staff with invar strip

This is used for establishing new bench marks and therefore is undertaken by state agencies.

4. Barometric leveling

This type of leveling is used in higher surfaces of earth like mountains.

Application of leveling

• Longitudinal Sections (L-Sections): It is done to determine the levels at given intervals along the center of level road.

• Cross Sections (X-Sections): These are the levels at a given cross section of a road or any engineering work

• Contouring

• Invert levels for sewers

• Head rooms from bridges: Staff is used in inverted position from the zero-end touching the ceiling of the bridge, the reading is entered as -ve and R.L of that position is calculated in usual manner.