Area can be calculated using formulas for triangle or coordinates

Area from coordinates

Planimeter : mechanical instrument specifilcally designed to calculate irregular areas from plans and maps.

If there are n offsets

For n offsets

Preference should be given to Simpson. In cases where offsets are even numbers, partly calculate using Simpson (up to odd offsets) and trapezoidal for the remaining offsets

the reduced levels of these
points are determined determined using any suitable suitable method

reduced levels of points that lie to the left and right of the centre line at right angle are also observed, thus, creating cross‐sections

Setting‐out of roads, highways, railway track, etc., are normally done at regular intervals along the centre line

Example ‐ cutting and filling of earth for basement (car park), underground water tanks, to obtain required formation levels, etc

The difference between the grid heights and the proposed heights are obtained in order to estimate volumes

Suitable to be used when large volume is involved, such as, volumes of water contained in a dam, soil such as, volumes of water contained in a dam, soil

The area of a contour contour surface surface is determined determined. The contour’s surface can be treated as a cross‐section whose areas can be calculated either graphically or mechanically