Planimeter

 

Planimeter

·       Planimeter is an instrument used in surveying to compute the area of any given plan.

·       Planimeter only needs plan drawn on the sheet to calculate area.

·       Generally, it is very difficult to determine the area of irregular plot so by using planimeter we can easily calculate the area of any shape.

 ·       The area can be obtained from the following expression

Where

M=Multiplier given in the table

N= Number of times the zero mark of the dial passes the index mark

C= The constant given in the table

FR = Final Reading

IR = Initial Reading

Zero Circle in Planimeter:

When the tracing point is moved along a circle without rotation of the wheel (ie: When the wheel slides without any change in reading) the circle is known as Zero Circle (or) Circle of correction.