Is the value of `g` same every where on the surface of Earth ? How has it been decided?

Explanation

The value of `g` is differenct places on the surface of Earth. The shape of the Earth is not exactly spherical , it is flattened at the poles and is bulging out at the equator. Due to it, the radius of the Earth is smaller at poles and is larger at equator. Since, `g prop 1//R^(2)`, therefore, the acceleration due to gravity is smaller at equator than that at poles.