What are Spherical Coordinates?

P (r, θ, φ)

r is the distance of point P from origin or radius of hypothetical sphere at origin passing through point P.

θ aka colatitude, is the minimum angle between position vector or ‘r’ of the given point and positive Z-axis.

φ is same as in cylindrical coordinate system; angle made by the half plane containing the required point with the positive X-axis.