This good practice guide deals with the measurement of the luminous intensity distribution (LID) of light sources using goniophotometers and its uncertainty. The aim of classic LID measurements is usually to determine a symmetrical light distribution, whereby the specified geometry is mapped onto the main axes of the luminaire, which define the so-called (A, α), (B, β) and (C, γ) plane-systems for different angles of views. The approach followed in this guide is based on the complete description of the kinematic chain of the goniophotometer from the source to the detector and vice versa, which allows in principle the rigorous determination of uncertainties.