Precision weak boson production cross-section measurements at LHCb

Precision measurements of weak boson production cross-sections at the Large Hadron Collider (LHC) allow the Standard Model to be tested and parton distribution funtions to be constrained. To achieve this goal an absolute precision of 2% or better is desirable on the experimental measurement. We present how such accuracy on the luminosity determination at a hadron collider is achieved in the LHCb experiment. The LHCb measurements are unique in that they combine two methods, the classical van der Meer method and a novel method based on beam-gas interactions. The impact of these precise luminosity measurements on the LHCb analyses of electroweak production measurements are presented.