1. A method for determining the offset between at least two origins of a coordinate system used for at least two different defect inspection spaces, the method comprising: collecting multiple sets of data spanning said defect inspection spaces; filtering said data sets to remove points that introduce noise into correlation calculations; determining whether different said data sets show correlation; selecting pairs of said data sets showing correlation greater than or equal to a metric, if different said data sets show correlation; and calculating coordinate offsets of said origins based on the said selected pairs of said data sets.