1. An apparatus, comprising: at least one processor; at least one memory including computer program code, the memory and the computer program code configured to, working with the processor, cause the apparatus to perform at least the following: receive probe data indicative of a set of navigational signal measurements that is matched to a link segment; determine a set of measurement errors such that each measurement error of the set of measurement errors is a difference between a location indicated by the link segment and a location indicated by a navigational signal measurement of the set of navigational signal measurements; determine at least one statistical attribute of the set of measurement errors; and store an indication of the statistical attribute in map information associated with the link segment.