An apparatus comprising a processor and memory including computer program code, the memory and computer program code configured to, with the processor, enable the apparatus at least to:



generate, in respect of a road intersection, grouped probe data using probe data derived from probed vehicular movements through the road intersection, wherein the grouped probe data is generated by grouping together probe data comprising vehicle trajectories which have respective common heading angles at points of entry to and exit from the road intersection; and
provide the grouped probe data for use in lane-level mapping of the road intersection.