An apparatus including a processor and memory having computer program code, the memory and computer program code configured to, with the processor, enable the apparatus at least to: use a classification model to identify one or more anomalies between a monitored trajectory of a vehicle through a road network and predefined map data for the road network which are likely caused by errors in the predefined map data; and provide details of the one or more identified anomalies for use in obtaining additional data for the specific locations on the road network corresponding to the one or more identified anomalies in order to correct the errors in the predefined map data.