a major issue not directly addressed by actmap is that for each new version of a supplier's map database all reference ids are usually reassigned by a compiling process, which destroys any correspondence with ids of previous versions. this seriously interferes with the ability to use incremental updates to generate a new version of a map database from a previous version. another issue not resolved by actmap is the inability to reference and characterize subsections of road segments (for example, curves, hills, maneuver lanes, etc.) in order to update them.