Nautical auxiliary and reference charts
Reference and auxiliary charts are one of the main groups of nautical charts enabling maritime users and everybody interested in sea to get a wider knowledge of the World ocean and its separate regions.
Reference and auxiliary charts are cartographic publications having different topics and designation, containing information reflected insufficiently or missing on nautical charts and which is needed for navigating conditions study.
Charts of this group are not used directly for navigation. These are auxiliary cartographic materials containing some data which contribute to solution of problems of navigational, applied and scientific nature.