Abstract: In the intelligent era,nautical chart services are facing novel challenges arising from the dual trends of highly integrated functions and highly differentiated applications.Constructing a model spectrum of nautical chart services is of significant research and practical value for precisely fulfilling the diverse requirements of multi-level users.This paper systematically reviews the developmental trends of nautical chart services.Subsequently,it establishes a models spectrum for nautical chart services in the intelligent era.An in-depth analysis is conducted on the characteristics of five current mainstream chart service products,namely electronic nautical charts/nautical charts,web-based chart services,scientific data cartography,thematic marine charts,and public cartography & marine information graphics.Moreover,the paper explores the impacts of artificial intelligence technology on these service modes.The established models spectrum demonstrates a good adaptation to the user needs spectrum,facilitating effective alignment and matching between the supply and demand sides.The models spectrum offers a reasonable theoretical and application framework for the development of nautical chart services in the intelligent era.

Key words: nautical charts, electronic nautical charts, nautical tetrahedral model, web chart service, submarine topographic model, thematic charts, marine infographics