During the last 5 years there has been a rapid growth in the market for electronic charts. All of the systems that currently use these charts, regardless of their size and complexity, have one thing in common: they are all officially classified as Electronic Chart Systems (ECS). By definition, these systems are not considered to be equivalent to conventional paper charts for the purposes of satisfying SOLAS regulations. For all vessels bound by these regulations, ECS cannot be used in place of paper charts. Consequently, it has been left to commercial companies to provide data for use in these systems. Such data have been of variable quality, and no commercial company currently provides a correction service that matches that provided by most hydrographic offices for paper charts.