an ECS or ECDIS system that is capable of displaying official Raster charts (i.e. Raster charts produced by or on behalf of national HOs). When an ECDIS is displaying official Raster charts, it is in RCDS mode and can still be regarded as operating as a full ECDIS so long as there are no ENCs available of the area on display. The raster charts used in this mode do not meet the relevant SOLAS chart carriage requirements and so must be supported with an adequate folio of paper charts. Individual flag states determine the meaning of "adequate" in this context.