Vector Charts; S57 Charts; Introduction - Furuno FCR-2107 Operator's Manual

7. Vector Charts

Theoretically a chart can be coded for use on a computer as a vector chart. Vector-coded charts are coded using a
variety of techniques. One technique is called S57ed3 and it has been chosen by IMO as the only alternative for
SOLAS compliant electronic charts. If an S57ed3-coded chart is published by a government-authorised
Hydrographic Office, then it is called "ENC". You can read more about ENC and related legal issues in this chapter.
Hereafter, all references to vector chart material are referred to as "S57 charts" regardless of their source.
Sometimes you can wish to manually add Notices to Mariners or Navtex warnings into your S57 charts. This is
called "manual updates". Also, manual updates are valid for all scales so that you don't need to repeat them for
charts published in different scales from the same area. For further details, see Chapter 8 Manual Updates.
7.1

S57 Charts

7.1.1

Introduction

An ENC could be encrypted to prevent unauthorised use so the user needs a permit to view the ENC. This permit
could be entered manually from the control unit, loaded from a floppy disk or loaded through telecommunications
from an RENC.
Before any ENC can be used in the chart radar, it is loaded into your hard disk and converted into the system's own
internal format (SENC). Some parts of the charts may be date dependent, i.e., they are visible after a set date or they
are visible only for a limited period, etc. In the electronic chart system, you control all date-dependent objects with
Display Until and Approve Until dates. In the paper chart world, the Preliminary and Temporary Notices to
Mariners represent the date dependency described above for S57 charts.
An important part of ENCs are the updates. Hydrographic Offices can issue two kinds of updates:
1. Incremental updates, which are small additions to original base cells.
2. Reissues and new editions, which are complete replacements of previous base cells and their updates.
All updates are date stamped and they may also contain date-dependent parts. You control usage of updates in the
electronic chart system from Display Until and Approve Until dates. Using Display Until and Approve Until dates,
you can view your charts correctly drawn on any date in the past or in the future.
Chart material will be stored in media such as CD ROMs and floppies, electronically through telecommunications
from RENCs or electronically from LAN (Local Area Network) in which it could have arrived from RENCs, CD
ROMs or floppies. Such material can contain only basic cells, cells and updates or only updates. The electronic chart
system contains as standard the software required to access CD ROMs, floppies and LAN.
7-1