Filter
Top Products
96 · Vector Chart material
Introduction to the S57 chart service from a RENC
Introduction
RENC concept is based on IHO standard S-63.
Before you can use RENC service, you have to be authorized as Customer of RENC. To be authorized you have to
contact official distributor (Chart Agent) of RENC. From a RENC you can get permits, charts and updates.
Permits
Permits are used to control the permission to use a chart. A permit in RENC security is connected to an edition.
Permits are issued as two different types
· Subscription Permit. These include updates for subsequent 12 months. It is assumed that a typical user is a
SOLAS class vessel, which is required to use up-to-date charts.
· One-Off Permit. These include only updates up to the issue date of the Permit. It is assumed that a typical user
is a non-SOLAS class vessel, which is not
required to use up-to-date charts.
Each Permit includes also the expiry date.
The expiry date of a Permit controls the ENC to SENC conversion. If the issue date of a chart or update is older or
equal to the Permit expiry date, then the system can convert an ENC into the SENC. There are no viewing time
limits as used in some other security systems such as ARCS. The user has a right to view a chart forever and more
over he has a right to convert a chart from its ENC format into the SENC forever.
A RENC can publish Permits in two different formats
· “*.pmt” format. This format does not include the applicable chart edition and does not
include applicable permit
type.
· PERMIT.TXT format. This format does include the applicable chart edition and does include applicable permit
type.
Both permit formats are fully operational, but the older “*.pmt” format creates confusion, because it cannot support
the user, when chart edition changes.
The system display warnings associated with expiry date. Examples are “will expire” warning 30 days before the
expiry date and “have expired” after the expiry date. These warning are relevant only for Subscription Permits.
Only the new PERMIT.TXT format support the system to suppress irrelevant warning associated with expiry date.
Product List
A Product List is maintained by a RENC. When you load charts using "Load By CD Catalogue", ECDIS will
automatically load Product list from the CD-ROM of a RENC. This list contains an up-to-date list of available
charts and their edition/update status in the RENC. When you load a CD-ROM from a RENC, the ECDIS checks
the issue date of the Product List. If the issue date indicates newer Product List, then it is copied into the ECDIS. If
the issue date indicates older Product List, then ECDIS shows a notice to the user that newer already loaded.
Authentication
Normally the authentication process is invisible for the user. Only if the Authentication fails, then the user gets
appropriate notice. From user point of view the Authentication is similar to CRC checksum test. If CRC checksum
test or Authentication fails then the chart is unusable.
Authentication uses private key and public key. A digital signature associated with each chart contains private key.
Public key is stored in the ECDIS and it is really public. RENC may publish a new public key. This public key will
be available as text by fax, by post, by front page of a newspaper etc. and as a text file called for example
PRIMAR.PUB. The day, when a RENC publish a new public key, will be similar milestone than the change of
millennium.