This chapter will give you an
introduction to the various electronic
chart display systems offered to the
maritime industry giving their
advantages and disadvantages as seen
from the navigators point of view the
IMO accepted definition of an electronic
chart display equipment abbreviated ecd
IE is the display equipment that
processes and indicates necessary
information compiled in enc and other
information to assist in safe navigation
the IMO accepted definition of an
electronic chart display system
abbreviated actus is a system of the
displays hydrographic information which
may be combined with information
provided by electronic position fixing
systems GPS radar etc to assist in the
safe navigation of the vessel an
activist consists of the electronic
navigational chart as a data file and
the electronic chart display equipment
hardware
this is the definition of a system which
shows or integrates on one display where
we earlier have separated it into three
different places on the bridge of a ship
to chart the position and the radar in
addition activist is a system which can
also store and use information from
lists of lights sailing directions tide
tables etc together with the chart that
is the reason why iho defines actress as
electronic chart display and information
system
ecs is a generic term for equipment
which displays electronic charts but
which does not and will not satisfy the
soloist convention ecs cannot be used as
a substitute for official paper charts
and an up-to-date paper chart must
therefore be available examples of ecs
include radar systems incorporating
video maps standalone video plotters and
all current commercial rusted chart and
vector chart display systems i made the
decision in June 98 that rested chart
display systems rcds should be operated
together with an appropriate folio of
up-to-date paper charts later
discussions between I'm oh and iho led
to the conclusion that rust the charts
should be viewed as a simplified mode 4x
equipment the rest of chart standard
should form a part of the actors
performance standards where it would
logically fit arrest the chart should
only be used when a vector type chart
required for normal like this operation
is not available
some of the most obvious advantages of
activists are at any time it shows the
ship's position on the chart in
trumotion with or without radar overlay
and our integration in one display it
only uses the chart information
necessary for safe navigation it updates
the chart by satellite and thereby
increases the speed of updating
automatic chart updating simple voyage
planning auntie grounding warning tied
corrected depth contour blackbox
possibility storing the ship's
navigation data for a certain period
gives detailed information about lights
boys beacons etc by pointing on the
chart symbol very the chart scale
according to navigation conditions vary
the chart colors depending on day or
night navigation
show the ship in true size in narrow and
difficult areas and conditions
advantages of vector charts are many
here are some chart information is
stored in layers users may customize
chart displays to suit the particular
needs of their vessels the child data is
seamless it is possible to zoom in
without distorting the charted data it
is possible to select a safety dep and a
safety contour alarms are indications
can be given when own ship is expected
to cross safety contour or to enter a
specified area it is possible to
interrogate charted objects for further
information file sizes are up to 10
times smaller four-vector charts and
harass the charts vector charts can
generally be displayed more quickly than
rusty charts a larger color palette is
available for vector charts and for
paper or roster charts box maybe show
using different symbols to those used on
paper or roster charts charts may be
rotated to any angle course up
referenced charts may be shared with
other equipment such as radar and r /
the main disadvantages of vector charts
are vector charts are technically far
more complex than raster charts vector
charts take longer and cost more to
produce than rust the charts significant
worldwide coverage will not be provided
by official vector charts for many years
training in the use of vector charts is
likely to be longer and more costly than
that for us the charts is significantly
more difficult to ensure the quality and
integrity of the displayed vector data
the main advantages arrest the charts
are they are direct and exact copies of
existing paper charts they use the same
familiar colors and symbols as paper
charts their contents are as
comprehensive accurate and reliable as
those of paper charts it is not possible
for users to inadvertently amit
significant navigational information
from the chart display as the rest the
charts are produced from components used
in the production of paper charts both
versions can be kept in step rusty
charts are simpler and easier to produce
and update an official iho compliant
vector charts it is much easier to
ensure the quality and integrity of the
display data they cost less to produce
officially produced rusted charts are
widely available for example arcs can
now provide worldwide coverage edition
from other nautical publications may be
displayed in the same raster format with
the addition of vector overlays and
suitable software it is possible to use
rusty charts for all the standard
navigational tasks normally carried out
with paper charts and to emulate some of
the functions of activist some of the
disadvantages of rusty charts are in the
display cannot be customized when roster
charts are overlaid with other
information the display may appear
cluttered rest the charts cannot
directly provide alarms or indications
to show that own ship is expected to
cross a safety contour or to enter a
specified area raster charts cannot be
interrogated without some form of
additional database with a common
reference system rest of charts cannot
be sensibly rotated to head up or other
orientations roster charts have larger
memory
requirements than vector charts the IMO
performance standards for actus were
developed in cooperation with the
international hydrographic organization
iho and the international
electrotechnical commission IEC the iho
has developed complimentary
recommendations on electronic navigation
charts which standardize the database
and the content structure and format of
the information provided and displayed
the IEC is developing the methods of
testing and activist so it meets the
requirements from I'm oh and IEC