What is ECDIS?
The following data can be shown on a single ECDIS display screen:
- Nautical chart
- Extracts from Sailing Directions, German List of Radio Signals, and
List of Lights
- Radar overlay, ARPA targets
- Course line and present position of own ship
- Alphanumerical position and navigational data (planned routes, current
navigational data, recorded track information
- AIS symbols (Automatic Identification System)
Time-consuming manual chart correction on board the vessel is no longer necessary.
The updates are read into the system and automatically correct the ECDIS database.
The position of one's own vessel is determined by navigation systems like (D)
GPS or LORAN-C, which are interfaced with ECDIS. The vessel position is continuously
shown on the chart display, and the data is stored at regular intervals. The
chart section displayed moves along with the ship's position, at least 25 percent
of the chart display showing the area directly ahead of the vessel. Manual chart
replacement is no longer necessary. Safe track keeping is ensured by checking
against ECDIS waypoints and leglines.
Automated Radar Plotting Aid
The ECDIS display can be superimposed
with the ARPA (Automated Radar Plotting Aid) radar image and radar targets.
In this way, also the movements of other vessels can be continually monitored
on a single display screen. ECDIS has stored the vessel's draught data and "knows"
whether it is safe for her to pass through a particular area. It sounds an alarm
if, e.g., her approach to the 10-metre contour line poses a risk. ECDIS "knows"
the properties of all objects and helps to avoid dangerous close quarters situations.
To fully use the potential of ECDIS, vector charts have to be used. Vector
data are used primarily in ECDIS. But official vector data are not yet available
for all ocean areas worldwide. In the areas which are not covered with vector
data , ECDIS can switch to raster data such as ARCS (Admiralty Raster Chart
They are available worldwide
ARCS data are scanned official UK
nautical charts. They are available worldwide. Raster charts are digital reproductions
of paper charts. Because of their pixel structure they are only capable of providing
2D information and there is no direct object reference. Alphanumerical data
for the individual objects thus is missing completely. Raster charts (RNC -
Raster Nautical Chart) are georeferenced, allowing vessels to determine their
position and perform route planning. However, it is not possible for a raster system (RCDS -Raster Chart Display
System) to identify danger situations.