(IBS) / Electronic Charts

Capt. Taner ALBAYRAK

Electronic Chart Display

and Information

Systems

ECDIS

Objectives:

1. Become familiar with the principal types of

electronic charts.

2. Understand the difference between an ECDIS

and an ECS.

3. Understand the different Electronic Chart

formats and their advantages and

disadvantages.

Objectives: 4. Become familiar with the display characteristics of

an ECDIS System.

5. Understand the limits of an ECDIS based on the

performance limits of sensors.

6. Understand the risk of over reliance on an ECDIS

System.

Background

Electronic databases, operating systems,

computer technology and the widespread

deployment of Digital technology has made it

possible to employ electronic charts at sea.

In addition, the advent of continuous and

automated positioning systems (such as GPS),

have made it possible to take maximum

advantage of electronic charting.

The benefits of the integrated system

GPS and chart data in digital format

include:

- Real time position .

- Automated plotting of the navigation.

- Reduce Manning

- Minimizing Human error .

- Alert to navigation dangers.

- dramatically increase awareness in low

visibility.

Electronic Charting Systems

These advances in technology have made it possible to replace the traditional paper charts with Electronic Charting Systems. All electronic charting systems fall into two categories. The two categories are:

• ECDIS (Electronic Charting and Display System)

• and ECS (Electronic Charting System).

Electronic Chart Display & Information

System (ECDIS)

“means a navigation information system which, with adequate back-up arrangements, can be accepted as complying with the up-to-date chart requirements by regulation V/20 of the 1974 SOLAS Convention, by displaying selected information from a system navigational chart (SENC) with positional information from navigation sensors to assist the mariner in route planning and route monitoring, and by displaying additional navigation-related information if required.”

Sec. 2.1 IMO PS

And that means????

The short explanation: An ECDIS is a

system that is able to display electronic

chart information with automatic position

updates, contains a built in redundancy that

will assist the mariner in all aspects of

Navigation. It is the legal equivalent of a

paper chart.

It is Not an ECDIS if…..

Equipment is not legally approved.

Does not have adequate electronic chart coverage.

Does not have chart updating capability.

Even though an ECS may perform many of the same functions as an ECDIS, it is not the legal equivalent of an ECDIS. It may only be used for “situational awareness”.

What makes up an ECDIS or ECS?

1. Position inputs (GPS, DGPS, LORAN, Radar,

gyro, fathometer, etc.)

2. Electronic Navigation Charts (ENC)

3. System Electronic Navigation Charts (SENC)

Color Display

Computer AISGyrocompass

ENCDepthsounder Currents

Updates

Radar/ARPA(GPS, LORAN)Nav Sensors

Water level

Ice info

ECDIS COMPONENTS

SENC

XTD

SPD

CSE

Electronic Navigational Chart

(ENC) “Is the database, standardized as to content,

structure and format, issued for use with ECDIS on the authority of government-authorized hydrographic offices. The ENC contains all the chart information necessary for safe navigation, and may contain supplementary information in addition to that contained in the paper chart (e.g., sailing directions) which may be considered necessary for safe navigation.”

Sec. 2.2, IMO PS

So What?

An ENC is a database, not a chart as

you think of it. As such, there are:

• different types of EC data

• various formats

• differences in the level of content

System ENC (SENC)

“Is the database resulting from the transformation of the ENC by ECDIS for appropriate use, updates to the ENC by appropriate means, and other data added by the mariner. It is this database that is actually accessed by ECDIS for the display generation and other navigational functions, and is the equivalent of an up-to-date paper chart. The SENC may also contain information from other sources.”

Sec. 2.3, IMO PS

ENCENC

Data

Updates

#1

#2

#3

SENC

#1

#3

#2

+

+

+

SENC

SENC

SENC

1

2

3

IHO S-57 Performed in ECDIS

Software

IHO S-52 Colors & Symbols

Display

System Electronic Navigational Chart (SENC)

NextNext

Not all charts are equal….

• Many different formats exist for electronic charts.

• The two major types are vector based and raster charts.

• Raster charts are scanned paper charts.

• Most vector charts are digitized paper charts, thereby inheriting any errors (and possibly introducing some!)

• Countries are producing unique digital charts based on their interpretation of IHO standards.

ENC

DNC® BSB

ARCS

C-MAP

Navionics

Transas

The Types of EC Formats are:

Raster and Vector

NIMA

Digital Nautical

Chart (DNC®)

IHO S-57

Electronic

Navigational Chart

(ENC)

NOAA

Raster Nautical

Chart (RNC)

Digital Chart Formats

The Basic Difference

• Raster charts are simply bitmap images

created by scanning a paper chart

• Vector charts portray charted features as

points, lines, or areas with amplifying

information (attributes) found in an

associated database

Raster Charts

• A set of colored pixels representing chart information as a picture on computer screen

• Simply an array of pixels arranged in rows and columns

• Pixels are color coded, but do not represent features explicitly

The Appeal of Raster

• Looks like a paper chart

(appeals to traditionalists)

• Cheap and easy to produce

(scan existing paper chart)

• Runs easily on PC

• World-wide availability

Vector Charts: More detail

• A set of accurately

positioned lines (vectors),

points and areas, with

associated attributes (e.g.

“shoreline”, “buoy - red”)

organized in a database

accessed by clicking on

displayed symbol

Paradigm Shift

• Looks “different” from a

paper chart

• Underlying database allows

queries and layer selection

• Zooming reveals detail

• Complex, expensive, and

time-consuming to produce

• Needs more powerful

computer and expensive

display to meet IHO/DoD

requirements

USN Approach is to use NIMA’s Digital

Nautical Chart (DNC), a vector based format.

Some Other Examples...

Raster Chart

ECDIS Workspace (Raster Chart)

IMO/IHO

Compliant

Display

DNC with Base data only

showing (Less clutter)

Standard Display with Depth Contours

The user defines what features

are necessary!!!

Standard Display with Spot Soundings

DNC with User defined Color

All Features

NOAA BSB Vector Chart

Combined BSB and DNC display

The Advantages of Vector Charts

• Information on Chart can be linked to

specific points. (Click on light and you can

retrieve more info, like a picture of the

light)

• Allows the user to display the information

that is necessary for the ship’s current

mission.

Raster Concerns

• High scan resolution required for detailed

chart….lot’s of CPU memory required and

slower refresh rates.

• Zooming degrades quality.

• Mixed pixels—is it water or land?

Raster Model

Land

Shoreline

Water

Vector Shoreline

The State of Raster Systems

• Here to stay—most popular chart format

• Expanded capabilities:

Quilting • Multiple raster charts at multiple scales are provided • RCDS/ECS system selects largest scale chart available • Chart boundaries are zoomed to same scale, and made as

seamless possible

Overlays

• RNC provides the basic backdrop chart layer • Vector overlays - route planning and recorded track histories • (Digital) radar overlays can be displayed

Ancillary information

• Tides, currents

Radar Overlay (Raster)

Visual Bearing LOP Fix

Radar Range LOP Fix

Piloting Guidance

Automatically calculates:

• cross-track error

• recommended course to

steer accounting for

set/drift

• nearest hazard

• next navigation aid

• depth

• distance and time to turn

Military standard navigation report

Tabular turnpoint solution data

Piloting Guidance – Turn Bearings

Tide and Current Information

Displayed on the chart…

…and graphically in

pop-up windows.

Collision Avoidance

Litton Sperry VMS

•ECDIS-N system

•Part of Smart-Ship and Smart Gator

Integrated Bridge Systems (IBS)

•Supports all electronic chart types.

•Equipped with voyage planning, radar

overlay, automatic navigation and track

keeping system, voyage data recorder, and

software that estimates future position.

Radar Overlay

Future Position Estimate

The Risks of ECDIS

• ECDIS is only a tool that helps a mariner

safely and effectively navigate a ship.

• It is not the end-all be-all to ship navigation.

• One of the biggest risks with the transition

to ECDIS is an over reliance in the

information provided

Some things to consider…

• Poor GPS performance

• DGPS used/not used

• ECDIS malfunction

• installation setup

• ENC compilation errors (e.g., datums)

• chart (errors, omissions, out-dated)

• survey errors

• human error