sug514 - hydrographic surveying - topo map vs navigation chart, enc & ecdis

MARA UNIVERSITY OF TECHNOLOGY Jack Ruzaini BACHELOR OF GEOMATIC AND SURVEYING SCIENCE (AP220) ([email protected]) HYDROGRAPHIC SURVEYING (SUG514) Topographic Maps vs Nautical Charts, ENC & ECDIS _________________________________________________________________________________________________________

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1.0 INTRODUCTION

What Is A Nautical Chart? A nautical chart is a graphic representation of a maritime area and coastal

regions. Nautical charts are essential tools for marine navigation which many countries require vessels,

especially commercial ships, to carry them. Nautical charts may take in form of charts printed on paper or

computerised electronic navigational charts.

Nautical charts and maps serve distinctive purposes. Knowing these differences are key to safe marine

navigational practices.

So, we were given a task to investigates what the differences between the nautical charts and

topographic maps. The criteria that we have compared were such like colours, symbolisation, legends

and so on.

Besides we also made a coverage about the Electronic Chart Display and Information System (ECDIS)

and its relation to Electronic Navigational Chart (ENC).


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2.0 TOPOGRAPHIC MAPS VERSUS NAUTICAL OR NAVIGATIONAL CHARTS

Topographic Maps Navigational Charts

“A map emphasizes land forms, including the

representation of relief, with shoreline represented

as an approximate delineation usually at mean sea

level.

A map is a static document which serves as a

reference guide. A map is not, and cannot be used

to plot a course. Rather it provides a predetermined

course, usually a road, path, etc., to be followed.

Special consideration for the type of vehicle is

rarely a consideration. Further, maps provide

predetermined points-road intersections-to allow

one a choice to change to another predetermined

direction

Maps merely indicate a surface path providing no

information of the condition of the road. For

instance a map will not provide information on

whether the road is under repair (except when it is

a new road) or how many pot holes or other

obstructions it may contain. However the driver is

able to make a visual assessment of such

conditions.” [1]

“A chart, especially a nautical chart, has special

unique characteristics including a very detailed and

accurate representation of the coastline, which

takes into account varying tidal levels and water

forms, critical to a navigator.

A chart is a working document. It is used to plot

courses for navigators to follow in order to transit a

certain area It takes into account special conditions

required for one's vessel, such as draft, bottom

clearance, wrecks and obstructions which can be

hazardous. Way points are identified to indicate

relative position and points at which specific

maneuver such as

changing courses, must be performed.

Charts provide detailed information on the area

beneath the water surface, normally not visible to

the naked eye, which can and is very critical for the

safe and efficient navigation.” [1]

1. “Differences Between Maps and Charts”, http://www.nauticalcharts.noaa.gov/mcd/learn_diff_map_chart.html


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Diagram : Example

of Topographic

Maps

Diagram :

Example of

Nautical Chart


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2.1 DIFFERENCES OF LEGEND BETWEEN NAUTICAL CHART AND TOPOGRAPHIC MAP

NAVIGATION CHART LEGEND TOPOGRAPHIC MAP LEGEND


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2.2 DIFFERENCES OF SYMBOL BETWEEN NAUTICAL CHART AND TOPOGRAPHIC MAP

The example of Symbol in Nautical Chart The example of Symbol in Topographic Map

2.3 DIFFERENCES THE USE OF COLOUR BETWEEN NAUTICAL CHART AND TOPOGRAPHIC

MAP

NAUTICAL CHART TOPOGRAPHIC MAP

• sandy areas and rocks (green)

• Lighthouses and other navigation lights

(black dots with purple)

• vegetation (green)

• water (blue)

• densely built-up areas

(gray or red)

• black for cultural (man-made) features

other than roads

• topographic contours (brown)


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2.4 BASIC ELEMENTS OF NAUTICAL CHART


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1. Chart number in national chart series

2. Identification of a latticed chart (if any):

• D for Decca, LC for Loran-C, Om for Omega

3. Chart number in international chart series (if any)

4. Publication note (imprint)

5. Bar Code and Stock number

6. Edition note. In the example: Seventh edition published in June 1996

7. Source data diagram (if any). For attention to navigators: use caution where surveys are

inadequate

8. Dimensions of inner borders

9. Corner coordinates

10. Chart title (may be quoted when ordering a chart, in addition to chart number)

11. Explanatory notes on chart construction, etc. (to be read before using chart)

12. Seals: In the example, the national and International Hydrographic Organization seals show that

this national chart is also an international one. Purely national charts have the national seal only.

Reproductions of charts of other nations (facsimile) have the seals of the original producer (left),

publisher (center) and the IHO (right).

13. Projection and scale of chart at stated latitude. The scale is precisely as stated only at the latitude

quoted.

14. Linear scale on large-scale charts

15. Reference to a larger-scale chart

16. Cautionary notes (if any). Information on particular features, to be read before using chart

17. Reference to an adjoining chart of similar scale.


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2.5 DETAILS ON NAUTICAL CHART

2.5.1 PILOTAGE INFORMATION

The chart uses symbols to provide

pilotage information about the nature

and position of features useful to

navigators, such as sea bed information,

sea marks and landmarks. Some

symbols describe the sea bed with

information such as its depth, materials

as well as possible hazards such as

shipwrecks. Other symbols show the

position and characteristics of buoys,

lights, lighthouses, coastal and land features and structures that are useful for position fixing.

Colours distinguish between man-made features, dry land, seabed that dries with the tide and

seabed that is permanently underwater and indicate water depth.

2.4.2 DEPTHS

Use of colour in

charts Depths which

have been measured

are indicated by the

numbers shown on

the chart. Depths on

charts published in

most parts of the

world use metres.

Older charts, as well

as those published by the United States government, may use feet or fathoms. Depth contour

lines show the shape of underwater relief. Coloured areas of the sea emphasise shallow water

and dangerous underwater obstructions. Depths are measured from the chart datum, which will

be stated on the chart; this is often the depth of the lowest tide caused by gravity alone which is

known as the "Lowest Astronomical Tide".


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2.4.3 TIDAL INFORMATION

Tidal races and other strong currents have special chart symbols. Tidal flow information may be

shown on charts using tidal diamonds, indicating the speed and bearing of the tidal flow during

each hour of the tidal cycle.

2.4.4 SHORELINE

The shoreline shown on nautical charts represents the line of contact between the land and water

at a selected vertical datum. In areas affected by tidal fluctuations, this is usually the mean high-

water line. In confined coastal waters of diminished tidal influence, a mean water level line may

be used. The shoreline of interior waters (rivers, lakes) is usually a line representing a specified

elevation above a selected datum. A shoreline is symbolized by a heavy line. A broken line

indicates that the charted position is approximate only. The nature of the shore may be indicated.

If the low water line differs

considerably from the high water line,

then a dotted line represents the low

water line. If the bottom in this area is

composed of mud, sand, gravel or

stones, the type of material will be

indicated. If the bottom is composed of

coral or rock, then the appropriate

symbol will be used. The area

alternately covered and uncovered may be shown by a tint which is usually a combination of the

land and water tint.

The apparent shoreline shows the outer edge of marine vegetation where that limit would appear

as shoreline to the mariner. It is also used to indicate where marine vegetation prevents the

mariner from defining the shoreline. A light line symbolizes this shoreline. A broken line marks the

inner edge when no other symbol (such as a cliff or levee) furnishes such a limit. The combined

land-water tint or the land tint marks the area between inner and outer limits.


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2.5 TYPES OF SCALES AND PROJECTION

The scale of a chart is the ratio of a given distance on the chart to the actual distance which it represents

on the earth. It may be expressed in various ways. The most common are:

1. A simple ratio or fraction, known as the representative fraction. For example,

1:80,000 or 1/80,000 means that one unit (such as a meter) on the chart represents

80,000 of the same unit on the surface of the earth. This scale is sometimes called

the natural or fractional scale.

2. A statement that a given distance on the earth equals a given measure on the chart,

or vice versa. For example, “30 miles to the inch” means that 1 inch on the chart

represents 30 miles of the earth’s surface. Similarly, “2 inches to a mile” indicates

that 2 inches on the chart represent 1 mile on the earth. This is sometimes called the

numerical scale.

3. A line or bar called a graphic scale may be drawn at a convenient place on the

chart and subdivided into nautical miles, meters, etc.

A chart covering a relatively large area is called a small-scale chart and one covering a

relatively small area is called a large-scale chart.

As scale decreases, the amount of detail which can be shown decreases also. Cartographers selectively

decrease the detail in a process called generalization when producing small scale charts using large

scale charts as sources. The amount of detail shown depends on several factors, among them the

coverage of the area at larger scales and the intended use of the chart.


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The Mercator projection is almost universally used in nautical charts. There are however some

exceptions for very large or small scales where projections such as the gnomonic projection may be

used. Since the Mercator projection is conformal, that is, bearings in the chart are identical to the

corresponding angles in nature, bearings may be measured from the chart to be used at sea or plotted on

the chart from measurements taken at sea.

Positions of places shown on the chart can be measured from the longitude and latitude scales on the

borders of the chart, relative to a map datum such as WGS 84.

A bearing is the angle between the line joining the two points of interest and the line from one of the

points to the north, such as a ship’s course or a compass reading to a landmark. On nautical charts, the

top of the chart is always true north, rather than magnetic north, towards which a magnetic

compass points. Most charts include a compass rose depicting the variation between magnetic and true

north.


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2.6 SOURCES INFORMATION ON NAUTICAL CHART (Based on an example of NOAA Chart)

The nautical chart conveys a wealth of information to the mariner. The graphic below illustrates a sample

of the type of information that appears on nautical charts.

1. Floating aids to navigation established and maintained by the U.S. Coast Guard mark channels

and other features such as wrecks and obstructions.

2. The U.S. Army Corps of Engineers dredges channels so that deep draft vessels can transit into

and out of ports. Mariners must know the position and depth of these channels.

3. Nautical charts delineate the location of anchorages for military, commercial, and recreational

vessels.

4. NOAA shows official geographic names in conformance with the U.S. Board of Geographic

Names.

5. Fixed aids to navigation , such as lighthouses maintained by the U.S. Coast Guard, help

mariners navigate safely.

6. Mariners need to know bottom characteristics in order to determine where adequate holding

grounds for anchoring are located.

7. Depths determined by NOAA surveys are critical to safety of navigation.


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8. Mariners must know where underwater hazards and obstructions are located. The chart shows

the precise position and depth of water over the obstruction.

9. Most commercial ships entering a harbor need to know where pilotage areas are located. These

areas are used for taking on and leaving off marine pilots.

10. Mariners need to know the position and depths of dangerous wrecks , so they can lay out a

track to avoid these features.

11. Wire drag cleared depths show the safe navigation depth. This charting symbol indicates that

there was at least 20 feet of depth available over the top of the obstruction located here.

2.7 BOTTOM FEATURES ON NAUTICAL CHART


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3.0 ELECTRONIC CHART DISPLAY AND INFORMATION SYSTEM AND ELECTRONIC

NAVIGATIONAL CHART

3.1 DEFINITIONS OF ECDIS

“An Electronic Chart Display and Information System (ECDIS) is a computer-based navigation information

system that complies with International Maritime Organization (IMO) regulations and can be used as an

alternative to paper nautical charts.” [1]

“ Electronic Chart Display and 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 required by

regulation V/20 of the 1974 SOLAS Convention, by displaying selected information from a system

electronic navigational chart (SENC) with positional information from navigation sensors to assist the

mariner in route planning and route monitoring, and if required display additional navigation-related

information.” [2]

1. Electronic Chart Display and Information System at Wikipedia http://en.wikipedia.org/wiki/ECDIS

2. ECDIS Definitions in PERFORMANCE STANDARDS FOR ELECTRONIC CHART DISPLAY AND INFORMATION

SYSTEMS (ECDIS) [IMO Resolutions A.817 (19), MSC.64 (67) and MSC.86 (70)] (amended March 1999)


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3.2 ECDIS IN STANDARDS AND REGULATIONS

3.2.1 SOLAS 1974 [3]

Paragraph 2.1.4 of Regulation V/19 states that:

“All ships, irrespective of size, shall have:

Nautical charts and nautical publications……… to plan and display the positions throughout the

voyage; ………. An ECDIS may be accepted as meeting the chart carriage requirements of this

subparagraph…”

Convention ships may be fitted with an ECDIS system with a back-up system (either an electronic

back-up system or with appropriate paper charts for the intended voyage).

3.2.2 STCW 95 [4]

An officer who is in charge of a navigational watch on board a ship of 500 gross register

tonnage (GRT) or more should attained the minimum standard of competence specified in

Table AII/1 of STCW Code. The competence includes “Plan and conduct a passage and

determine position” of the vessel, in which he should have thorough knowledge of and ability

to use navigational charts and publications, notice to mariners (NTM), radio navigational

warnings and ships’ routing information. Note: ECDIS systems are considered to be included

under the term “charts”.

3.2.3 INTERNATIONAL STANDARDS

There are a number of International Standards which ECDIS shall meet:

• International Hydrographic Organization (IHO) [5]

transfer Standard for Digital Hydrographic

Data S- 57 [6]

,

• IHO Specifications for Chart Content and Display aspects of ECDIS S- 52 [7]

,

• IMO Resolution A.817 (19) Performance Standards for ECDIS [8]

3.2.4 IMO RESOLUTION A.817 (19) – PERFORMANCE STANDARD FOR ECDIS

Some of the requirements stated in the Performance Standards for ECDIS are as following: -

1. ECDIS should have adequate back-up arrangements (Duplication of the system or carriage

of appropriate paper charts for the intended voyage);

2. ECDIS should be capable of displaying all chart information necessary for safe and efficient

navigation;

3. ECDIS should facilitate simple and reliable updating of the electronic navigational chart;

4. ECDIS should reduce the navigational workload compared to using the paper chart;


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5. ECDIS should have at least the same reliability and availability of presentation as the paper

chart;

6. ECDIS should provide appropriate alarms or indications with respect to the information

displayed or malfunction of the equipment.

The ECDIS enables the user to call up information on the items displayed in addition to the

graphics presentation. For example, a lighthouse is marked on the chart by a tower symbol or a

traditional chart symbol if the user prefers. The system can give further information on this subject

about the characteristic and detail of the lighthouse similar to the information printed in the List of

Lights.

3.2.5 RESOLUTION MSC. 232(82) [9]

The Annex 24 of the resolution - The Revised Performance Standards For Electronic Chart

Display and Information Systems (ECDIS) which the Raster Chart Display System (RCDS or

ECD) [10]

using Raster Navigational Charts (RNC) [11]

is incorporated in the Standards to meet the

real situation.

3. SOLAS 1974 - is a safety treaty amended during the Convention of 1974 by The International Convention for Safety

of Life at Sea (SOLAS) which is an international maritime safety treaty.

4. STCW 95 - is The International Convention on Standards of Training, Certification and Watchkeeping for Seafarers

as amended a sets of qualification standards for masters, officers and watch personnel on seagoing merchant ships

in the Convention of International Maritime Organization (IMO), London 1995.

5. IHO – is an authoritative worldwide hydrographic body engages all national hydrographic offices around the world

and sets an uniformly hydrographic standards in the surveys, nautical charts, and publications which to be agreed

upon by the member nations.

6. S-57 – is the IHO Transfer Standard for Hydrographic Data, edition 3 Nov 1996. It describes the data structure and

format to be used for the exchange of ENC (Electronic Navigational Chart) data between Hydrographic Offices,

ECDIS manufacturers, mariners and other users.

7. S-52 – is the Specification for Chart Content and Display Aspects of ECDIS, edition 5 Dec 1996. It provides

specifications and guidance regarding the issue, updating and display of ENC in ECDIS.

8. IMO RESOLUTION A.817 (19) – is the IMO Performance Standards for ECDIS. It describes the minimum

performance standards for ECDIS with reference to both hardware and software, ENC and updates, user interface

and the integration of external devices.

9. RESOLUTION MSC. 232(82) – is the IMO Maritime Safety Committee Resolution which is adoption of the revised

performance standards for electronic chart display and information systems (ECDIS)

10. Raster Chart Display Systems (RCDS) – is a system that reproduce exactly the familiar paper chart. RCDS adds real

time positioning, electronic tools for voyage planning and monitoring, improved night time visibility, access to chart

notes, etc. In addition, RCDS provides for the automatic application of official updates issued by national

hydrographic offices.

11. Raster Navigational Charts (RNC) – is geo referenced navigational charts which can display vessel’s position on the

chart image if it has computer based navigation system that is connected to GPS. Its updated weekly according to

the IHO standard S-61


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3.3 ECDIS & ENC

3.3.1 DEFINITIONS OF ENC

“An electronic navigational chart (ENC) is

an official database created by a national

hydrographic office for use with an

Electronic Chart Display and Information

System (ECDIS). An electronic chart

must conform to standards stated in the

International Hydrographic Organization

(IHO) Special Publication S-57 before it can

be certified as an ENC. Only ENCs can be used in ECDIS to meet the International Maritime

Organization (IMO) performance standard for ECDIS.” [12]

“Electronic Navigational Chart (ENC) means 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.” [13]

12. Electronic Navigational Charts at Wikipedia http://en.wikipedia.org/wiki/Electronic_navigational_chart

13. ENC Definitions in PERFORMANCE STANDARDS FOR ELECTRONIC CHART DISPLAY AND INFORMATION

SYSTEMS (ECDIS) [IMO Resolutions A.817 (19), MSC.64 (67) and MSC.86 (70)] (amended March 1999)

Diagram : Example of ENC (Fugawi Marine ENC)

Diagram : Example of ENC

(Fugawi Marine ENC)


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3.3.2 SYSYEM ELECTRONIC NAVIGATIONAL CHART (SENC)

The SENC is the database that is actually accessed by the ECDIS for display generation and

other navigational functions. The database is resulting from the transformation of the ENC by the

ECDIS for appropriate use. Update to the ENC by appropriate means, and other data added by

the mariners. The SENC contains the equivalent to an up-to-date paper chart. The SENC may

also contain information from other sources.

3.3.3 RELATION BETWEEN ENC AND SENC

IMO Resolution MSC 232 provides the following definitions:

ENC: means the database, standardised as to content, structure and format, for charting and

updates issued for use with ECDIS by or on the authority of a Government, authorised

Hydrographic Office or other relevant government institution, and which conforms to an IHO

standard known as S-57/3. The ENC contains all the chart information necessary for safe

navigation. On the ship, S-57/3 data is loaded into the ECDIS in a dedicated storage area, called

the ENC database.

SENC: Since the S-57/3 format is not suitable for data processing, the ECDIS has to convert the

ENC into a different format referred to as SENC. The resulting data is then loaded into a separate

SENC database from where it is accessed by the chart display and navigational functions of

ECDIS and this database may also contain information added by the mariner or from other

sources. The ECDIS manufacturer may choose whatever format and database structure for the

SENC, provided that the ENC data is not downgraded in accuracy and/or contents during the

conversion process.

ENC ENC

Data Software Display

Updates

#1

#2

+

#1

+

#2

+

SENC

SENC1

SENC2

IHO S-57 Performed in ECDIS IHO S-52 Colours & Symbols

Diagram 1 : System Electronic

Navigational Chart


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3.3.4 CHARACTERISTIC OF ENC IN ECDIS

1. The ENC data is the only data of IHO S-57 standards transformed into the ECDIS for

display and use.

2. The standardized colour and symbol is required in accordance with IHO S-52 standards.

3. The updating of the ENC is made official through Notice To Mariner (NTM) [10]

is easy and

can be done automatically onboard ship reducing the time consuming workload manual

correction of paper charts.

4. The scale in display the ENC can be changed by the user freely by means of the display

scale.

5. Additional navigational – related information depends on the layer of display can be

manipulated by the user. These are: Base, Standard and All.

6. The ECDIS is a sophisticated navigational system that provides alarms or indications with

regard to preset safety paramaters, e.g. safe depth, safe contour etc.

7. Other navigational sources such as Global Navigational Satellite System (GNSS / GPS) [14]

,

Automatic Identification System (AIS) [15]

, radar and Automatic Radar Plotting Aid (ARPA)

[16] picture, etc. can be overlaid on the ECDIS screen for navigation purpose.

14. GNSS / GPS - Global Navigation Satellite Systems is satellite navigation systems that provide autonomous geo-

spatial positioning with global coverage.

15. Automatic Identification System (AIS) – is a short range coastal tracking system used on ships and by Vessel Traffic

Services (VTS) for identifying and locating vessels by electronically exchanging data with other nearby ships and

VTS stations

16. Automatic Radar Plotting Aid (ARPA) – is a marine radar with capability that can create tracks using radar contacts.

The system can calculate the tracked object's course, speed and closest point of approach (CPA), thereby knowing if

there is a danger of collision with the other ship or landmass.

Diagram 2 : How ECDIS works


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3.4 COMPONENTS OF ECDIS

ECDIS represents an item of equipment consisting of hardware, software and data. Whilst a high

performance PC or workstation installed in a console linked with other items of ship’s equipment, such as:

• Course to steer linked with Gyro

compass

• Rate of turn linked with a turn

indicator

• Speed and distance linked with log

• Ship position is fed from the GNSS /

GPS

• Radar data overlaid from source of

radar.

3.5 OTHER TYPE OF ELECTRONIC CHARTS AND THE DIFFERENCES WITH ENC

Not all electronic charts are in same format; many different formats exist for electronic charts.

However, two major types are now in use on merchant ships, they are vector chart and raster

charts.

Raster charts (RNC), in fact, are scanned paper charts into the pictures with adjustment made

suitable for display on the Raster Chart Display System (RCDS). This RNC is also known as

Admiralty Raster Chart System (ARCS Charts) which produced by the British Admiralty.

Vector charts are digitized charts. Countries are producing unique digital charts based on their

interpretation of IHO standards (i.e. S-57 standards)

GNSS/GPS Gyrocomp

Echo

Computer

ENC

Updates

Radar/ARPA AIS

Water level

Current Diagram 2 : Components OF ECDIS

Diagram 2 : Components OF ECDIS


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Raster Chart (RNC) Vector Chart (ENC)

Chart data is a digitized “picture” of a chart. All

data in one layer and one format.

Chart data is organised into many separate files.

It contains layer information to produce certain

symbols, lines, area, colours, and other

elements.

With raster data, it is difficult to change individual

element of the chart since they are not

separated in the data file.

With vector data, it can change individual

elements with additional data.

The differences between RNC/ARCS for RCDS/ECS and ENC for ECDIS

RNC (RCDS or ECS) ENC (ECDIS)

• Chart based system similar to paper charts.

• Will not trigger automatic alarms. Some alarm

can be generated from user-inserted information.

• Chart projection may differ between RNCs.

• Chart horizontal datum relates to the datum of

the position fixing system, may appear as a shift

in position.

• Feature cannot be simplified or removed to suit a

particular navigational circumstance. This affects

the superimposed of radar/ARPA picture.

• Cannot select different scale charts.

• May affect the readability of chart text and

symbols.

• Not possible to gain additional information.

• Not possible to display a ship’s safety contour or

safety depth.

• Different colours may be used to show similar

chart information.

• Displayed at the scale of the paper chart.

Excessive zooming in or out can seriously

degrade RCDS capability.

• In confined waters, the accuracy of chart data

may be less than that of the position fixing

system in use.

• No chart boundaries.

• Will trigger automatic alarms.


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3.6 ALARMS AND WARNING

ECDIS provide Warnings and Alarms. It combines several different functions into one computerized

system which is possible to provide alarms or display warnings (indication) when certain parameters are

met or exceeded as determine by the navigator.

Types of Warning

1. Deviating from a planned route;

2. Approach to waypoints;

3. Failure of the positioning system;

4. Vessel crossing safety contour and;

5. System malfunction or failure etc.

3.7 WHEN TO USE THE ECDIS OR RCDS

As the ENC is developed and produced by countries, it is not distributed by one stop shops like the

distribution of paper charts, hence ships using ENC and RNC is common nowadays. Therefore ECDIS

can operate in two modes:

• The ECDIS mode when ENC data is used,

• The RCDS mode when ENC data is not available.

NOTE: When RCDS mode is in use, the back-up system is the portfolio of appropriate paper charts for

the intended voyage.

3.8 ADVANTAGES OF ECDIS OVER A PAPER CHART

ECDIS is not only an adequate replacement for the paper navigational chart but also a system containing

all information important for navigation. It reduces the time-consuming manual correction of paper charts.

The ECDIS display can be superimposed with radar images and with the radar targets of ARPA; and the

vessel’s positions is continuously shown on the chart display and stored at regular intervals. Hence

manual chart exchange is no longer required.

The elements of route planning in ECDIS are waypoints and leglines to ensuring safe track keeping. The

cross distance along the leglines can be set for activation of the alarm if the vessel deviates from the

scope of leglines. ECDIS "knows" whether a vessel can pass safely through an area, on the basis of the

vessel's information fed in.


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3.9 THE RISK AND LIMITATION ECDIS

It should be noted that the ECDIS is only a tool that helps a mariner safely and effectively navigate a

ship. One of the biggest risks with the transition to ECDIS is an over reliance in the information provided.

Some limitations of the ECDIS as followings:

1. Chart Accuracy

ECDIS provides the navigator with a tactical tool which incorporates a high accuracy positioning

device. The navigator can "zoom" in on an ECDIS chart to a scale beyond the intended accuracy

of the charted information.

2. Technical limitation of other devices

The accuracy is also depends on the technical limitation of other devices linked to the ECDIS,

such as GPS, radar, etc. The mariner must be attentive to the source and accuracy of the

position fixing device utilized by the ECDIS.

3. Information Overload

The mariner is cautioned to be wary of information overload and a very cluttered display screen.

Information overload and a cluttered screen seriously degrade navigation safety for the mariner

and could result in a "technology-assisted incident".

4. Familiarization of ECDIS

A mariner must invest time and effort to mastering the device prior to his first navigational watch.

This will be crucial to the navigation safety of the vessel in the event paper charts are not required

or available on the vessel.


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3.10 ECDIS & GOOD SEAMANSHIP

Navigation with ECDIS does not differ significantly from navigation with paper sea charts. ECDIS does

not exempt mariners from conducting proper route planning. The most important points to be taken into

consideration is:

The voyage planning should consist of:

• Consultation of nautical publications;

• Checking meteorological data;

• Consultation of meteorological route advice (If applicable);

• Consideration of routing measures;

• Consideration of ship reporting systems and vessel traffic services;

• Consideration of which pilotage services are available;

• Consultation of port information;

• Collection of information on shore based rescue facilities and

• The interaction between ship's type, cargo and potential route.


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For creating a route, the mariner should consider:

• As a first step, the start and end point of a route;

• Selection of convenient course alteration points;

• The required width of the track;

• The cross track error (XTE) that can be permitted at different stages;

• The maximum allowed difference off track from the planned route;

• The assignment of route parts to great circle or rhumb line track;

• The maximum allowed distance off track and

• The radius of turn and for course alterations.

The following further points should be considered:

• Safety speed;

• Speed reductions to enable difficult passages by day, to catch tide windows and to make use of

tidal streams;

• Underkeel clearance;

• Engine maintenance on high sea (we are thinking of cleaning the funnel exhaust uptakes);

• Turning circle and manoeuvre details;

• Routine position fixing with the use of all available position fixing systems;

• Environmental protection and

• Security precautions against incidents (human life, ship, cargo).

Once at sea, mariners should consider at least following points:

• Routine checks of the navigational equipment;

• ETA at each course alteration point and at each other point significant for the entire voyage;

• Meteorological conditions and the traffic situation.

• Fuel usage and bunkering;

• Fresh and drinking water planning if needed;

• Harbours of refuge;

• Alternate ports for contingency;

• Sunrise, Sunset, nautical Twilight;

• Expected time of landfalls;

• Action on failure to make a landfall;

• Clock time checks;

• Zone times ashore and

• When to change ships time.


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4.0 CONCLUSION

The rapid development of technology from the last decades has also contributed in the hydrographic and

maritime environment. From the technology using paper now it goes into gadgets and paperless

technology. In line with the establishment of IHO and IMO which were to support the safety of navigation

and protection of the marine environment then it produced the Electronic Chart Display and Information

System.

ECDIS is never been replaced the old paper charts but it is more like in advance of assisting into a better

and safer navigation. Thus it still maintained the basic features such like depth and pilotage information

with more additional attributes which the paper is limited.

ECDIS consists of components which integrate with navigation information from Radar, ARPA Image

instead of the ENC. It also get additional information from AIS, Autopilot, Echo Sounder and other

instrument that helps in voyage and routing. Beside it also integrate with GPS for positioning of the vessel

which is can be shown in ENC.

And today we can find many navigation and mapping companies have produced this so-called ENC and

ECDIS software. For an example, Fugawi based in Canada (www.fugawi.com) which produced and

supplied desktop, mobile even a web – based navigation and mapping softwares. They have produced a

software; Fugawi Marine ENC which can applies navigation into a smaller device such as iPAD and

iPhone. Besides it can produce 3D model of navigation chart with AIS support, weather overlay, planning

and transfer routes, waypoint between handheld and PC. This development is very helpful in advance of

better navigation in the future.

It also a recommendation in the future that the mandatory to use this ECDIS in every vessel. Since lately

there were a lot of incidents of collisions between vessel happened all around the world. And these

collision not only bad for the logistic and vessel but also towards the marine environment such as oil spills

and other chemicals pollution.


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5.0 REFERENCES

1. PERFORMANCE STANDARDS FOR ELECTRONIC CHART DISPLAY AND INFORMATION

SYSTEMS (ECDIS) [IMO Resolutions A.817 (19), MSC.64 (67) and MSC.86 (70)] (amended

March 1999)

2. ANNEX 24, RESOLUTION MSC.232(82) (adopted on 5 December 2006) ADOPTION OF THE

REVISED PERFORMANCE STANDARDS FOR ELECTRONIC CHART DISPLAY AND

INFORMATION SYSTEMS (ECDIS)

3. Facts about electronic charts and carriage requirements Prepared by Primar Stavanger & IC-ENC

Joint Information Working Group (JIWG)

4. Differences Between Maps & Charts, The United States of Office of Coast Survey NOAA

http://www.nauticalcharts.noaa.gov/mcd/learn_diff_map_chart.html

5. ECDIS (Electronic Chart Display and Information System): Part1: How ECDIS works, The Pilot

Online Edition http://www.pilotmag.co.uk/2010/03/09/ecdis-electronic-chart-display-and-

information-system-part1-how-ecdis-works

6. FUGAWI Marine ENC GPS Navigation Software

http://www.fugawi.com/web/products/fugawi_marine_enc-in.htm

7. ENCs, ECDIS and Bathymetry IHO http://www.iho-ohi.net/english/encs-ecdis-and-bathymetry/

8. Legal, IMO http://www.imo.org/Legal/mainframe.asp?topic_id=60

9. Fundamentals of Mapping http://www.icsm.gov.au/mapping/maps_charts.html#jargon

10. ECDIS Basic http://www.fuerstenberg-dhg.de/index.php?id=ecdis_startseite&L=1

sug514 - hydrographic surveying - topo map vs navigation chart, enc & ecdis

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