Fundamental of Hydrographic Surveying by PolisasLib2

THE FUNDAMENTAL OF HYDROGRAPHIC SURVEYING

Sr. Noor Khairul Idham Bin Nordin 0 Politeknik Sultan Haji Ahmad Shah

Declaration

The Fundamental of Hydrographic Surveying Author Sr. Noor Khairul Idham Bin Nordin, MRISM Department of Civil Engineering

Publisher POLITEKNIK SULTAN HAJI AHMAD SHAH SEMAMBU, 25350 KUANTAN, PAHANG DARUL MAKMUR

All right reserved. No part of this publication may be reproduced or distributed in any form or by any means, or stored in a database or retrieval system, without prior written permission of the solely private publisher as stated above

Acknowledgement

In the Name of Allah, Most Benevolent, Ever Merciful All Praise to be, to Allah S.W.T…. Assalamualaikum w.b.t

While

preparing

this

e-book

“The

fundamental

Hydrographic Survey”, I was in contact with many individuals, academicians and practitioners. The entire individuals have contributed to help me understand and practice the knowledge towards successful finished e-book in the geomatics field. I would like to express my sincere appreciation to my Head of Department, Madam Rosmiza Binti Wira for his encouragement, assistance, patience, criticism and guidance on me continuously. Appreciation also gives to Mr Saiful Hazman, Ts Shafarim and Sr Asrul Bin Zakaria that had initiated the idea, sharing knowledge and in helping me in the e-book of the project. My sincere appreciation should also be extended to Madam Sr Noraishah binti Mustapa, Head of Geomatik Programme, Mr Ameer Shafuan bin Mohd Kifli Precise Subsurface and Mr Faiz bin Hj Alias Jurukur Mahabob and Co for idea and knowledge sharing on the fundamental of hydrographic survey. I am extremely thankful to my wife Norhayati bin Mohamad Yunus, my sons Muhammad Ammar Zakwan and Aqil Ilman, my parents and my siblings for encouragement and support of my first e-book project. Finally, I must express my dearest friend, Mr Asnawi, Mr Fuad, Mr Nizar, Mrs Sharifah, Mr Faez (proofread), and who are involved either directly or indirectly for their understanding, support, encouragement, and motivation in my journey for ebook project. This accomplishment would not have been possible without them. Thank you.

Abstract

Hydrographic Surveying is a course offered to Malaysian Polytechnic Diploma in Geomatics students. This course is offered to students in semester 5. In this course, various topics are discussed such as Introduction to Hydrography, Tides, Planning in Hydrographic Survey, Positioning, Sounding and Chart production. This E-Book is produced to facilitate students, especially Malaysian Polytechnic Geomatics diploma students for their reference. In Malaysia, the lack of reference sources, especially e-books in the field of hydrography are one of the reasons students lack reference sources in completing assignments and exercises. In today's digital era, the production of e-books is very clear and accurate in being a source of reference for students, especially the Diploma in Geomatics of Malaysian Polytechnic. This E-Book "The Fundamentals of Hydrography Survey" explains more on topics related to hydrographic survey. In this e-book also explains about the process of carrying out Hydrographic Survey work for the purpose of producing survey plans that are equivalent to international standards, namely the International Hydrographic Organization (IHO). Therefore, with the production of this ebook, it is hoped to increase knowledge and become a reference for students related to hydrographic surveying.

Table of Contents Bil 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29

Content Declaration Acknowledgement Abstract Definition of Hydrography Importance of Hydrography The purpose of Hydrography Scope of Hydrography Survey Hydrography governing bodies The role of Hydrography Surveyor Nautical Chart Notice to Mariner Tides Spring Tide and Neap Tide Tidal Level Hydrography Survey Planning Safety Procedure Positioning Positioning Method Differential Global Positioning System (DGPS) Principle of DGPS Sounding The Echo Sounder Frequency of Echosounder Echosounder source of errors Bar Check Calibration Side Scan Sonar Sub Bottom Profiling Chart Production Reference

Page 1 2 3 5 6 7 8 9 - 10 11 12 13 14 15 - 16 17 - 18 19 20 21 22 23 - 24 25 26 27 28 29 - 30 31 32 – 33 34 35 – 36 37

SURVEYING

HYDROGRAPHY

IHO Definition of Hydrography

That branch of applied sciences which deals with the measurement and description of the features of the seas and coastal areas for the primary purpose of navigation and all other marine purpose and activities, including- inter alia – offshore activities, research, protection of the environment, and prediction services. (IHO Pub. S-32)

Importance of Hydrography In addition to supporting safe and efficient navigation of ships, hydrography underpins almost every other activity associated with the sea, including:

• Coastal Zone Management • Resources exploitation – fishing, minerals, etc. • Environmental protection and management • Maritime boundary delimitation • National marine spatial data infrastructures • Recreational boat • Maritime defence and security • Safe and efficient operation of maritime traffic control • Tsunami flood and inundation modelling • Tourism • Marine science • Exploration and exploitation of marine resources

The Purpose of Hydrographic Survey

The purpose of Hydrographic Surveying can be considered as to collect, with systematic survey at sea, along the coast and inland, georeferenced data related to: Depths in the area of interest (including all potential hazards to navigation and other marine activities).

Shoreline configuration, including man made infrastructure for maritime navigation i.e. all those features on shore that are of interest to mariners.

Sea bottom composition

Tides and currents

Physical properties of the water column

Scope of Hydrography Surveying

Coastal Hydrography - Coastal hydrographic involved port and harbour development, coastal erosion monitoring and the most important thing is to ensure navigational safety - Port and harbour maintenance (dredging), coastal engineering (beach erosion and replenishment studies), coastal zone management.

Off-Shore Hydrography - Concern to most surveys is the nature of the sea floor materials (i.e. sand, mud, rock) due to its implications for anchoring, dredging, structure construction, pipeline and cable routing and fisheries habitat.

Oceanic Hydrography - Collecting data at the sea area to give the picture of sea-floor geomorphology. - Note: Geomorphology = the scientific study of the nature and history of the landforms on the surface of the Earth and other planets, and of the processes that create them

Hydrographic Governing Bodies

INTERNATIONAL HYDROGRAPHIC ORGANIZATION (IHO) •

• • •

The International Hydrographic Organization is an intergovernmental consultative and technical organization that was established in 1921 to support safety of navigation and the protection of the marine environment. Location Monaco. Produce and publish the international (INT) Chart for small, medium and larger scales. Give education and training in creating and maintaining a modern hydrographic service.

JABATAN UKUR DAN PEMETAAN MALAYSIA (JUPEM)

•

• •

JUPEM is one of the earliest agencies in Malaysia that performs the survey and mapping activities which started in 1885 when the Department of Survey Johor was established. Develop the database for national geodetic marine infrastructure system which consists of the data of geodetic coordinate, attribute, topographic of seabed, marine geoid and hydrography. Determine the maritime boundary between the states in Peninsular Malaysia by the laws of Malaysia and the Law of the Sea Convention, 1982. Provide technical expertise to finalize the international maritime boundary with neighboring countries in accordance with the Law of the Sea Convention (Konvensyen Undang-Undang Laut), 1982.

ROYAL MALAYSIAN NAVY (TLDM)

•

• • •

The responsibility to do hydrographic measurement in Malaysia’s national waters were handed over to the Hydrographic Branches of Royal Malaysian Navy (RMN)Pusat Hidrografi Nasional (PHN). In 1969, a mine-sweeper ship Larichi Class type was given to TLDM to be used as hydrographic vessel. The ship was named as KD Perantau and become the first surveying ship in TLDM history. In 1977, the TLDM acquired another ship named KD Mutiara. On 15 April 2003, a new building Pusat Hidrografi Nasional (PHN) was constructed in Pulau Indah, Klang. PHN Products – Publish Notice to Mariners, Electronic Notice to Mariners, Chart Index, Nautical Chart, Electronic Navigation Chart, Tide Table, Give information about maritime zone in Malaysia.

PORT AUTHORITY •

•

The Port Authority shall consist of a Chairman who shall be appointed by the Yang di-Pertuan Agong and the General Manager for the time being of the port. Currently, Malaysia has a total of seven (7) major Federal ports namely Port Klang, Johor Port, Port of Tanjung Pelepas, Kuantan Port, Penang Port, Bintulu Port and Kemaman Port. Meanwhile, the ports in Sabah and Sarawak are under the jurisdiction of the State Government of Sabah and Sarawak respectively. Function of Port Authority

• • • •

To operate and otherwise maintain the port in respect of which it is established. To undertake all or any work of every description of or in connection with the loading, unloading and storing of goods or cargo in the port To construct, maintain, repair and use wharves, docks, piers and bridges within the limits of the lands vested in it To clean, deepen or improve any portion of the port, and for any of such purposes, to construct, maintain, and operate dredgers or other appliances

The role of Hydrographic Surveyor •

Hydrographic surveying is important in a variety of marine activities such as mineral resource management including oil and gas, fishery management, submarine cable routes, marine archeology, search and recovery efforts, and safe navigation.

• Hydrographic survey technicians work long hours, sometimes in stressful situations.

• They must learn to use a variety of tools and equipment, ranging from sonar systems to computers and peripherals, GPS, sampling equipment, and deck equipment. • These courses include oceanography, physics, computer skills, navigation, marine mechanics, geophysical surveying (including echo sounders, sub-bottom profiling, etc.), and underwater acoustics. • They must conduct pre-cruise logistics and survey planning, conducting field operations, managing data, and maintaining equipment.

• Conducting field operations involves everything from troubleshooting field equipment to deploying equipment to maintaining field logs. In another example, managing data involves formatting and organizing data as well as contributing to cruise reports.

Nautical Chart • A Nautical chart is a graphic representation of a maritime area and adjacent coastal regions. Depending on the scale of the chart, it may show depths of water and heights of land (topographic map), natural features of the seabed, details of the coastline, navigational hazards, locations of natural and man-made aids to navigation, information on tides and currents, local details of the Earth's magnetic field, and man-made structures such as harbors, buildings, and bridges.

The Purpose of Nautical Chart

Positioning Navigation Facilities to mariners Intermediary information for all maritime traffic Explain and show information depth and shape seabed Indicates a pilot object sailing direction like home fire, control tower, buoy and useful details to sailor

TYPES OF NAUTICAL CHART Port Chart Coastal Chart Offshore Chart

Notice To Mariners

Danger to navigation" are inadequately charted natural and cultural features

• •

Submerged features with depths less than 11 fathoms (66 feet) in navigable waters Items found to be significantly shoaler than charted

•

Incorrect or uncharted clearances of bridges or overhead cables Off-position or incorrectly labeled floating or fixed aids

Port Marine Safety Code

The Port Marine Safety Code states that the harbour authority has a duty to conserve the harbour so that it is fit for use.

The Port Marine Safety Code also stipulates that the Broads Authority, as an appointed harbour authority, has the following duties: •

To find, mark and monitor the best navigable channel or channels in the harbour.

•

To have effective arrangements for the publication of appropriate hydrographic information.

TIDES

Tides are

the rise and

fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon and the Sun, and the rotation of the Earth.

TYPES OF TIDE

Semi-Diurnal Tides • Two high and two low tides daily, with small differences in the high and low water height • Level of height of two high tides and two low tides a row is about the same • Atlantic coasts of North America and Europe

Diurnal Tides

• One high and one low tide daily. • It only occurs in some places in Mexico, North Sea, Vietnam, China, etc

Mixed Tides • Usually, two high and two low with a large inequality between high water

SPRING TIDES AND NEAP TIDES

SPRING TIDES • Rise very high and fall very low • New Moon days and full moon days • Sun, Moon and earth are in straight line

•

Spring tides occur when the moon and sun are pulling together. This

•

happens during new moons and full moons. Springs tides have the highest high tides and the lowest low tides during any given tidal cycle.

NEAP TIDES • Neither rise very high nor fall very low • Quarter moon days

• Sun, Moon and earth are in right angle

• Neap tides occur when the moon and the sun pulling at right angles to each other. This happens during a ¼ and ¾ moon. These tides are more moderate.

TIDAL LEVEL Permanent Mark or Benchmark (BM) Highest Astronomical Tide (HAT) Mean High Water Springs (MHWS) Mean High Water Neap (MHWN) Mean Sea Level (MSL) Mean Low Water Neap (MLWN) Mean Low Water Springs (MLWS) Lowest Astronomical Tide (HAT)

MEAN SEA LEVEL (MSL) • Mean Sea Level (MSL) is average of hourly readings taken over one tidal cycle at least, or better a lunation (29.5 days) or 6 months or 18.6 years (one cycle of moons nodes). • MSL is considered a level plane over a long stretch of coast. Except for bottom mounted installations, any tide gauge deployment must be accompanied by the erection of a nearby tide pole which can be used for levelling to benchmarks, calculation of MSL, and for connecting a gauge zero to Sounding Datum (SD). • MSL is the best vertical reference level we have, and as such is the BASIC REFERENCE LEVEL for tides.

MEAN HIGH AND LOW WATER SPRINGS (MHWS & MLWS) •

These are the mean height of two successive HWs and LWs respectively, throughout a year when the average maximum declination of the Moon is 23.5º, during those periods of 24 hours (approximately once every 14.5 days) when the range of the tide is greatest. •

These levels also vary with changes in Mean Sea Level, and from year to year in a cycle of 18.6 years.

•

Mean High Water Springs (MHWS) is the average value of the height of high water at spring tides. All height on a chart refers to MHWS as the height datum. This means that clearances under bridges and the distance to a horizon are the minimum values to be expected by the navigator. •

Mean Low Water Springs (MLWS) Is the average value of the height of low water at spring tides.

MEAN HIGH AND LOW WATER NEAPS (MHWN & MLWN) •

•

These are the mean heights of two successive HWs and LWs respectively, throughout a year when the average maximum declination of the Moon is 23.5º, during those periods of 24 hours (approximately once every 14.5 days) when the range of tide is least.

These levels will also vary with changes in Mean Sea Level, and from year to year in a cycle of 18.6 years.

•

Mean High Water Neaps (MHWN) is the value of the heights of high water at neap tides.

•

Mean Low Water Neaps (MLWN) is the value of low water at neap tides.

LOWEST ASTRONOMICAL TIDE (LAT) •

•

By definition, LAT is the lowest level that can be predicted to occur under average meteorological conditions and under any combination of astronomical conditions.

There is no simple formula or rule available to calculate LAT from observations or tidal constituents. It can only be obtained properly by studying tidal predictions covering several years (18.6 years ideally), as the level of LAT will not be reached every year.

CHART DATUM

• On a chart the reference datum for depths is called chart datum • It is usually the same or very close to the surveyor sounding datum • On a chart the reference datum for depths is called chart datum • Chart Datum is defined by the International Hydrographic Organization (IHO) as a level below which the tide will but seldom fails. In non-tidal waters, CD is normally established at MSL.

HYDROGRAPHY SURVEY PLANNING

A survey begins long before actual data collection starts. Some elements, which must be decided, are:

Survey planning is a complex process requiring considerable attention to detail, a flexible approach, good management and effective decision-making. If the planning is through, the changes are that the survey will be good too (C13 Chapter 7 IHO)

SAFETY PROCEDURE The International Convention for the Safety of Life at Sea (SOLAS) is an international maritime treaty which requires Signatory flag states to ensure that ships flagged by them comply with minimum safety standards in construction, equipment and operation.

Personal Life-Saving Appliances • Lifebuoys, Life Jackets, Immersion suits and thermal protection aids

Visual Signal • Lifeboat and life raft

Rescue Boats

Line Throwing Appliances

Launching and Embarkation Appliances • Life raft launching procedure

Survival Craft • One or more totally enclosed lifeboat on each side of ship to accommodate all person on board

POSITIONING

•

A major element of the hydrographic survey is the dynamic positional control of the survey vessel and until the method to be used has been chosen, the sounding speed, time schedules, costs etc., cannot be assessed.

• These may be lines of bearing, arcs of range, angles constituting an intersection or resection fix, or combinations of any of these.

The importance of Positioning •

Every hydrographic job requires positioning information for specific point

•

Example: to determine the position of a point that the depth was recorded from echo sounder

•

The inaccuracy of positioning would place the point to be incorrect

POSITIONING IN HYDROGRAPHIC SURVEY

Some examples of hydrographic survey:

a) Engineering Survey at Lake, River and Coast Line harbour construction, marina, jetty and bridges, dredging project b) Hydrographic Survey in Port Area wharf survey / port, pre&post dredging survey c) Engineering Offshore Survey exploration project (oil and gas), platform positioning, pipe and cable positioning, clean boundary survey

POSITIONING METHODS

Optical Method

Electromagnetic Position Fixing System (EPF)

Differential Global Positioning System (DGPS)

Acoustic Method

• Intersection Method (Two Total Station)

Optical Method

• Distance and Bearing Method (Total Station)

• Kaedah silang alikan (Sekstan) • Two Distance Method (EDM)

Differential Global Positioning System (DGPS)

•

A positioning technique that uses two receivers, one (the differential station) at an unknown location, and the other (the reference station) at a known, fixed location.

•

The reference receiver computes corrections based on the differences between its actual and observed ranges to the

satellite being tracked. •

The coordinates of the unknown station can be computed with great precision by applying these corrections to the satellite data received at the differential station.

BEIDOU (China)

GPS (United States)

GAGAN (India)

GLONASS (Russia)

QZSS (Japan) GALILEO (European)

NIGCOMSAT-1 (Nigeria)

Global Navigation Satellite System (GNSS)

•

GNSS is a satellite system that is used to pinpoint the geographic location of a user's receiver anywhere on land and sea, in the air or in Earth orbit.

Differential Global Positioning System (DGPS)

Advantage of the code phase (DGPS) over the carrier phase (RTK) •

Wavelengths are much longer than the carrier wavelengths, eliminating the ambiguity problem.

Disadvantage of the code phase (DGPS) over the carrier phase (RTK)

•

Longer wavelengths decrease the system accuracy

•

Longer wavelengths are more affected by signal multipath.

Principle of DGPS

•

• • •

• • • •

•

In navigation applications – these error corrections are needed in real-time – communication (radio) link is needed! Radio format such as RTCM, NMEA In practice, some delay will occur in the rovers for the corrections – latency The closer the rovers to the reference station and the shorter the latency time – the more accurate the correction The reference ground station (s) at known locations receive GPS signals

Knowing position of the station, the pseudorange to each SV is calculated based on the almanac. The measured pseudorange PRM (t) is determined The pseudorange correction is calculated as the difference. The pseudorange correction PRC(t), and the Range Rate Correction RRC(t) are sent from the reference ground station.

DGPS is a technique which allows the removal of correlated systematic errors that are computed by the comparison of known and measured ranges at a reference location. These may then be applied in the form of corrections to other receivers in the area. The basic premise of conventional DGPS is therefore based on a common error assumption i.e. that the errors quantified at the reference station are identical to those experienced by the mobile user.

SOUNDING

•

Depth determination is a fundamental task for a hydrographer, which requires specific knowledge of the medium, of underwater acoustics, of devices available for depth measurement, of complementary sensors for attitude and heave measurement and proper procedures to achieve and meet the internationally recommended standards for accuracy and coverage as articulated in IHO publication S-44 5th Edition.

DEPTH MEASUREMENT CAN BE DIVIDED INTO TWO

• Indirect Method

The echo sounder belongs to the category of indirect methods. With the echo sounder, the time required for the sound to travel from the ship to the seabed and back to the ship is registered and indicated as depth

• Direct Method

Manual depth measurement techniques are used for many under water engineering and construction applications

Lead Line Method Echo Sounder Sounding Pole Method

Level Rods Method

The Echo Sounder •

Echo sounder (also refer to echo sounding or acoustic depth measurement systems) is a type of SONAR (Sound NAvigation and Ranging) used to determine the depth of water by transmitting sound pulses into water.

•

The time interval between emission and return of a pulse is recorded, which is used to determine the depth of water along with the speed of sound in water at the time.

• Frequency The characteristics of an echo sounder are determined by the acoustic parameters namely:

• Band Width • Pulse Length

Recorder Trans. mark Echo Trace Controls

Transmitter Receiver

T/R switch

Water level Transmit pulse

Transducer

Echo return

The basic of echo sounder

The frequencies of bathymetric echo sounders are typically:

•

Waters shallower than 100 meters: frequencies higher than 200 kHz; • Waters shallower than 1500 meters: frequencies from 50 to 200 kHz; • Waters deeper than 1500 meters: frequencies from 12 to 50 kHz; The frequencies for sediment echo sounders are below 8 kHz

Basic component of Echo Sounder

Frequency In

Frequency Out

Echo Sounder source of errors Echo Sounder requires: • Correction for transducer draught • Correction for speed of sound velocity (STP data input) • Correction for tidal height

Echo Sounder resolution depends on •

Pulse duration or length

•

Incident angle to the target

•

Sensitivity of target

•

Transmission beamwidth

• Single Beam Echo Sounder (SBES)

• Multi Beam Echo Sounder (MBES)

• Single Beam Echo Sounder (SBES)

• Single beam echo sounder contains one transmitter and receiver, and it covers a particular area • SBES may have a narrow beam when high directivity is required or a wide beam when directivity is not the main concern but the detection of minimum depths or obstacles on the seafloor is the priority

• Multi Beam Echo Sounder (MBES)

• Multibeam echo sounder systems are used to increase bottom coverage of the water covered area • It is the most advanced acoustics tool for remote observations and characterization of the seafloor • Multibeam echo sounders consisted of an extension of single beam echo sounders

Bar Check Calibration The three parameters the echo sounder needs to determine the depth accurately are:

•

Draft

•

Sound Velocity

•

Index

• Draft is the distance from the water surface to the face of the transducer • Sound Velocity is the average speed of sound in the water column • Index errors are any delays caused by the transducer elements and analogue filters in receiver of the echo sounder • Draft and index errors are best determined when the bar is placed close to the face of the transducer, and sound velocity is best determined when the bar is at its deepest

Procedure to perform the Bar Check Calibration

ii. iii. iv. v.

vi. vii. viii. ix.

Due to the high potential for local temperature or salinity variations in typical river and harbor projects, the resultant effect on the velocity of sound must be measured directly at the work site. Setup the equipment and start the echo sounder control program. Set the initial speed of sound. Usually set to 1500 m/s. Set the measure draft (how deep the transducer is as measured from the water surface to the transducer face). Lower the bar into the water column below the transducer and place it at 5 feet below the water’s surface. The Digitizer in the echo sounder CV will expect to see a target at that 5.00-foot depth while rejecting all other returns (including those from the bottom). Adjust the index to the correct depth. Change the bar depth in the echo sounder control program. Adjust the sound velocity up or down until the digitized depth matches the measured bar depth. Repeat steps iii, iv, v and vi to verify the calibration procedure until your reading matches the depth of the bar.

Side Scan Sonar Side Scan Sonar Application

• Shipwreck location and salvage • Archaeological mapping • Pre and post-dredging sediment distribution mapping • Identification of seabed type for sub-sea diamond mining • Pipeline and cable route surveys • Site survey for drilling rigs, road construction, bridge etc • Mapping seamounts, ocean ridges and other major tectonic features • Mine hunting • Identifying seabed plant colonisation

SIDE SCAN SONAR [Side scan sonar was developed in the 1960s for use as a wreck location tool. Since then its use has become standard throughout the marine surveying industry, from mapping of large tectonic seabed features to archaeological inter-tidal surveys This image is a record of the instantaneous intensity of the backscatter and is affected by the following factors: a) Sonar frequency b) The geometric relationship between the transducer and the target object c) Physical characteristics of the surface d) Nature of the surface (composition, density.]

Sub Bottom Profiling Survey •

Underwater acoustics have for many years been a fundamental tool for oceanography and marine geology because of the ability of these methods to determine physical properties of the seafloor, and to identify geological acoustic reflectors below the seafloor

•

A sub-bottom profiling system was used to obtain information of the sediments beneath the surface of the water bottom. In other words, acoustic sub-bottom profiling systems have been designed to acquire information about geological boundaries well below the seafloor.

Principle of Sub-Bottom Profiling •

Sub-bottom profiling systems comprise a sound source, either towed behind a vessel or firmly mounted to the hull that produces an acoustic pulse of set frequency, power, and time duration.

•

The acoustic pulses generated will travels through the water column and penetrates the seafloor.

•

Some of the acoustic signal is reflected from the seafloor, whereas the remainder penetrates the seafloor and is reflected when it encounters boundaries between layers that have different acoustic impedance.

CHART PRODUCTION

Main purpose of Bathymetric Chart

•

Bathymetric charts are designed to present accurate, measurable description and visual presentation of the submerged terrain.

Main things obtained after the sounding operation was performed

•

Echogram

•

Sounding Book

•

Track Plot

•

Tide Record

Information in Final Chart

(i) Title (ii) Line of Boundary Project (iii) Grid Line (iv) Scale and scale bar (v) Horizontal control stations (vi) BenchMark (BM) (vii) Datum Existing

The process to get the charted depth

• Process the position data • Process the depth data • Interpolate the tide data

• Plotting datum line at echogram • Measure the chart depth to get the charted depth

Reference Noor Khairul Idham Nordin, Syamsul Anuar Abu Kasim. (2016). Fundamental of Hydrographic Survey. Politeknik Sultan Haji Ahmad Shah.

Razali Mahmud (2015). Nota Ukur Hidrografi. Universiti Teknologi Malaysia.

Anne Lafrance (1994). A Guide to planning a Hydrographic Survey. Ontario Land Survey

Monograf Hidrografi Asas (2010), Universiti Teknologi Malaysia

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