psm1 - geoid based seamless vertical datum for marine cadastre application

UTMUNIVERSITI TEKNOLOGI MALAYSIA

GEOID BASED SEAMLESS GEOID BASED SEAMLESS VERTICAL HEIGHT DATUM FOR VERTICAL HEIGHT DATUM FOR

MARINE AREAS MARINE AREAS TECHNICAL WRITINGTECHNICAL WRITING

(SGU4922) (SGU4922)

GROUP: 4GROUP: 4Presented by:Presented by: Mohd Amsyar Bin Abdullah Mohd Amsyar Bin AbdullahSupervised By: Dr. Abdullah Hisham OmarSupervised By: Dr. Abdullah Hisham Omar

CONTENTSCONTENTS

1.0 INTRODUCTION

1.1 Problem Statement1.2 Objectives Of Study1.3 Scope Of Study1.4 Significance Of Study

2.0 LITERATURE REVIEW3.0 RESEARCH METHODOLOGY4.0 PRELIMINARY RESULTS5.0 CONCLUSIONS6.0 REFERENCES7.0 GANT CHART

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1.01.0INTRODUCTIONINTRODUCTION

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The GPS technique provide position in three dimensional coordinates in terms of Cartesian coordinates X, Y and Z or geodetic latitude (lat), longitude (long) and ellipsoidal height (h) offers an alternative to conventional leveling technique in height determination.

Traditionally, orthometric height which refers to the geoid are normally used in everyday application rather then the GPS derived ellipsoidal height.

Nowadays, Malaysia has been implemented this GPS leveling techniques by established our own geoid model which known as myGEOID to convert the GPS ellipsoidal height into orthometric height.

This technique has been done in surveying works inland that need the accuracy of centimeter level such as topographic maps, engineering design and construction project plans. (Khairul, 1995).

1.01.0INTRODUCTIONINTRODUCTIONBathymetry surveys may be conducted for many different reasons, including the planning of hydropower plants, the locating of mineral resources, especially oil or gas, planning navigational routes, or marine exploration.

As aforementioned in the introduction part, the bathymetry is determined by depth which based on Chart Datum as its vertical datum and to determine the chart datum, we have to do the tide gauge observations.

The advance of GPS positioning nowadays have provide us to do the GPS heighting which only used the geoid as its vertical height datum.

Furthermore, MyGeoid has been established in peninsular Malaysia and also in Sabah and Sarawak. So, by using this geoid model, we can use the advantages of high-accuracy GPS positioning to determine the height of terrain (seabed topography) relative to geoid (msl).

This study will take advantage of this myGEOID to develop a seamless vertical height datum for marine areas as well as for inland.

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1.11.1Problem StatementProblem Statement

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Traditionally, bathymetric data has been collected relative to a sounding datum, then translated to chart datum for storage and chart production. As a result, most legacy bathymetric data contains depths relative to some local chart datum.

The following is a listing of some chart datum definitions:•MLW - Mean Low Water•MLLWLT - Mean Lower Low Water Large Tide•MLLW - Mean Lower Low Water•LNT - Lowest Normal Tide•LLWLT - Lower Low Water Large Tide•LAT - Lowest Astronomic Tide (atmospheric and oceanographic effects removed)

In offshore works, the most significant challenges in traditional hydrography is establishing the relationship between the instantaneous water surface and chart datum, away from tide gauge locations as the chart datums are only fully valid at the location of the tidal station (where the tides are observed).

1.11.1Problem StatementProblem Statement

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Even if MSL is the same at two locations (relative to the geoid), the low water datum will likely be different.

In the past, vertical land (topography) and ocean (bathymetry) data were collected for different purposes, using different methods and related to different vertical reference surfaces.

The need to merge the two data types has driven the need to resolve these differences. So, in the future there will be only a vertical height datum that is used in topography (land) and bathymetry (ocean) which is the geoid.

1.21.2Objectives Of StudyObjectives Of Study

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1) To study Land Survey Datum (LSD) and Chart Datum.

2) To generate seabed topography based on seamless vertical height datum using geoid model (myGEOID).

3) To analyse the suitability of geoid based seamless vertical height datum.

1.31.3Scope Of StudyScope Of Study

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The study area chosen is the coastal area which is at Nusajaya, Johor.

To understand the GPS derived heights that must be transformed from the ellipsoid to the geoid (msl).

Using ArcGIS software to generate the seamless land based vertical height datum to marine based vertical height datum.

Compare the results of generated seabed topography. (based on MSL and CD as the vertical datum)

Develop a seabed topography database that is based on the geoid vertical height datum.

1.41.4Significance Of StudySignificance Of Study

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For coastal zone management surveys, it is important to define bathymetry relative to existing land mapping data, for example, the depth of the near-shore bathymetry relative to a beach profile for erosion monitoring or for sand renourishment.

Other coastal zone management issues that need of the seamless vertical height datum is as following:•floodplain mapping•storm surge and tsunami modeling•sea level rise scenarios•shoreline mapping and change analysis•planning and development of coastal zone

The coastal zone encompasses a wide swath along the shoreline that includes both the land and sea, and properly merging information from the two is essential for the analysis of coastal processes and land use of land topography.

2.02.0LITERATURE REVIEWLITERATURE REVIEW

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GPS PositioningAccording to Seker, Z., (2002), point positioning on the earth means that

determining the three dimensional coordinates of the so-called point with respect to a reference system.

Point coordinates given by GPS is in Ellipsoidal Geodetic (ϕ , λ , h - latitude, longitude and height) or Geocentric Cartesian Coordinate Systems (X , Y , Z).

Vertical Height Datumzero surfaces to which elevations or heights are referred.

1. Geodetic surface - geoid2. Mathematical surface - ellipsoid3. Tidal surface – msl

- chart datum


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Ellipsoid Surface

mathematical model of the Earth which includes a set of numbers for the size and shape of the Earth because the Earth is slightly flattened at the poles.(Shahrum, S., Majid, A., 1994)

A flattened sphere, which is known as an ellipsoid is used to represent the geometric model of the Earth (National Geospatial-Intelligence Agency, 2010)

Geoid Surface

zero surfaces as defined by the Earth's gravity which is approximated by MSL. (National Geospatial-Intelligence Agency, 2010).

According to Fotopoulos (2003), the classical Gauss-Listingdefinition of the geoid is given as an equipotential surfaceof the Earth's gravity field that coincides with the mean sea level.


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Mean Sea Level (MSL)

According to M. Razali (2008), MSL is the average level reached by the sea water for a period of time and this level nearly overlap with geoid and the best period of the tidal observations made is 18.6 years which is a cycle of moon node.

MSL is not coincide with geoid because the sea level measurements from tide gauge are ambiguous which means the records do not only reflect sea level change but are also contaminated by vertical land movements, variation in winds, ocean currents, river run-off, salinity, water density and fluid withdrawal such as ocean loading, water, oil and gas. (Azhari, M., et., al, 2001).


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Chart Datum (CD)

Used as zero surface in the determination of water depths and tides and it is used on nautical charts to reference water depths and for navigational use.

Lowest Astronomical Tide (LAT) is chose as the CD as it is the lowest level of sea

water which is the sea water will never lower than this LAT value. LAT is determined by predicted the tide for a period of 18.6 years. (Mohd Razali et.al, 2008).


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myGEOID

According to Seker, Z., et. al., (2002), modeling the difference between gravimetric and GPS/levelling geoids will improve the geoid height determination accuracy at a point observed and, thus, help determination of orthometric heights from GPS observations.

contains the height of the geoid (or the value of N) relative to the GRS80 reference ellipsoid surface

GPS users in Malaysia can obtain their values of the orthometric height on the accuracy of 5 centimeters across the country. (Pekeliling KPUP Bil. 10, 2005).


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The final geoid model was computed by fitting the GPS-levelling and the gravimetric geoid to produce Malaysia’s first ever geoid model – MyGEOID as the absolute comparison of gravimetric geoid-ellipsoid separation with the geometric (GPS minus benchmark heights) equivalent revealed existence of datum bias, or datum ambiguity.

final gravimetric geoid for Peninsular Malaysia

(WMGEOID04)

final gravimetric geoid for East Malaysia (EMGEOID05)


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GPS Heighting - GPS measures heights related to the ellipsoid (h)

- myGEOID provides geoid height value (N)

(1) GPS Levelling Over Land

H orthometric = h GPS – N geoid heigt

• P


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(2) GPS Levelling Over Water Body

Description of symbols used in Figures are as follows:H = orthometric height (height from geoid to terrain)h = ellipsoid height (determined from coordinates of receiver)N = geoid height (determined from geoid model)D = depth measured by echo sounder from transducer to terrainK = offset from antenna of receiver to transducer

H = h – N – (K+D)positive H indicates height of

terrain above sea level

GPS Heighting at Lake/River


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H = (K+D) – h + N H = (K+D) – (h + N)

• negative H indicates height of terrain above sea level

• positive N indicates geoid above ellipsoid

•negative H indicates height of terrain above sea level

•negative N indicates geoid above ellipsoid

GPS Heighting at Marine Areas

3.03.0RESEARCH RESEARCH METHODOLOGYMETHODOLOGY

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• Tide gauge• Geoid

4.04.0PRELIMINARY RESULTSPRELIMINARY RESULTS

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The expected results are:– Map of 3D seabed topography using geoid as vertical

datum– Contour map and DEM of seabed topography– Analysis and comparison of generated seabed topography

using geoid based and chart datum as the vertical datum– A database system for geoid based vertical height datum

5.05.0CONCLUSIONSCONCLUSIONS

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• The geoid can be used also in marine areas to be the vertical datum as well as inland.

• Land and marine has the same vertical datum which is geoid.

6.06.0REFERENCESREFERENCES

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Mohd Syahrul Syahrin Bin Hamdan (2006): Analisis Kaedah Penentuan Ketinggian Ortometrik GPS Menggunakan Model Geoid. Universiti Teknologi Malaysia, Tesis PSM.

EM 1110-1-1003, (2003). Engineering And Design - NAVSTAR Global Positioning System Surveying., http://140.194.76.129/Publications/Eng-Manuals/Em1110-1-1003/C-5.Pdf

Shahrum, Ses., Abdul, Majid, A. Kadir., (1993). Nota Kursus Geodesi Asas, Fakulti Ukur,

Universiti Teknologi Malaysia National-Geospatial Intelligence Agency, (2010). Coordinate Sysytems Analysis: Definition.

http://Earth-Info.Nga.Mil/Gandg/Coordsys/Definitions.Html M. Razali, Mahmud., Rusli, Othman., A. Shahlan, Mardi., Usmuni, Din., (2008). Monograf

Hidrografi Asas. Fakulti Kejuruteraan Dan Sains Geoinformasi, Universiti Teknologi Malaysia.

Seksyen Geodesi., Bahagian Pemetaan JUPEM, (2005). Seminar Rtknet Dan Peta Geoid, Kuala

Lumpur – 12 May 2005, JUPEM. David Dodd, Jerry Mills, Dean Battilana, Michael Gourley, (2010). Hydrographic Surveying

Using The Ellipsoid As The Vertical Reference Surface, FIG Congress 2010 Facing The Challenges – Building The Capacity, Sydney, Australia, 11-16 April 2010

http://earth-info.nga.mil/Gandg/Coordsys/Definitions.Html


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Khairul, A. Abdullah, (1995). Improving The Heights Derived From Geoid Models Using A Regression Model. Universiti Teknologi Malaysia.

Pekeliling KPUP Bil. 10, (2005). Garis Panduan Penggunaan Model Geoid Malaysia (Mygeoid).

Pekeliling Ketua Pengarah Ukur Dan Pemetaan Bil. 10 Tahun 2005 Syazwan, S., (2008). Aplikasi Mygeoid Dalam Kejuruteraan Marin, Tesis PSM, Universiti

Teknologi Malaysia. Nazan, Yilmaz., Celalettin, Karaali., (2010). Comparison of global and local gravimetric geoid

models in Turkey, Scientific Research and Essays Vol. 5(14), pp. 1829-1839, 18 July, 2010 Karaali, C., Berber, N., (2005). Geoid and importance in Geodesy. Turkey National Geodesy

Commission 2005 Scientific Meeting, Workshop Geoid and Vertical Datum, (in Turkish), pp. 314-316.

Ahmad Hilmi Bin Mohamad Idris, (2009). Determination of local geoid using geometric

method: case study at klang valley. Thesis PSM, University Teknologi Malaysia.

Vanicek, P., Kleusberg, A, (1987). The Canadian Geoid-Stokesian Approach, pages 86-98, Manuscripta Geodaetica, volume 12, number 2.


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Fotopoulos, G., (2003). An Analysis on the Optimal Combination of Geoid, Orthometric and Ellipsoidal Height Data, PhD Thesis, University of Calgary, Department of Geomatics Engineering, Canada

Heiskanen, W., A., Moritz, H., (1967). Physical Geodesy. W.H. Freeman and Company San Francisco Dursun, Z., Seker, Abdullah, Yildirim., (2002). Orthometric Height Derivation from GPS

Observations. FIG XXII International Congress Washington, D.C. USA, April 19-26 2002 Azhari, M., Shahrum, S., Majid, K., (2001). GPS As A Tool For Continuous Monitoring of Tide Gauge.

Faculty of Engineering and Geoinformation Science, Universiti Teknologi Malaysia. Wan Abdul Aziz Bin Wan Mohd Akib, (2010). Towards A Redefinition Of The National Geodetic

Vertical Datum By The Integrated Geodesy Adjustment. Jabatan Geodesi Dan Astronomi Fakulti Ukur Universiti Teknologi Malaysia. http://Eprints.Utm.My/5130/1/Towards.Pdf

Vaníček, P., Krakiwsky, E., J., (1986). Geodesy the Concepts. North-Holland, Amsterdam. B., Erol, R., N., Çelik, (2010). Modelling Local Gps/Levelling Geoid With The Assesstment Of Inverse

Distance Weighting And Geostatistical Kriging Methods Itu, Civil Engineering Faculty, Geodesy Division, 34469 Maslak Istanbul, Turkey.

Samuel, J., Wormley, (2007). Orthometric Height (Msl). Http://Edu-Observatory.Org/Gps/Height.Html

http://edu-observatory.org/Gps/Height.Html

7.07.0GANTT CHART (sem. 1)GANTT CHART (sem. 1)

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No.

ActivitiesWeeks

1 2 3 4 5 6 7 8 9 10

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12

13

14

15 16

1 Finding a topic / /2 Synopsis for

submission/ / /

3 Approval of Title

/ /4 Literature study

& discussion/ / / / / / / / / / / / / /

5 Find out software and research area

/ / / / / /

6 Find out data format

/ / /7 Method of data

collection/ / / / / / /

8 Prepare proposal / / / / / / /9 Submit proposal /

10 Presentation /

7.07.0GANTT CHART (sem. 2)GANTT CHART (sem. 2)

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No. ActivitiesWeeks

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

1 Preparation fieldwork

/ /2 Data observation / / /3 Data processing / / / / / / /4 Data management / /5 Result and

analysis of data/ / / / / / / /

6 Report writing / / / / / / / / /7 Submit final draft / /8 Presentation in

seminar (viva)/ /

9 Submit final thesis

/

psm1 - geoid based seamless vertical datum for marine cadastre application

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