Garis Panduan Mengenai Sistem Rujukan Koordinat Di

Rujukan Kami: JUPEM 18/7/2.148 Jld. 3 ( 17 )
Tarikh:
25 Mei 2009
Semua Pengarah Ukur dan Pemetaan Negeri
PEKELILING KETUA PENGARAH UKUR DAN PEMETAAN
BILANGAN 1 TAHUN 2009
GARIS PANDUAN MENGENAI SISTEM RUJUKAN KOORDINAT
DI DALAM PENGGUNAAN
GLOBAL NAVIGATION SATELLITE SYSTEM (GNSS)
BAGI TUJUAN UKUR DAN PEMETAAN
1.
TUJUAN
Pekeliling ini bertujuan untuk memberikan garis panduan mengenai
sistem rujukan koordinat dalam kontek penggunaan Global Navigation
Satellite System (GNSS) bagi kerja-kerja ukur dan pemetaan di
Malaysia.
2.
LATAR BELAKANG
2.1
Sistem rujukan koordinat Malayan Revised Triangulation 1948
(MRT48) dengan Bukit Kertau sebagai titik asalan (origin) telah
digunakan bagi aktiviti pemetaan dan ukur kadaster sejak tahun
1948 di Semenanjung Malaysia. Datum rujukan geodetik bagi
sistem ini adalah Datum Kertau yang menggunakan elipsoid
Modified Everest (Kertau). Bagi Sabah, Sarawak dan Labuan
pula,
aktiviti ukur dan pemetaan telah dijalankan dengan
1
menggunakan sistem rujukan koordinat Borneo Triangulation
1968 (BT68) dengan Bukit Timbalai sebagai titik asalan. Datum
rujukan geodetik bagi BT68 adalah Datum Timbalai yang
menggunakan elipsoid Modified Everest (Timbalai).
2.2
Penggunaan teknologi GNSS bagi kerja-kerja ukur dan pemetaan
di Malaysia telah bermula sejak tahun 1989. Dalam hal ini,
Jabatan
Ukur
menghasilkan
dan
Pemetaan
sistem-sistem
Malaysia
rujukan
(JUPEM)
koordinat
telah
dengan
menggunakan teknik Global Positioning System (GPS), iaitu
Peninsular Malaysia Geodetic Scientific Network (PMGSN94)
pada tahun 1994, diikuti dengan East Malaysia Geodetic
Scientific Network (EMGSN97) pada tahun 1997.
Seterusnya
dalam tahun 2003, kerangka rujukan geodetik GPS pasif tersebut
telah
diperkukuhkan
bagi
menghasilkan
Malaysia
Primary
Geodetic Network (MPGN2000).
2.3
Dalam pada itu, antara tahun 1998 dan 2008, JUPEM telah
membangunkan rangkaian-rangkaian GPS/GNSS aktif, iaitu
Malaysia Active GPS System (MASS) antara tahun 1998 dan
2001 dan diikuti dengan penubuhan Malaysia Real-Time
Kinematic GNSS Network (MyRTKnet) antara tahun 2002 dan
2008.
2.4
Bagi memenuhi tuntutan semasa yang menjurus kepada
penggunaan datum rujukan global yang bersifat geosentrik,
JUPEM telah selanjutnya melancarkan datum rujukan geodetik
baru yang seragam bagi kerja-kerja ukur dan pemetaan di
Malaysia pada 26 Ogos 2003. Datum ini dikenali dengan nama
Geocentric Datum of Malaysia (GDM2000), di mana elipsoid
rujukan adalah Geodetic Reference System 1980 (GRS80). Titik
asalan bagi sistem-sistem rujukan koordinat yang berasaskan
GDM2000 ini adalah di pusat jisim bumi (geosentrik).
2
2.5
Pada tahun 2004 dan 2005 telah berlaku gempa bumi besar,
masing-masingnya bermagnitud 9.2 dan 8.7 pada skala Ritcher di
Sumatra, Indonesia dan kejadian ini telah menyebabkan anjakan
yang
signifikan
terhadap
sistem
koordinat
GDM2000.
Sehubungan itu, pemantauan anjakan keatas sistem-sistem
rujukan koordinat telah dilakukan oleh JUPEM secara berterusan
melalui analisis anjakan ke atas stesen-stesen MyRTKnet.
Analisis mendapati bahawa sistem-sistem rujukan koordinat yang
berasaskan GDM2000 perlu disemak dan dihitung semula,
terutamanya bagi kerja-kerja pengukuran yang memerlukan
penggunaan sistem rujukan koordinat yang berkejituan tinggi
seperti di dalam bidang geodesi dan geodinamik.
2.6
Hasil daripada semakan dan hitungan semula tersebut yang
menggunakan produk data GPS bermula 1 Januari 2006 hingga
30 April 2009, siri set koordinat baru yang dikenali sebagai
GDM2000 (2009) bagi rangkaian-rangkaian GNSS/GPS aktif dan
pasif telah diterbitkan oleh JUPEM.
3.
GARIS PANDUAN PENGGUNAAN SISTEM RUJUKAN KOORDINAT
Penerangan lebih lanjut tentang amalan penggunaan sistem rujukan
koordinat terkandung di dalam dokumen Technical Guide to the
Coordinate Reference Systems seperti di Lampiran ‘A’ yang disertakan.
Intisari kandungan garis panduan tersebut adalah seperti berikut:
3
Perenggan
Perkara
1.
INTRODUCTION
2.
OLD TRIANGULATION NETWORKS
3.
2.1
MALAYAN REVISED TRIANGULATION 1968 (MRT68)
2.2
BORNEO TRIANGULATION 1968 (BT68)
GPS-BASED NETWORKS
3.1
PENINSULAR MALAYSIA GEODETIC SCIENTIFIC
NETWORK 1994 (PMGSN94)
3.2
EAST MALAYSIA GEODETIC SCIENTIFIC NETWORK
1997 (PMGSN97)
4.
GEOCENTRIC DATUM OF MALAYSIA (GDM2000)
4.1
INTRODUCTION
4.2
MALAYSIA ACTIVE GPS SYSTEM (MASS)
4.3
MALAYSIA PRIMARY GEODETIC NETWORK 2000
(MPGN2000)
4.4
MALAYSIA REAL-TIME KINEMATIC GNSS NETWORK
(MyRTKnet)
5.
REVISION OF GDM2000
5.1
MAJOR SUMATRAN EARTHQUAKES IN 2004, 2005
AND 2007
6.
4.
5.2
MyRTKnet IN GDM2000 (2009)
5.3
MPGN200 IN GDM2000 (2009)
CONCLUSION
PEMAKAIAN
4.1
Sistem-sistem rujukan koordinat yang dinyatakan di dalam
pekeliling ini hendaklah digunakan berdasarkan tarikh-tarikh
tertentu seperti yang dinyatakan dalam Jadual 1 dan Jadual 2 di
bawah:
4
Jadual 1 : Jaringan GPS/GNSS Pasif Malaysia
Sistem Rujukan Koordinat
Bil
Sistem Koordinat
1
Peninsular Malaysia Geodetic
Scientific Network 1994
(PMGSN94)
2
East Malaysia Geodetic
Scientific Network 1997
(EMGSN97)
Datum Geodetik
WGS84
Ellipsoid: WGS84
Reference Frame: WGS84
Epoch: 1987.0
WGS84
Ellipsoid: WGS84
Reference Frame: WGS84 (G783)
Epoch: 1997.0
GDM2000
3
Malaysia Primary Geodetic
Network 2000
(MPGN2000)
Ellipsoid: GRS80
Reference Frame: ITRF2000
Epoch: 2000.0
Tarikh
Penggunaan
1 Januari 1994
hingga
22 Ogos 2003
1 Januari 1997
hingga
22 Ogos 2003
23 Ogos 2003
hingga
30 April 2009
GDM2000 (2009)
Ellipsoid: GRS80
Reference Frame: ITRF2000
Epoch: 2000.0
Mulai
1 Mei 2009
Jadual 2 : Jaringan GPS/GNSS Aktif Malaysia
Sistem Rujukan Koordinat
Bil
Sistem Koordinat
Datum Geodetik
GDM2000
1
Malaysia Active GPS System
(MASS)
Datum: GRS80
Reference Frame: ITRF2000
Epoch: 2000.0
GDM2000
2
Malaysia Real-Time Kinematic
GNSS Network
(MyRTKnet)
Datum: GRS80
Reference Frame: ITRF2000
Epoch: 2000.0
1 Januari 1999
hingga
30 April 2009
12 Mei 2004
hingga
30 April 2009
GDM2000 (2009)
Datum: GRS80
Reference Frame: ITRF2000
Epoch: 2000.0
4.2
Tarikh
Penggunaan
Mulai
1 Mei 2009
Bagi pengguna-pengguna yang terlibat di dalam kerja-kerja ukur
yang memerlukan ketepatan dan kejituan yang tinggi, khususnya
bidang geodesi dan geodinamik, tarikh penggunaan sistem-
5
sistem rujukan koordinat berasaskan GDM2000 adalah sehingga
31 Disember 2005, manakala tarikh penggunaan sistem-sistem
rujukan koordinat berasaskan GDM2000 (2009) adalah mulai
1 Januari 2006.
4.3
Pengguna-pengguna boleh mendapatkan nilai-nilai koordinat dan
maklumat lokasi bagi setiap stesen trigonometri dan stesen
GPS/GNSS dengan menghubungi Ibu Pejabat JUPEM, Kuala
Lumpur atau dengan melayari Laman Web JUPEM, iaitu
http://www.jupem.gov.my.
Selain
itu,
JUPEM
juga
turut
menyediakan maklumat dan perkhidmatan penukaran koordinat
dan transformasi datum bagi semua sistem rujukan koordinat
serta unjuran peta kepada para pengguna.
5.
TARIKH BERKUATKUASA
Pekeliling ini adalah berkuatkuasa mulai tarikh ianya dikeluarkan.
Sekian, terima kasih.
“BERKHIDMAT UNTUK NEGARA”
( DATUK HAMID BIN ALI )
Ketua Pengarah Ukur dan Pemetaan
Malaysia
6
Salinan kepada:
Timbalan Ketua Pengarah Ukur dan Pemetaan
Pengarah Ukur Bahagian (Pemetaan)
Pengarah Ukur Bahagian (Kadaster)
Pengarah
Bahagian Geospatial Pertahanan
Setiausaha Bahagian (Tanah, Ukur dan Pemetaan)
Kementerian Sumber Asli dan Alam Sekitar
Pengarah
Institut Tanah dan Ukur Negara (INSTUN)
Kementerian Sumber Asli dan Alam Sekitar
Pengarah
Pusat Infrastuktur Data Geospatial Negara (MaCGDI)
Kementerian Sumber Asli dan Alam Sekitar
Ketua Penolong Pengarah
Unit Ukur Tanah, Cawangan Pengkalan Udara dan Maritim
Ibu Pejabat Jabatan Kerja Raya Malaysia
Penolong Pengarah
Unit Ukur Tanah, Bahagian Kejuruteraan Awam
Ibu Pejabat Jabatan Perumahan Negara
Setiausaha
Lembaga Jurukur Tanah Semenanjung Malaysia
Setiausaha
Lembaga Jurukur Tanah Sabah
Setiausaha
Lembaga Jurukur Tanah Sarawak
7
Lampiran ‘A’
Technical Guide
to the
Coordinate Reference Systems
JABATAN UKUR DAN PEMETAAN MALAYSIA
2009
TABLE OF CONTENTS
1. INTRODUCTION
1
2. OLD TRIANGULATION NETWORKS
2
2.1
MALAYAN REVISED TRIANGULATION 1968 (MRT68)
2
2.2
BORNEO TRIANGULATION 1968 (BT68)
5
3. GPS-BASED NETWORKS
3.1
3.2
7
PENINSULAR MALAYSIA GEODETIC SCIENTIFIC NETWORK
1994 (PMGSN94)
7
EAST MALAYSIA GEODETIC SCIENTIFIC NETWORK 1997
(EMGSN97)
10
4. GEOCENTRIC DATUM OF MALAYSIA (GDM2000)
12
4.1
INTRODUCTION
12
4.2
MALAYSIA ACTIVE GPS NETWORK (MASS)
12
4.3
MALAYSIA PRIMARY GEODETIC NETWORK 2000
(MPGN2000)
14
MALAYSIA REAL-TIME KINEMATIC GNSS NETWORK
(MyRTKnet)
17
4.4
5. REVISON OF GDM2000
19
5.1
MAJOR SUMATRAN EARTHQUAKES IN 2004, 2005 AND 2007 19
5.2
MyRTKnet IN GDM2000 (2009)
24
5.3
MPGN2000 IN GDM2000 (2009)
25
6. CONCLUSION
26
REFERENCES
27
i
1. INTRODUCTION
1.1 Coordinate reference systems have been established in many regions
around the world by national mapping authorities since the 19th
century, using conventional surveying techniques and procedures.
Most of them use local datums that are confined to small areas of the
globe, fit to limited areas to satisfy national mapping requirements.
This is also the case with Malaysia where it has in place two
old/classical triangulation networks, namely the Malayan Revised
Triangulation 1968 (MRT68) for Peninsular Malaysia and the Borneo
Triangulation 1968 (BT68) for Sabah and Sarawak.
1.2 With the recent advances in space-based positioning technology,
many countries have begun to implement and subsequently adopted a
global geocentric coordinate reference system. In relation to this,
JUPEM itself has embraced in the early 1990s the Global Positioning
System (GPS) technology with the eventual objective of adopting a
global unified datum for Peninsular Malaysia, Sabah and Sarawak.
This later led to the establishment of the Peninsular Malaysia GPS
Scientific Network 1994 (PMGSN94) and East Malaysia GPS Scientific
Network 1997 (EMGSN97), comprising of 238 stations and 171
stations respectively.
1.3 Subsequently, JUPEM established the permanent GPS tracking
stations known as Malaysia Active GPS System (MASS) at the end of
1998, with eighteen (18) stations making up the whole MASS
infrastructure. Coupled with the GPS data obtained from the
International Global Navigational Satellite System (GNSS) Service
(IGS) stations, the coordinates of MASS stations were derived from 4years of continuous GPS data (1999 - 2002). Collectively, these
coordinates represent the basis for the determination of the Geocentric
Datum of Malaysia (GDM2000), which was launched on 26 August
2003.
1
1.4 Between 2002 and 2008, JUPEM further developed a modern active
GNSS network with the latest state-of-the-art technology to establish
the Malaysia Real-Time Kinematic GNSS Network or MyRTKnet. The
new MyRTKnet system is able to provide real-time positioning services
at centimeter-level accuracy to users in the field.
1.5 However, there were significant displacements of positions of the
aforementioned Malaysian geodetic infrastructure as a result of two
major Indonesian earthquakes that occurred in 2004 and 2005.
Nevertheless, due to the relatively stable conditions that followed in the
past four years (albeit still quite unpredictable), JUPEM has taken
further steps to revise the coordinate reference systems, using GPS
data from the years 2006 to 2008 of MyRTKnet and IGS stations. The
resultant coordinates obtained through this endeavour are known as
GDM2000 (2009).
1.6 This technical guide then is produced to give an overview of the
coordinate reference systems that are available in Malaysia and to
assist users in understanding the concept, strategies and procedures
involved in the move towards the adoption of GDM2000 in 2003 and its
subsequent revision carried out in 2009.
2. OLD TRIANGULATION NETWORKS
2.1
MALAYAN REVISED TRIANGULATION 1968 (MRT68)
2.1.1 JUPEM could trace its origin to way back in 1885. The 1880s marked
an important phase with the commencement of widespread
trigonometrical works in various parts of Malaya, including a
triangulation survey in Penang in 1832.
2.1.2 The trigonometrical survey in Perak together with the Penang and
Province Wellesley triangulations as well as Malacca Triangulation
2
(1886 - 1888) laid the foundation for the existing control framework.
This was followed by the commencement of other trigonometrical
surveys in various parts of the country that included Selangor and
Negeri Sembilan.
2.1.3 However, the early works were so inconsistent and of questionable
quality that it was decided to re-observe the principal triangles of the
general triangulation with the object of bringing it up to modern
standards of that time. This triangulation scheme in Peninsular
Malaysia which was completed in 1916 is known as the Primary or
Repsold Triangulation.
2.1.4 The Primary or Repsold Triangulation was later replaced by a new
system known as the Malayan Revised Triangulation 1948 (MRT48).
This was subsequently followed by a lengthy process of additional
measurements and re-computation until 1968, which eventually
resulted in a system referred to as MRT68.
2.1.5 The MRT68 network consists of 77 geodetic, 240 primary, 837
secondary and 51 tertiary stations. It is based on conventional
observations with many of the triangulation points dated as far back
as 1885. The MRT68 has been adopted as a result of the recomputations of the earlier network together with the Primary or
Repsold Triangulation (Figure 1) carried out between 1913 and 1916.
The reference ellipsoid used for MRT68 is in Table 1 below. The map
projection used for mapping in Peninsular Malaysia is Rectified Skew
Orthomorphic (RSO) and Cassini Soldner for cadastral surveying.
Table 2 tabulates the parameters for map projection used in
Peninsular Malaysia.
3
Table 1
No.
Reference Ellipsoids for MRT68 and BT68
Parameter
MRT68
BT68
1.
Reference Ellipsoid
Modified Everest
Modified Everest
2.
Origin
Kertau, Pahang
Timbalai, Labuan
3.
Semi-major axis ( a )
6 377 304.063
6 377 298.556
4.
Semi-Minor Axis ( b )
6 356 103.039
6 356 097.550
5.
Flattening ( f )
1/300.8017
1/300.8017
6.50
G058
G071
G028
G035 G023
G029
6.00
G047
G031
G030
G044
G054
G003
G057
G040
G025
G032
G033
G077
G042
G059
5.50
G027
G076
G019
G021
G017
G063
G048
G026
G013
G069
G050
G060
G072
G016
G053
G008
G022
5.00
G024
G034
G067
G037
G005
4.50
Latitude
G004
4.00
G007
G041
G001
G070
3.50
G075
G074
G061
G036
G073
G009
G011
G015
3.00
G052
G055G065
G068 G038
G020
G066
G039
G012
G010
2.50
G051
G046
G014
2.00
G049
G002
G062
G043
1.50
G084
G045
P075
G056
G018
G064
P4
1.00
99.50
100.00 100.50 101.00 101.50 102.00 102.50 103.00 103.50 104.00
Longitude
Figure 1: Malayan Revised Triangulation 1968 (MRT68)
4
2.2
BORNEO TRIANGULATION 1968 (BT68)
2.2.1 Sabah started its primary triangulation work in a project known as the
Borneo West Coast Triangulation between 1930 and 1942. In around
1935, Sarawak and Brunei also began their primary triangulation
projects.
2.2.2 The Directorate of Overseas Survey (DOS) undertook the task of
readjusting the whole primary triangulation of Borneo. The adjusted
results for the Primary Triangulation of Borneo 1948 were then
published in terms of Timbalai Datum and Modified Everest ellipsoid.
2.2.3 The East Coast Triangulation was later introduced and initiated by
DOS and observations were carried out in the year 1955 to 1960.
The aim of this triangulation was to extend the Primary Triangulation
of Borneo to the eastern side of Sabah. EDM traversings were also
carried out in 1961 to 1968 to supplement the work.
2.2.4 The combined geodetic networks in Sabah and Sarawak, known as
the Borneo Triangulation 1968 (BT68), was established with the
station at Bukit Timbalai (in the island of Labuan) as the origin. BT68
consequently resulted from the readjustment of the primary control of
East Malaysia (Sabah, Sarawak and Brunei) made by the DOS.
2.2.5 The BT68 network consists of the Borneo West Coast Triangulation
of Brunei and Sabah (1930-1942), Borneo East Coast Triangulation
of Sarawak and extension of the West Coast Triangulation in Sabah
(1955-1960) as well as some new points surveyed between 1961
and 1968. This geodetic network is shown in Figure 2 with the
reference ellipsoid used given in Table 1. The map projection
employed for mapping and cadastral surveys is RSO and Table 2
shows the various parameters used.
5
Table 2: Map Projections for Peninsular Malaysia, Sabah and Sarawak
No.
Parameter
Peninsular Malaysia
Sabah & Sarawak
1.
Projection
Name
Malayan RSO
Borneo RSO
2.
Datum
Kertau
Timbalai
3.
Conversion
Factor
1 chain= 20.11676512m
1 chain = 20.11678249m
(Sears, Jolly & Johnson,
(Chaney & Benoit, 1896)
1927)
4.
Origin of
Projection
N 4° 00’ , E 102° 15’
N 4° 00’ , E 115° 00’
5.
Scale Factor
(Origin)
0.99 984
0.99 984
7.0
6.0
SABAH
5.0
Latitude
SOUTH CHINA SEA
4.0
3.0
INDONESIA
SARAWAK
2.0
1.0
110.0
111.0
112.0
113.0
114.0
115.0
116.0
117.0
118.0
119.0
Longitude
Figure 2: Borneo Triangulation 1968 (BT68)
6
3. GPS-BASED NETWORKS
3.1
PENINSULAR MALAYSIA GEODETIC SCIENTIFIC NETWORK
1994 (PMGSN94)
3.1.1 As stated earlier, old triangulation networks such as MRT68 and
BT68 are regional in nature and are thus not aligned with global
geocentric coordinate frames. On the other hand, earth-centered
geocentric system is difficult to define - not until the recent
development of space-based positioning systems. This was made
possible over the last decade or so because the space-based
positioning satellites revolve around the center of mass of the earth
and are therefore related to an earth-centered or geocentric datum.
3.1.2 The World Geodetic System of 1984 or WGS84 is one such system,
which is maintained by the United States Department of Defense for
GPS-based positioning. Another is the International Terrestrial
Reference Frame (ITRF) and it is reported to be compatible with
WGS84 at the centimeter level.
3.1.3 In an effort to harness the full prowess of the space-based
technology, JUPEM has established a GPS network of 238 stations
in Peninsular Malaysia, called the Peninsular Malaysia Geodetic
Scientific Network 1994 (PMGSN94), as in Figure 3. The main
objectives of setting up PMGSN94 are to establish a new geodetic
network based on GPS observations and to analyse the existing
geodetic network. The network has been observed using four
Ashtech LX II dual frequency GPS receivers and the acquired data
was processed and adjusted in 1994.
3.1.4 In the network adjustment, a minimally constrained adjustment was
made with Kertau, Pahang, held fixed. The coordinates of Kertau are
in approximate WGS84 and derived from Doppler coordinates of
NSWC 9Z-2 reference frame. The Ashtech GPS Post-Processing
7
Software (GPPS) with broadcast ephemeris was used for the
determination of the baseline solutions. The relative accuracy of the
network is between 1-2 ppm for the horizontal coordinates and
between 3-5 ppm for the vertical coordinates. The summary of the
results of the network adjustment using Geolab network adjustment
software is tabulated in Table 3.
7.00
6.50
P299
TG38
P298
S136
TG56
DOP5
P296
6.00
P304
P249
P297
P305
DOP4
P243
P808
P306
P307
P289
P290 P292
P288
P309
P308
P225
P246
P240
P238
P241
P236
TG42
P287
P285
TG61
TG28P239
P244
P245
TG31
P247
P809
P291
P314
TG36
P283
P242
P248
TG27
P293
K350
5.50
P250
P295TG35
P310
P277
P235
P311
P282
TG33
P276
P313
P280
P281
5.00
P083
P264
P271
P275 P272
TG26
P278
P223
P221
P279
P237
P232
P224
P222
P286
P263
P234
T283
P233
P107 P251
P231
P252
P106
P230
P253
P265
P220
P273
P105
P267
P274
P254
P229
P270
P214
P209
P204
P205
4.50
P203
P102
P207
P255
P228
P227
P258
GP02
P259
G003
GP26
T200
GP07
GP81
TG13
TG24
GP27
TG25
GP82
T190
GP30
GP04
P226
P260
P201
GP28
4.00
P257
P261
P218
P215
P101
P256
P219
P216
P217
P202
S290P210
P211
Latitude
P500
P268
TG58
P213
TG57
P351
TG59
P212
P352
P269
GP29
TG14
GP79
GP34
GP31
GP45
GP35
GP32
GP33
251.00
GP94
GP25
TG18
GP05
GP06
3.50
GP22
GP24
GP86
GP80
DOP3
GP95
GP17
GP08
3.00
GP99
GP88
GP21
GP87
149B
DOP1
GP37
GP36
TG15
GP23
GP38
TG11
G100
GP19
GP40
GP20
GP39
GP98
TG06
TG01
GP18
GP89
GP09
GP10
TG20
GP41
TG05
GP42
GP43
GP14
2.50
GP11
GP12
GP44
GP13
TG09
GP47
TG04
M331TG03
GP56
GP57
GP61
GP16
GP58
GP55
GP15
GP48
2.00
GP59
GP85
GP60
GP84
GP90
GP54
GP91
13DJ
GP51
GP49
GP53
TG07
GP50
TG19
1.50
J416
TG10
DOP2
GP52
TD01
99.00
99.50
100.00
100.50
101.00
101.50
102.00
102.50
103.00
103.50
104.00
104.50
105.00
Longitude
Figure 3: Peninsular Malaysia GPS Scientific Network 1994
(PMGSN94)
8
Table 3: Results of Minimally Constrained Adjustment for PMGSN94
Network Adjustment Software
Used
Geolab Network Adjustment
Fixed Point in 3D
Kertau, Pahang
Approximate Positions
237
Number of Parameters
711
No. of Observations
3594
Redundancy
2883
Weights Used
σN = 5mm ± 0.5 ppm
σE = 5mm ± 0.7 ppm
σU = 7mm ± 1.1 ppm
Variance Factor Used
0.9952
Chi-Square Test
Passed
Station Error Ellipses
Hort: 0.038 – 0.094
Vert: 0.032 – 0.080
Relative Error Ellipses
Hort: 0.013 – 0.031
Vert: 0.011 – 0.030
Average Baseline Accuracies
Hort: < 1.5 ppm
Vert: < 2.0 ppm
9
3.2
EAST MALAYSIA GEODETIC SCIENTIFIC NETWORK 1997
(EMGSN97)
3.2.1 Following the successful completion of PMGSN94 in Peninsular
Malaysia, JUPEM began making plans to establish a similar type of
GPS-derived geodetic network in Sabah and Sarawak. For this
purpose, GPS observations were made using Trimble 4000SSE
L1/L2 receivers to establish the East Malaysia Geodetic Scientific
Network 1997 (EMGSN97) that comprises a total of 171 GPS
stations as shown in Figure 4.
3.2.2 In the network adjustment, a constrained adjustment was made with
coordinates from the Special Technical Royal Engineer (STRE) GPS
campaign fixed. Broadcast ephemeris was used for the baseline
determinations. The relative accuracy of the network is found to be
better than 1 ppm for the horizontal coordinates and 2-3 ppm for the
vertical coordinates. The summary of the results of the network
adjustment using Geolab network adjustment software is tabulated in
Table 4.
T121
T122
D006
A102
M204
M203
T123
T120
6.50
M201
M202
T119D005
T118
M103
T117
M104
M301
M311
T116
A101
T124
T114 M102 T113
T115
M101
T003
5.50
D001
T101
T110
T100
T111
T002
M105
T112
M501
M502 T102
T006
M312
T127
T128
M406
M504
T103
M415
M414
M422
M417
T109 M418
M423
M421
M420
M413
T108
M508
M507
T001
M424
M419
M317
M416
M505
M506
M511
M315
M316
M313M314
M303
M503
5101
Latitude
M306
T004
M510
T005
4.50
M307
M310
M305
T125
M302
M304
M404
M401
M509
M403
T104
M405
M402 M407
T007
M411
M412
M408M409
M410 T107
T106
D004
D002
T105
T010
4122
4044
T008
T009
4242
8045
3.50
8047
4118
T012
4119
T043
8048
8028
4127
3074
T015
4120
T041
T014
T016
3032
T013
2.50
6008 3010 3021
T040
T017
T021 T020
6052
1019
T034
1.50
T030
T039
T045
T037
D003
6047
T035
1009
7079
T038
7083
T019T018
T036
4114
T042
3046
7086
7085
7084
7080
7082
T022
2200
T032
T031
2038
T029
2011
R027
T026
2015
J01
T025
9900
2005
0.50
110.00
111.00
112.00
113.00
114.00
115.00
116.00
117.00
118.00
119.00
Longitude
Figure 4: East Malaysia Geodetic Scientific Network 1997 (EMSGN97)
10
Table 4: Results of Constrained Adjustment for EMGSN97
Network Adjustment Software
Used
Geolab Network Adjustment
Fixed Points in 3D
Five (5) Stations from STRE
GPS Campaign
Approximate Positions
166
Number of Parameters
498
No. of Observations
1218
Redundancy
720
Weights used
σN = 2mm ± 0.2 ppm
σE = 2mm ± 0.2 ppm
σU = 2.5mm ± 0.5 ppm
Variance Factor Used
0.9600
Chi-Square Test
Passed
Station Error Ellipses
Hort: 0.009 – 0.044
Vert: 0.010 – 0.055
Relative Error Ellipses
Hort: 0.007 – 0.040
Vert: 0.008 – 0.052
Average Baseline Accuracies
Hort: 0.6 ppm
Vert: 0.8 ppm
11
4. GEOCENTRIC DATUM OF MALAYSIA (GDM2000)
4.1
INTRODUCTION
4.1.1 The Geocentric Datum of Malaysia or GDM2000 is the new national
geodetic datum for Malaysia and it replaces the old datum of MRT48
and BT68. It was officially launched nationwide on 26 August 2003.
4.1.2 The development of GDM2000 began firstly by the establishment of
the zero-order network of permanent GPS stations known as the
Malaysia Active GPS System (MASS). This was followed by the
establishment of the Malaysia Primary Geodetic Network 2000 or
MPGN2000 by strengthening the PMGSN94 and EMGSN97
networks via a GPS observation campaign performed at selected
stations to form a connection to the MASS network. Subsequently,
the MASS network is replaced by another network of active GNSS
stations known as the Malaysia Real-Time Kinematic GNSS Network
or MyRTKnet.
4.2
MALAYSIA ACTIVE GPS NETWORK (MASS)
4.2.1 Malaysia Active GPS Network or MASS is a permanent network of
active GPS stations that was established in 1999 and formed a
homogeneous and coherent geodetic infrastructure, covering the
whole of Malaysia. The MASS station’s GPS data were used along
with those from the International GNSS Service (IGS) stations for the
realization of the zero-order geodetic network for Malaysia.
4.2.2 GPS data from seventeen (17) MASS stations (Figure 5) and eleven
(11) IGS stations (Figure 6) from 1999 to 2002 have been processed
to establish the zero-order geodetic network. The eleven (11)
permanent GPS tracking stations of the IGS world-wide network in
ITRF2000 Epoch 1997 were used as fiducial points in the processing
to obtain the MASS set of station coordinates.
12
8
Arau
Latitude
6
Geti
Usmp
Kina
Kual
Sand
Labu
Ipoh
Miri
Tawa
Kuan
4
Bint
Ktpk
Sega
2
Sibu
Kuch
Utmj
0
98
100
102
104
106
108
110
112
114
116
118
Longitude
Figure 5: Distribution of MASS stations
LHAS
SHAO
KUNM
WUHN
PIMO
IISC
GUAM
NTUS
BAKO
COCO
KARR
Figure 6: IGS stations used to derive MASS coordinates in ITRF2000
13
120
4.2.3 The reference IGS station coordinates which are in ITRF2000 at
epoch 1997.0 were transformed to the same epoch as the adjusted
MASS station coordinates, i.e. ITRF 2000 at epoch 2000.00. From
the free network adjustment, the resulting accuracy of the MASS
stations with respect to the ITRF2000 reference frame at epoch
2000.0 is between 9 to 15 mm in the horizontal component and
between 12 to 19 mm in vertical component.
4.2.4 In the heavily constrained adjustment, a specific reference frame in
ITRF2000 was adopted and results indicated that the accuracy of
station coordinates is between 3 to 16 mm in the horizontal
component and between 8 to 13 mm for the vertical component.
Thus, the coordinates of the heavily constrained adjustment was
adopted as the final coordinates in ITRF2000 at epoch 2 January
2000. These new set of coordinates are known as the Geocentric
Datum of Malaysia or GDM2000 and was officially adopted on
26 August 2003.
4.3
MALAYSIAN PRIMARY GEODETIC NETWORK 2000 (MPGN2000)
4.3.1 Following the availability of MASS network in GDM2000 coordinates,
JUPEM carried out further efforts to transform the PMGSN94 and
EMGSN97 networks into the newly adopted datum. Both networks
formed
the
new
Malaysia
Primary
Geodetic
Network
2000
(MPGN2000) and were strengthened by connecting them to the
MASS network. This was achieved by carrying out GPS campaigns
to re-observe thirty-six (36) stations of PMGSN94 in 2000 and thirty
(30) stations of EMGSN in 2002 for a period of 48 hours to form the
strengthening network (Figures 7 and 8). The outcome defines a
new Malaysia Primary Geodetic Network 2000 (MPGN2000) for the
whole of Malaysia (Figure 9) based on the GDM2000 reference
frame.
14
4.3.2 Heavily constrained adjustment with MASS stations held fixed was
made to adjust the observed baseline vectors and obtain the link
station’s coordinates, which conform to GDM2000. The accuracy of
stations in horizontal and vertical components is less than 14 mm.
The adjustment of the MPGN2000 using the old vectors has
eventually achieved the primary target of obtaining 3 cm accuracy
station coordinate, referred to the ITRF2000 Epoch 1 Jan 2000.
ARAU
6.50
P299
GETI
P298
6.00
P297
5.50
P290
USMP
P244
P247
P238
P310
KUAL
P281
5.00
P221
P263
P274
P229
P213
4.50
P102
P255
P219
IPOH
P258
GP28
GP02
4.00
GP32
3.50
KUAN
GP36 GP37
GP24
GP06
KTPK
GP21
3.00
GP98
GP18
GP43
2.50
GP47
M331
Mass Station
GP58
2.00
Main Station
1.50
99.50
GP50
Check Station
100.00
100.50
GP54
GP84
UTMJ
GP52
101.00
101.50
102.00
102.50
103.00
103.50
104.00
Figure 7: Link Stations Distribution in Peninsular Malaysia
15
D006
7.00
D005M202
M309
Kina M111
6.00
T112
Labu T 004
Sand
M305
M302
M424
M416
M503
T006
Latitude
5.00
Miri
T001
M405
M509
TawaM410
MASS Station
4.00
Main Station
T008
4242
Bint
Check Station
3.00
3046
4119
4114
T041
7083
2.00
T021
1009
Kuch
7080
7086
2011
9900
1.00
109.00
110.00
111.00
112.00
113.00
114.00
115.00
116.00
117.00
118.00
119.00
120.00
Longitude
Figure 8: Link Stations Distribution in East Malaysia
Latitude
6
4
2
100
102
104
106
108
110
112
114
116
118
Longitude
Figure 9: MPGN2000 Stations in Peninsular Malaysia, Sabah & Sarawak
16
120
4.4
MALAYSIA REAL-TIME KINEMATIC GNSS NETWORK (MyRTKnet)
4.4.1 Beginning 2002, JUPEM has established a network known as the
Malaysia Real-Time Kinematic GNSS Network or MyRTKnet that
uses a new generation of RTK solution known as Virtual Reference
Station (VRS). MyRTKnet is based on a network of GPS reference
stations continuously connected via tele-communication network to
the control centre, situated at JUPEM headquarters in Kuala Lumpur
(Figures 11 and 12).
4.4.2 By the end of 2008, Malaysia has seventy-eight (78) RTK reference
stations for the network with fifty (50) stations covering the whole
Peninsular Malaysia, apart from fourteen (14) stations each covering
Sabah and Sarawak. The spacing between stations ranges from 30
to 100 km. Each station is equipped with either a Trimble 5700 or a
NetR5 GPS receiver, antenna, power supply and modem to
communicate with the central facility via Internet Protocol Virtual
Private Network (IPVPN) communication infrastructure.
4.4.3 The central facility at JUPEM headquarters in Kuala Lumpur
continuously gathers the information from GPS receivers at all
MyRTKnet stations and creates a living database of regional area
corrections. With MyRTKnet, a virtual reference station will be
established for any single roving GPS user near the survey area. It
also models the spatial errors that limit GPS accuracy through a
network solution and in turn generates corrections for the roving GPS
users to be positioned anywhere inside the network with an accuracy
better than a few centimetres to a few decimetres in real-time. A web
site is also available to enable downloading of GPS data for postprocessing solutions.
17
7.00
UUMK
ARAU
6.50
LGKW
GETI
TOKA
6.00
SIK1
SGPT
5.50
PASP
AYER
SETI
KRAI
GRIK
USMP
KUAL
TERI
BABH
LASA
5.00
GMUS
Latitude
MUKH
PUSI CAME
4.50
PUPK
LIPI
TLKI
SBKB
4.00
CENE
JRNT
BEHR
SRIJ
BENT
PEKN
TLOH
3.50
MERU
UPMSKLAW
BANT
BAHA
3.00
PDIC
MUAD
KROM
SEG1
2.50
MERS
JUML
GAJA
TGRH
PRTS
2.00
SPGR
JHJY
1.50
TGPG
KUKP
99.00
99.50
100.00
100.50
101.00
101.50
102.00
102.50
103.00
103.50
104.00
104.50
105.00
Longitude
Figure 11: MyRTKnet Stations in Peninsular Malaysia
8.00
7.00
KUDA
MRDU
BELU
UMSS RANA
6.00
SAND
TMBN
LAB1 BEAU KENI
5.00
LAWS
TENM
DATU
Latitude
MIRI
TAWA
SEMP
MRDI
NIAH
4.00
BIN1
MUKH
3.00
BELA
SIB1
2.00
KAPI
SERA
SEMA
UMAS
AMAN
TEBE
1.00
0.00
109.00
110.00
111.00
112.00
113.00
114.00
115.00
116.00
117.00
118.00
119.00
Longitude
Figure 12: MyRTKnet Stations in East Malaysia
18
120.00
5. REVISION OF GDM2000
5.1
MAJOR SUMATRAN EARTHQUAKES IN 2004, 2005 AND 2007
5.1.1 On 26 December 2004, 28 March 2005 and 12 September 2007,
three major earthquakes occurred in Sumatra, Indonesia with
magnitude 9.2, 8.7 and 7.9 on the Richter scale respectively. When
these natural catastrophes occurred, three types of motions were
generated:
a) Pre-seismic motion:
earth movement before the earthquake.
b) Co-seismic motion:
earth
movement
at
the
time
of
earthquake.
c) Post-seismic motion:
earth movement after the earthquake.
5.1.2 The earlier two aforementioned earthquakes have generated motions
and caused significant displacements to the geodetic infrastructures
in Malaysia which need to be modelled. The post-seismic motion is
the most difficult to model and the task can only be made after the
velocity and the rotating pole of the motion have been determined.
5.1.3 The co-seismic motion was deduced by comparing the coordinates of
MyRTKnet stations computed using GPS data during the first week
before the earthquake with those during the second week after the
event. Results indicate that the displacement of MyRTKnet stations
due to the co-seismic motion from the 2004 earthquake in Sumatra
was between 1.5 to 17 cm, occurring predominantly in the south-west
direction. Similarly, the results from 2005 and 2007 earthquakes
indicate
displacements
of
between
1.0
to
6.5
cm
and
1.0 to 3 cm respectively, also in the south-west direction.
5.1.4 Figures 13, 14 and 15 show the displacements of MyRTKnet stations
associated with the co-seismic motions from the 26 December 2004,
28 March 2005 and 12 September 2007 Sumatran earthquakes
respectively.
19
Figure 13: Co-seismic motion during the 26 December 2004 earthquake
Figure 14: Co-seismic motion during the 28 March 2005 earthquake
20
Figure 15: Co-seismic motion during the 12 September 2007 earthquake
5.1.5 Consecutively, the rate of the post-seismic motion was also deduced.
This was carried out by comparing the GDM2000 coordinates of
MyRTKnet stations with those computed after the 2005 earthquake
using GPS data from April to December 2005. Results indicate that
the MyRTKnet stations had experienced post-seismic motion from
the two earlier Sumatran earthquakes and moving at a rate of about
8 cm/year in the south-west direction.
5.1.6 Further computation of MyRTKnet station coordinates for the years
2006, 2007, 2008 and 2009 show that their displacement vectors
from the post-seismic motions continuously demonstrate an anticlockwise rotation, thus indicating a possible return to the effect of
tectonic plate motion. These yearly post-seismic motions for the
years 2006 to 2008 are illustrated in Figures 16, 17 and 18.
21
Figure 16: Post-seismic motion in 2006
Figure 17: Post-seismic motion in 2007 (January to August)
22
Figure 18: Post-seismic motion in 2008
5.1.7 The
accumulated
displacement
of
MyRTKnet
stations
from
26 December 2004 until 30 April 2009 is shown in Figure 19. In
carrying out data adjustments, the GDM2000 coordinates of
MyRTKnet stations in Sabah and Sarawak were held fixed, as the
displacement of the coordinates in Sabah and Sarawak were found
to be very minimal.
5.1.8 From the magnitude of the displacements, which range from 1.0 to
25.8 cm, it can be concluded that the resultant displacement of
MyRTKnet stations, as a result of the co-seismic and post-seismic
motions associated with the 2004, 2005 and 2007 Sumatran
earthquakes,
were
significant.
Consequently,
their
GDM2000
coordinates cannot be further utilised for high precision survey and
that they need to be revised.
23
Figure 19: Accumulated displacement of MyRTKnet stations from
26 December 2004 to 30 April 2009
5.2
MyRTKnet IN GDM2000 (2009)
5.2.1 GPS data from seventy-eight (78) MyRTKnet stations and fifty-six
(56) IGS stations in ITRF2005 from 1 January 2006 to 30 April 2009
as well as GPS data from an observation campaign conducted in
January 2009 on three (3) MASS stations (KUCH, BINT and KINA)
were used in the data processing to re-establish the zero order
geodetic network. However, in the case of Sabah and Sarawak, only
thirty-three (33) IGS stations were used as fiducial points in the
processing to obtain the MyRTKnet set of station coordinates. These
IGS stations which are in ITRF2005 at epoch 2007.67 were then
brought to ITRF2000 at epoch 2000.00 using published velocity
models.
5.2.2 Subsequently, the combined adjustment for the aforementioned data
was fixed at epoch 1 January 2000 and the resulting coordinates
named as GDM2000 (2009). Comparison with the original GDM2000
coordinates was then carried out using three parameter Helmert
24
transformation process and results indicate that the RMS fitting for
the coordinates of four (4) reference stations (KUCH, BINT, KINA
and MIRI) were less than one (1) cm in the north and east as well as
in the height components. Other stations saw large displacements
which were possibly caused by the earthquakes or seasonal
environmental effects.
5.2.3 The final combined adjustment, involving MyRTKnet and MASS
stations only, used the 2009 data and employed the original
GDM2000 reference frame as the reference by holding the
coordinates of the four (4) aforementioned reference stations fixed.
With this adjustment, the resulting coordinates of the MyRTKnet
stations were obtained and are labelled as GDM2000 (2009).
5.3
MPGN2000 IN GDM2000 (2009)
5.3.1 Apart from producing MyRTKnet stations in GDM2000 (2009)
coordinates, similar efforts were also made for the MPGN2000
stations. In order to establish MPGN2000 with GDM2000 (2009)
coordinates, it is necessary to firstly ascertain the thirty-six (36) link
stations between PMGSN94 and MASS (refer to Section 4.3.1) in
GDM2000 (2009). This approach requires adjustment to be
performed using the October to November 2000 GPS vectors of
those link stations and ten (10) MASS stations, by fixing them to the
GDM2000 (2009) coordinates of the MASS stations. With the link
stations in GDM2000 (2009), the next step taken is to perform the
adjustment using the GPS vectors of the remaining PMGSN94
stations. Similar process is carried out for EMGSN97 using thirty (30)
link stations (refer to Section 4.3.2).
5.3.2 Results indicate that the coordinate displacement of the MPGN2000
network in Peninsular Malaysia is not linear and displays elastic
properties. In addition, the displacements also differ from one station
to another. Thus, any type of modelling of the actual displacement
25
needs a long period of monitoring in order to produce precise
parameters. As an alternative, a multiple regression model was
subsequently produced to provide a relationship between the
MPGN2000 in GDM2000 and MPGN2000 in GDM2000 (2009). In
order to validate the accuracy of the multiple regression model, GPS
observations were carried out at selected MPGN2000 stations and
results showed that the coordinates of MPGN2000 in GDM2000
(2009) stations are at cm-level accuracy.
6. CONCLUSION
6.1 JUPEM has successfully established both active and passive GNSS
networks to replace the old triangulation networks in Malaysia. These
new networks will facilitate the development and enhancement of
various surveying and mapping activities and meet the requirements of
all types of users, ranging from the novice to the scientists.
6.2 The GDM2000 supersedes the classical geodetic datums in Malaysia
and has been established with respect to a geocentric reference frame
defined in ITRF system at ITRF2000 epoch 2 January 2000 at an
accuracy of 1 cm. On the other hand, with the reference frame and
epoch maintained, the new GDM2000 (2009) coordinates have taken
into account the displacements and movements resulting from the
Sumatran
earthquakes
in
2004,
2005
and
2007.
This
new
GDM2000 (2009) would be continuously maintained and managed
through the use of MyRTKnet permanent tracking stations to ensure
the availability of a highly accurate, homogeneous and up-to-date
datum for Malaysia.
26
REFERENCES
Abu et al. (1998), Towards the Next Millienium: Current Status, Preliminary
Results and Applications of Malayssian Active GPS System), Paper presented
at the Directors of Surveys Conference, Kuala Lumpur, October 8-9.
Abu, S. (2002), Determination of Malaysian Geodetic GPS Network in the
ITRF2000, Universiti Teknologi Malaysia
Abu, S & Mohamed, A.B. (1997), Sea Level Monitoring System (Proposed
Malaysian Active Control System), Paper presented at the Departmental
Management Meeting, Riviera Bay Resort, Melaka, July 21-22.
Altamimi, Z., P. Sillard, and C. Boucher (2002), ITRF2000: A new release of the
International Terrestrial Reference Frame for earth science application, J.
Geophys. Res., 107(B10), 2214,doi:10.1029/2001 JB000561.
Bitwise Ideas Inc. (1998), Geolab 3.9 Reference Manual, 89 Auriga Drive
Nepean, Ontario Canada
Bowring, B.R. (1985), The accuracy of geodetic latitude and height equations,
Survey Review 28(218): 202-206.
Burford, B.J. (1985), A further examination of datum transformation parameters
in Australia The Australian Surveyor, vol.32 no. 7, pp. 536-558.
Bursa, M. (1962), The theory of the determination of the non-parallelism of the
minor axis of the reference ellipsoid and the inertial polar axis of the Earth, and
the planes of the initial astronomic and geodetic meridians from observations of
artificial Earth Satellites, Studia Geophysica et Geodetica, no. 6, pp. 209-214.
Defence Mapping Agency (DMA), (1987), Department of defence World
Geodetic System 1984: its definition and relationship with local geodetic
27
systems (second edition). Technical report no. 8350.2, Defence Mapping
Agency, Washington.
Department of Survey and Mapping Malaysia, 2000, Malaysia Reference
Frame System: Current Study and GDM2000 Revision (Sistem Kerangka
Rujukan: Kajian Semasa dan Semakan GDM2000).
Department of Survey and Mapping Malaysia, 2007, Malaysia Reference
Frame System: Current Study and GDM2000 Revision (Sistem Kerangka
Rujukan: Kajian Semasa dan Semakan GDM2000).
Directorate of Colonial Surveys, 1948, Primary Triangulation of Borneo
Directorate of Colonial Surveys, 1968, Report on the Adjustment of the Primary
Control in East Malaysia and Brunei
Heiskanen and Moritz (1967), Physical Geodesy, W. H Freeman and
Company, San Francisco, USA.
Hamid Ali, Ahmad Fauzi Nordin, Samad Abu, Chang Leng Hua (2006),
MyRTKnet: Get Set and Go, Coordinates, Issues 6, 6-13
Hugentobler, U., Schaer, S., and Fridez, P. (2001), Bernese GPS Processing
Software Version 4.2, Astronomical Institute University of Berne, Switzerland.
Jamil, H et al (2002), Geocentric Datum of Malaysia, 4th Malaysia Survey
Congress, Subang aya, June 13-14.
Krakiwsky, E.J. and Thomson, D.B. (1974), Mathematical models for the
combination of terrestrial and satellite networks, the Canadian Surveyor, vol.
28, no. 5, pp. 606-615.
Richardus, Peter, and Adler, R. K., (1974), Map Pprojetions for Geodesists,
Cartographers and Geographers: Amsterdam, North-Holland Pub. Co.
28
Rothacher, M., and Mervart, L. (1996), Bernese GPS Processing Software
Version 4.0, Astronomical Institute University of Berne, Switzerland.
Shahabuddin (1978), Msc Thesis, University of Oxford, United Kingdom.
Simons W. J. F., A. Socquet, C. Vigny, B. A. C. Ambrosius, S. Haji Abu,
Chaiwat Promthong, C. Subarya, D. A. Sarsito, S. Matheussen, P. Morgan, and
W. Spakman (2007), A decade of GPS in Southeast Asia: Resolving
Sundaland motion and boundaries, J. Geophys. Res., 112, B06420,
doi:10.1029/2005JB003868
Simons W.J.F., D.L.F. van Loon, A. Walpersdolf, B.A.C. Ambrosius, J. Kahar,
H.Z. Abidin, D.A. Sarsito, S.H. Abu, and P. Morgan (2000), Geodynamics of
S.E. Asia: Final Results of the Sulawesi 1998 GPS campaign, IAG: Geod.
Beyond 2000, 121 271-277
Snyder, J.P. (1984), Map projections used by the U.S. Geological Survey.
Geological Survey Bulletin 1532, U.S. Geological Survey.
Wolf, H. (1963), Geometric connection and re-orientation of three-dimensional
triangulation nets. Bulletin Geodesique. No, 68, pp165-169.
29