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Cadastral reform in Malaysia: A vision to the 2000s

Wan Aziz., Majid. K, Sahrum, S.
Department of Geomatic Engineering
Faculty of Engineering & Geoinformation Science
University Teknologi Malaysia,
81310 Skudai. Johor.Malaysia

Teng, C.B
Geodesy Department
Directorate of Surveying & Mapping,
Malaysia Kuala Lumpur, Malaysia


Introduction
Cadastral surveying aims at defining and guaranteeing legal property boundaries, and determining coordinates of all measured points to give information on the size and nature of land use. The role of a land registration system like the cadastre is specifically regulated by laws and other administrative rules and guidelines for a uniform implementation of the system. It will not be possible to design a cadastral system suitable for any case and any circumstances, especially the socio-economic basic conditions are different from country to country. The different forms of land tenure and the legal situation in this field will give the framework for a cadastral systems and how to carry out its technical features. On the other hand, the political circumstances are dictating the financial and personnel investment in the cadastral system The cadastral system in Malaysia is a system that provide more secure basis for land and property ownership. It consists of the surveying and recording mechanism in describing the cadastral information, for example boundary line (in the forms of bearing and distance), location and area of a given parcel of land (lot). The demarcation and delineation of the boundaries are also part of a cadastral survey aimed at defining the parcels on the ground and securing evidence for the re-establishment of the boundary if the marks disappeared.

The typical surveying technique adopted for the cadastral survey which capable of bearing (direction) and distance measurements is the survey equipment called total station (digital theodolite & electronic distance measuring unit). However, the main drawback of this conventional technique is that it requires intervisibility between control points, and this has restricted the productivity of the surveyed lots. Several drawbacks as well as the great demand for efficient and effective cadastral management have prompted various surveying and mapping authorities in the world (including Department of Surveying & Mapping, Malaysia - DSMM) to study the concept of 'Coordinated-based Cadastral System - CCS', see Boey and Hill, (1995), Barnes, et.al. (1996), McDaid, et.al., (1997) and Wong, K.S., (1999). The CCS means that 'bearing and distance' are derived legally from the final adjusted coordinates. Realising the needs of integrating the cadastral data with other map based information (all forms of spatial information)for GIS applications, the CCS has to be prevailed in the near future. The emphasis of the CCS concept is the geocentric datum, a single projection system for the whole country and the application of least squares adjustment procedure in the distribution of survey errors. At present, DSMM have already implemented the cadastral system in digital environment: Computer Assisted Land Survey System (CALS), Cadastral Database Management System (CDMS), the Computerized Land Registration System (CLRS) and National Infrastructure for Land Information System (NaLIS). Therefore, by implementing the CCS, it will opening up and integrate the benefits from advances of technologies into reality.

Several performance tests have been shown that the GPS technology efficiently provides users precise positions. Nowadays, by using modern GPS techniques such as Rapid-Static, Stop & Go and Real Time Kinematics (RTK), many points can be observed in a relatively short period of time with good accuracy as those obtainable by conventional EDM/Total Station surveying. These can increase productivity, reduce cost and manpower, and at the same time is capable to challenge the cadastre task. Furthermore, for multipurpose cadastre surveys, GPS positioning is a desirable and adequate method for establishing and strengthening the national and regional geodetic networks. Therefore, a move to introduce multipurpose coordinate-based cadastre using GPS technology has been under way in Malaysia, in recent years. One of the main advantage in CCS is that it facilitates the use of rapid spatial data acquisition, storage, processing procedure and management techniques, even though several issues unique to the GPS technology need also be addressed. This paper is concerned with the feasibility for implementing a nationwide Coordinated Cadastral Surveying (CCS) in Malaysia. Here, the performance of the GPS technology under the controlled conditions of the cadastral system is tested.

Triangulation and GPS Networks
Employing GPS surveying requires well-established regional and global geodetic networks. They are essential for the preparation of consistent regional and global spatial data. In our case, the Malaysian Datum (West Malaysia), adopts the Modified Everest ellipsoid as a reference with its origin fixed at Kertau, Pahang. The first national geodetic network known as Malayan Revised Triangulation (MRT) consisted of 70 trigonometrical points which is geometrically connected by 340 observed angles and 2 geoidal distances. The MRT network serves as a main control for surveying and mapping activities in our country, including cadastral survey (e.g. standard cadastral traverses). Unfortunately, some of the triangulation points have been 'destroyed' and/or not well maintained. Thus, for the past 15 years, in conjuction with GPS campaign, the re-establishment and updating of the triangulation trig points have been greatly demanded in Malaysia. The Malaysian Datum is different from WGS84 that GPS employs as the reference frame. While the request for the coordinates referenced to the existing datum are still large, demands for the well-accepted global coordinate systems have been also growing. Therefore, a move to adopt geocentric datum has been underway in various country, including Malaysia because it can provide unified geographical reference frame, Teng, (2001).

In Malaysia, serious precise surveying by GPS has started with the establishment the national 1st. order GPS network in 1992, providing a consistence set of coordinates in WGS84. The network is consists of 238 GPS stations (and 171 stations in East Malaysia) which formed the backbone of the National GPS Network. Since then, GPS surveying has been practiced for various surveying and mapping activities in the country. Current trend indicates that for the most precise, effective, economical and fast applications, some form of permanent GPS network should be established. In order to realize such requirements, DSMM has started establishing permanent GPS tracking stations or Malaysian Active Satellite System (MASS) at the end of 1998. Currently, MASS network is consists of 17 permanent GPS stations over the country for scientific research purposes, (e.g. crustal movement, unified datum, earth rotation parameters, atmospheric studies, etc. This network is known as the Zero Order Geodetic Network and it complies with international standards to provide the highest precision for positioning in Malaysia. The National 1st Order GPS Network has been successfully connected to MASS network and its coordinates referred to the ITRF2000 Epoch 00.0 with an accuracy of 1 to 3 cm. Thus, it will form the backbone for the national adjustment of the existing GPS stations to defined all coordinates in ITRF system. By doing this, the adoption of geocentric datum will definitely lead to a homogeneous national coordinate datum across the country (including East Malaysia). Subsequently, in order to benefit directly from proposed geocentric datum, a new projection (and associated parameters) has to be developed so as to allow the coordinates to be projected directly from control network snd dstum to the plane grid system. However, the new projection should have the characteristics of conformal and also, at the sane time maintaining minimal scale distortion.

Coordinate system and transformation
The national (local) geodetic coordinate system consists, in principle ellipsoidal coordinates at a defined set of points. In practice, the Kertau Datum of the MRT, is defined in terms of only the horizontal components (f, l) of the Modified Everest Ellipsoidal coordinates: there is no explicit definition of the ellipsoidal height, h. Now, the first and fundamental answer that any GPS users requires is the question where am I on the Malaysian topographic map at scale 1:50,000?". The GPS receiver will yield geocentric coordinate system in the reference frame to which the satellite orbits are referred. It will not produce coordinates in the local mapping system. If geocentric GPS coordinates are to be very useful for local system, there has to be a coordinate transformation process (function, algorithms) whose form will depend on local information about the mapping control system and the shape of the geoid. In our case, datum transformation enables us to combine GPS measurements with the existing conventional terrestrial measurements whereby 32 triangulation points (MRT system) are used to determine 6 transformation parameters between MRT and WGS84 system. The parameters are estimated by least squares methods using model Bursa-Wolf transformation model - see Table: 1.

Table 1: Transformation Coordjnate from Geocentric WGS84 to MRT Kertau
Items Transformation Parametes
Dx 379.77603 m
Dy -775.38371 m
Dz 86.60926 m
Rx 2".59674
Ry 2".10213
Rz -12".11377

The existing coordinate systems used for mapping and cadastral survey in West Malaysia is the conformal Rectified Skew Orthomorphic system (RSO) and Cassini Soldner system (CS), respectively. The RSO projection system is also based on the Modified Everest reference ellipsoid while the Cassini Soldner is a plane coordinate system for local cadastral system. The mathematical projection models and associated coefficients for RSO and Cassini coordinate systems can be found in Hotine (1947) and in Richardus and Alber, (1974), respectively. A number of origins have been adopted when establishing local Cassini coordinate system, resulting in each state in West Malaysia using a difference origin.. Since the adjusted GPS coordinates are in geocentric datum, i.e. WGS84, they are need to be transformed into these established local systems. The transformation procedure from global datum to local datum (mapping and cadastral system) involves a lengthy computation steps as followed:
  1. WGS84 to MRT : (f, l, h) global => (f, l, h) local
  2. MRT to RSO : (f, l, h) local => (x, y) local
  3. RSO to CS : (x, y) local => (E,N) local
It should be noted here that the difference system between the RSO system (mapping) and the CS system (cadastral) has resulted in incompatibility as far as digital database is concerned. One of the main objective of the CCS is to study the feasibility of adopting the earth-centred geodetic datum RSO as a nationwide coordinate system for cadastral survey. It will replace the currently anachrosnistic Cassini system for cadastral survey. The concept and the stages of implementation of a 'geocentric' RSO projection system for the whole country, i.e. will not included in this paper.

GPS-based cadastral survey
Nowadays, the precision GPS receivers can provide coordinates which are sufficiently accurate for cadastral purposes in rural areas. More importantly, these receivers offer an opportunity to significantly lower the cost and time typically required for cadastral surveys. But, the most fundamental aspects that have to be considered in this study is 'the GPS practice for the use of GPS in cadastral surveying so that is similar to those that already exist for EDM/total station procedures. This will provide means of ensuring the highest quality practices are adhered to which surveys pertaining to land boundaries and title. Therefore, in designing and testing a GPS methodology for cadastral surveying, the following criteria should be adopted, Barne, et.al. (1996).
  • speed (must significantly outperform current approaches)
  • cost (must significantly reduce current unit survey costs)
  • appropriate (must be within the reach of local surveyors)
  • realistic accuracy (match real needs )
  • simple field operation (data collection must be simple to allow for variable field conditions).
Thus, the GPS cadastral survey will includes:
  • The selection of GPS hardware./software
  • The testing/calibration of the GPS equipment
  • GPS control survey procedures
  • The manners in which the GPS results are processed within a least squares procedure so that the coordinates can be 'derived' without ambiguity.
  1. GPS Calibration Tests
    The GPS system testing/calibration is considered as a prerequisite for proving a competence so that the GPS derived coordinates are of uniformly high quality, i.e. it has 'legal traceability'. In order to fulfill such requirements, a GPS calibration network, consisting of few points, should be established to enable government and private surveyors to calibrate their GPS units (receivers, antennas, firmware and software) by providing a set of accessible points with accurately known coordinates. Thus, it provides the basis for a standard test that can be applied to all GPS receivers. This kind of test will become increasingly important as private surveyors embrace GPS technology and the GPS market expands. In this study, a series of GPS baseline test have been carried out using three (3) dual frequency Leica 300 System at the existing EDM baseline calibaration test site in UTM campus. The EDM test site comprises of 6 pillars separated at specified intervals with the shortest and longest distance of about 10 meters and 900 meters , respectively. The baselines have themselves been calibrated against a standard, and hence can fulfill the requirements of legal traceability of GPS-derived distances. In the calibration test, we have found that the differences between GPS and 'EDM published true values' for pairs of the receivers of less than 10 mm which indicates that the GPS equipment set being used are in good condition.


  2. GPS Network Test
    The GPS network test should also be performed to assure the operation of the GPS instrumentation for the purpose of determining high accuracy relative coordinates. Therefore, prior to any cadastral fieldwork with a particular GPS unit, it must be calibrated against the calibration network. The GPS network test can be carried out on an annual basis or when processing software (new version) and/or firmware (new version) is changed. The test is also the most realistic form of test as it ensures that the results for all inter-antenna distances can be checked. It is recommended that the network should include a minimum of 3 existing 1st. order GPS stations (as published by DSMM) and all stations have sky visibility of at least 90%. The relative accuracy of better than a + bL (in mm) should be adopted in the GPS network test; where a= 5mm, b = 2ppm and L = baseline length in kilometres. In this study, three (3) GPS stations (known coordinates) namely GP12, GP13 and M311 separated about 30 km away, have been used as GPS test network using the dual frequency GPS receivers . All points have been occupied for more than one hour observation span to track a minimum of five GPS satellite with cut off angle 15 degrees. The baseline processing and minimal constraint adjustment is carried out using SKI software in WGS84 system. Subsequently, the coordinate transformation, (i.e from WGS84 => MRT=>RSO => CS) is performed using the procedures outlined in previous section. The results have shown that the difference between the adjusted coordinates and the published coordinates is quite small (about 5 cm). Also, the newly GPS derived distances of two baseline, i.e. GP13-GP12 and GP13 - M331 is within the allowable limits (less than 70mm per 30 km) which also indicates that the GPS equipment set being used are in good condition.


  3. GPS Cadastral Survey Test
    A GPS cadastral survey on the selected areas (sites) were carried out using rapid-static technique. The test survey is divided into two cases:

    CASE (i) A 'new cadastral survey lot' using conventional traverse and GPS observations,
    CASE (ii) Adjacent lots which is comprised of existing standard traverse cadastral.

    The rapid static field observation criteria adopted for both cases is shown in Table: 2.

    Table 2: The Rapid Static GPS Observation Criteria
    ITEMS CRITERIA
    Observation span 10-15 minutes
    Recording Interval 15 seconds
    Number of satellites ³ 5
    GDOP £ 5
    Sky coverage ³ 70 %
    Mask angle 15°

    For CASE (i), the survey were done using three (3) Leica dual frequency GPS receivers with two (2) of them remained at base stations and another one is roving receiver. The survey was planned so that all selected traverse stations were occupied successively by the roving receiver. The calibration is performed in order to ensure the correct operation of GPS receivers, associated antennas and cabling, and data processing software, give high accuracy coordinates results (as described in the previous sections). In CASE (i), a sample GPS cadastral control survey has been carried out in UTM campus. The test survey site is comprised of fourteen (14) traverse stations. The conventional traversing method and GPS observations were carried out to determine the coordinates of the traverse points using total station GTS-7 and Leica 300, respectively. Two (2) GPS base stations BC10 and G11, were used as control points for the traverse survey. These stations were previously connected to the National 1st. Order GPS Network. In the processing step, data from 10-15 minutes observation session has been used. The adjustment is being carried out using SKI software with station BC10 and G11 being held fixed. The resulting coordinates were then being transformed into their corresponding values in local MRT, RSO and CS coordinate systems. The area of the traverse survey is also being computed using the adjusted coordinates (in CS system).

    For CASE (ii), the test area is chosen closed to the existing cadastral standard traverse. The survey area is comprised of six (6) cadastral lots, namely 2290, 2291, 2292, 2294, 2296 and 2298. These cadastral lots have been surveyed in 2nd. class survey requirements. The GPS control observations is being carried by connecting two standard traverses stations, MC858 and MC904. The corresponding CS system for station MC858 and MC904 is (S59902.881, E60183.967) and (S60989.321, E62460.282), respectively. Since, the spacing between the two stations are less than 10km apart, they are very suitable to provide control for the proposed GPS cadastral survey on the selected lots which will be carried out using rapid static technique. Also, these stations were previously 'connected to the National 1st Order GPS Network' via two (2) standard cadastral traverse stations (KGPB and MC793. Again, as for CASE (i), the surveys were done using three (3) receivers with two (2) of them remained stationary at these base stations. One receiver is roving successively to occupy fourteen (14) boundary marks whereby two base stations are used to provide independent check on the resulting GPS coordinates for each boundary marks. The GPS network adjustment has also been carried out in WGS84 using SKI software with stations MC858 and MC904 being held fixed. To make the GPS coordinates meaningful, they are then converted into a locally useful system, i.e. MRT, RSO and CS systems. From the GPS-derived CS coordinates, the distance and bearing between the traverse legs were computed. The next step is to make the comparison between these adjusted coordinates and the corresponding Certified Plan (CP) values. Further exercise has also been done by calculating the area for individual lot and comparing them with their corresponding values shown on the CP.
Results and analysis
The SKI adjustment was performed after the completion of GPS data entry (i.e. after download). For the total station traversing, the input data are in terms of bearings and distances (as in the CASE (i)) using a written Fortran program. The output is in the form of adjusted observations, coordinates and information for statistical analysis. For both cases, a set of adjusted coordinates are compared with their corresponding values, i.e. Total Station Values for CASE (i) and CP values for CASE (ii). The comparison between the two sets of coordinates are sumnmarised in Table: 3 and Table: 4, respectively. Figure: 1 illustrates the differences in distance and bearing between GPS derived-values and the corresponding values of conventional traverse, i,.e. CASE (i), while Figure: 2 depicts the similar output for CASE (ii).

Table 3: The Comparison Between The GPS-Derived Values and Conventional Traverse for CASE (i)
Traverse Station GPS-Derived Coordinate GPS Derived distance (m) Difference in distance (mm) and ratio Bearing from GPSSurvey(° ' ") Difference in Bearing (")
S1 S53461.455
E8818.032
38.228 -31: 12742 68 58 56 -18
S2 S53492.114
E8832.609
33.948 51: 6790 154 34 16 35
S3 S53541.852
E8794.974
62.372 -71 : 8910 217 06 49 11
S4 S53553.423
E8753.775
42.753 21 : 21377 254 18 44 -25
S9 S53608.258
E8727.173
60.947 51 : 12189 205 52 46 42
S8 S53581.259
E8652.287
79.604 -41 : 19901 289 49 34 9
P4 S53631.405
E8631.088
54.443 51 : 10889 202 54 58 -31
P3 S53633.735
E8557.799
73.326 51 : 14665 268 10 45 -8
P2 S53617.900
E8516.448
44.279 61 : 7380 290 57 14 20
P1 S53535.736
E8540.823
85.703 -31 : 28568 16 31 25 14
P5 S53403.972
E8611.438
149.493 31 : 48931 28 11 16 24
P7 S53375.319
E8623.656
31.149 91 : 3461 23 06 38 -16
S6 S53423.843
E8708.093
97.387 51 : 19477 119 53 06 26
S7 S53475.166
E8782.347
90.265 61 : 15044 124 39 06 33

Note :
Computed area for GPS Survey = 44323.82 m2
Computed area for Conventional method = 44335.67 m2
Difference = 11.85 m2


Figure: 1 The differences in distance and bearing for CASE (i)


From Table: 3 and Figure:1, it is apparent that the average difference in distance between the GPS cadastral survey and conventional cadastral survey is less than 3 mm. The minimum and maximum differences in distance is occured at traverse legs S3-S4 and P5-P7, respectively. The linear misclosure is also being computed for the corresponding line. All traverse legs have shown that they are fulfilled the 1st order (class) of the cadastral survey requirement with the exception of traverse legs S1 - S2 and P5 - P7. In our country, we adopted the ratio of better than 1: 8000 as a 1st. class cadastral survey. However, the linear miclosure for the traverse leg S1 - S2 is still within the range of 2nd. Class requirement for cadastral survey (i.e. better than.1: 4000). The traverse leg P5 - P7 shows the lowest accuracy in terms of linear misclosure. This may due to the GPS observational factors (biases) such as multipath, the antenna centering error, atmospheric effect, etc. Similarly, it can be seen that the minimum and maximum values of bearing differences between the GPS survey and the total station methods is -8" and 42", respectively. In general, the results show that for shorter traverse legs, the differences in bearing is quite significant. Furthermore, one may also noticed that the differences in distance and bearing between these two techniques is not consistence due to some biases in GPS observations (e.g. setting errors, multipath), conventional survey values (e.g. Bowditch adjustment) or in the coordinate transformation processes (e.g. coefficients). The area for the test site is also being computed for both the GPS and conventional surveys. The result has shown that there is no significant difference in computed area between areas computed from the GPS coordinates and the conventional traverse (i.e. 0.12%). Therefore, it is believed that the differences of less than 1% could be achieved for lot area of less than 5 hectares.

Table: 4 The Comparison Between The GPS-Derived Values and Conventional Traverse for CASE (i)

Traverse Station GPS-Derived. Distance (m) GPS Derived Bearing(° ' ") Difference in distance (mm) and ratio Difference in Bearing (")
M1-M2 43.828 90 35 07 -3
1:14609
-3
M2-M3 42.494 94 41 57 -2
1:21247
47
M3-M4 27.430 94 42 12 -5
1:5486
-8
M4-M5 121.066 177 14 26 12
1:10088
16
M5-M6 36.972 263 29 37 -5
1:7394
16
M6-M7 37.679 263 28 56 -7
1:5420
26
M7-M8 43.266 263 28 42 8
1:5408
-28
M8-M1 140.501 359 06 29 9
1:15611
39
M2-M7 135.129 179 25 43 8
1:16891
23
M3-M6 127.414 181 36 16 10
1:12741
26
M8-M9 199.275 179 04 45 0 15
M7-M10 200.344 179 13 27 1
51:13356
37
M6-M11 202.000 177 38 56 1
81:11222
36
M5-M14 175.888 177 34 33 -5
1:P35178
43
M9-M10 42.669 84 50 22 -2
1:21335
42
M10-M11 43.098 86 18 41 -9
1:4788
61
M11-M12 30.349 86 18 42 8
1:3794
-88
M12-M13 28.489 356 49 18 -5
1:5698
-22
M13-M14 1.181 90 52 05 3
1:2394
-195


Figure 2 . The differences in distance and bearing for CASE (ij)


From Table: 4 and Figure: 2, it is seen that the difference in distance is less than 2cm, having a minimum and maximum value of 0mm and 18mm for traverse leg M6-M11 and M8-M9, respectively. The overall results show that longer distance between stations (in conventional cadastral traverse) produced a significant distance errors. On the other hand, it seems that the magnitude of errors in bearing (angular measurements) could be large for a shorter distance, see traverse legs M10-M11, M11-M12 and M13-M14. This is due to the fact that for a shorter distance, the pointing errors is quite large compare to longer distance. Also, one may noticed that the differences in distance and bearing between the GPS values and CP values is not consistence thoroughout the traverse legs. Agains, some errors may occured in GPS observations, for example multipath, observational noise, setting errors, and/or errors in coordinate transformation processes (e.g. coefficients), errors in conventional traverse surveys, e.g. theodolite setting/pointing errors, Bowditch adjustment, etc. The size of area for the test site is also being computed for both GPS and conventional surveys, see Table: 5. This table indiactes that in general differences of less than 1 meter squares could be achieved for lot area of less than 1 hectare.

Table 5. Area Comparison Between GPS and CP Values
Lot Number Computed GPS Area
( m2)
Existing Area CP
(m2)
Difference
(m2)
2290 8552 8551 1
2291 8107 8108 -1
2292 7312 7312 0
2294 5985 5985 0
2296 5235 5236 -1
2298 3978 3978 1
Total 39169 39170 -1

The results from this test shows the potential of using GPS (rapid static) in cadastral survey in Malaysia. But, it has to be recognised that in order to use GPS technology for cadastral surveys, GPS measurements must be legally traceable, i.e. calibration procedures, GPS field control survey and office procedures. Apart from this, several aspects should be taken into account for the conception, and this may include the underlying features of a coordinated cadastre as indicated by DSMM and the future direction of the cadastre.

Concluding remarks
The technical design of a cadastral system in a developing country likes Malaysia needs a precise definition of the requirements and aims at such a system. A cadastral system is not a monolithic block. It should be designed to fulfil the changing legal demands and demands of administration and the private sector. Appropriately, it should be able to develop it into a great variety of multipurpose (modern) cadastre and flexibility for planning, environmental protection etc.. Here, it is crucial that a more efficient method of cadastral surveying should be implemented, and that the standards, specification and procedures for cadastral surveying give a high priority to speed, cost and an accuracy level. Also, at the same time, it does not jeopardize the effectiveness of the land registration system. It is therefore, the ' creation' of CCS in Malaysia is a major long-term undertaking which can systematically be implemented either in phased or incremental approach.

The procedures for both GPS test calibration gives a solution which we feel offers legal traceability and quality control checks. However, it is important to remember that the coordinate values are merely evidence as to the "legal" position indicated by the original physical monument.. Also, it should be kept in mind, the GPS method will not work in every situation. Therefore, in order to be effective, it needs to be integrated with current techniques and equipments, for example, using Total stations where GPS doesn't work (under trees or near buildings). One of the shortcomings of the proposed GPS methodology is that it cannot easily be used for setting out new points at predefined locations. Finally, to conclude this paper, we believe that the GPS technology will offer a very viable alternative to cadastral surveying approaches, such as aerial photography or total station techniques, typically adopted in large scale land administration, titling and registration projects.

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