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The development of national topographic and cartographic data bases for geographical information system (GIS)implementation in Malaysia

Marzuki Mohd. Kassim, Rosly Abdul Kadir
Department of survey and mapping Malaysia


Abstract
Topographic map data in digital form presents an enormously useful database for the development of Geographical Information Systems (GIS). The ongoing development of the national topographic and cartographic databases in the Department of Survey and Mapping Malaysia (DPNM) would go a long way to meet this requirement.

This paper describes the CAMS base structure for the national topographic map series at the scales of 1:50,00 and 1, 25,000, now under development. in the opening chapter, the paper deals with the production concept and operational strategies of the Computer Assisted Mapping System (CAMS). Lastly some fundamental views are presented on the need for a comprehensive one common database towards the implementation of GIs in Malaysia.

Background
The Development of Survey and Mapping Malaysia is responsible for the production of topographic maps of Malaysia at various scales for civilian and military requirements. Approved under the fifth Malaysian plan (1986-1990), in 1988 the Department of Survey and Mapping Malaysia (DPNM) acquired an automated mapping system called Computer Assisted mapping System (CAMS) with the objective of expediting map production capacity.

Stringent tests were commissioned by the Department of CAMS, which includes the Equipments, System and Functional Tests, and followed by the Provisional Acceptance Test which was completed in the month of Jun1 989. The Department is in the stage of 'Final Acceptance Test' to ensure that the system functions according to the desired specifications and fulfilling the required production rate. CAMS is envisaged to be fully operational by the end of 1989.

CAMS Objectives
The adoption of an automated mapping system introduces significant impact on activities such as data acquisition, storage and retrieval manipulation and generation of output (maps), which could be managed efficiently and accurately. However, CAMS are implemented with the following objectives.
  • To expedite map production capacity of the National Topographic Mapping Series of L7030 and T738 of scale 1:50,000 from the rate f 20 to 50 sheets per year, commeasuring with an idea map revision cycle period.
  • To facilitate the production of maps at various scales and preparation of special maps of civilian and military use.
  • To create national topographic and cartographic data bases at the scales of 1:50,000 and 1:25,000
CAMS Concept of production
CAMS is designed to automate aerial triangulation, the photogram metric compilation and the manual cartographic draughting techniques. CAMS comprises four components namely: Computer Assister Phtogrammetric Subsystem (CAPS), Computer Assisted Cartographic Subsystem (CAS) and the Management Information Subsystem (MIS). Each of the subsystem operates on a standalone module, that is off line to the other subsystems. Data transfer between the various subsystem is via shared disk and magnetic tape. The Functions of the various subsystems are as follows: -
  1. Computer Assisted Photogrammetric Subsystem (CAPS)

    2. The acquisition of digital data from aerial photographs utilizing stereo plotters fitted with rotary encoders and Stereo Track Digitizing System.

  2. Computer Assisted Raster Digitizing Subsystem (CARDS)

    3. The acquisition of digital data from existing maps through scanning and digitizing.

  3. Computer Assisted Cartographic Subsystem (CACS)

    4. Editing of data received from CAPS, CARDS and Field Survey towards the creation of Topographic and Cartographic data bases of scales 1:25,000 and 1:50,000 respectively, and to produce reproduction materials conforming to the map specifications series L7030 and L8028.

  4. Management Information Subsystem (MIS)

    5. MIS caters for Comprehensive Management System to facilitate controls over all aspects of map production, exchange of digital feature coded map data, management of map store and enquiry of CAMS data base.
Data acquisition and editing
Primarily data acquisition is performed utilizing photogram metric and digitizing technique in the CAPS and CARDS, while data editing is performed in the CACS units.
  1. Data Acquisition - Photogrammetric Technique

    2. Aerial photographs are the basic data source of data input. Data acquisition utilizing photogrammetric techniques involves two major steps. The first step is the so-called Aerial Triangulation by which supplement by which supplemental mapping controls are provided. The second step is concerned with the actual data collection of features from aerial photographs, referred to as the process of stereo compilation.

    1. Aerial Triangulation

      2. Aerial triangulation utilizes a semi-analytical process, which comprises the following procedures: -

      • Identification of the available ground and supplemental control points in the aerial photographs.
      • Transferring of the control points on photographic materials utilizing WILD PUG4 point transfer device.
      • Photo coordinates measurements, utilizing stereo metrograph fitted with rotary encoders and stereo track digitizing system.
      • Refinement and compensation for systematic errors and final preparation for the data processing and adjustments utilizing stereo track Digitizing system (model formation and connection).
      • Control data processing and adjustment, which includes the analytical photogrammetric processing to determine the coordinates of the supplemental control as well as other photograpmmetric parameters utilizing PAT-MR block adjustment program.

    2. Stereo Compilation

      3. Stereo compilation involves the digitization of topographic features at the scale of 1:25,000 utilizing Kern PG2 and Wild B8 stereo plotters, fitted with rotary encoders and stereo track digitizing system. The procedures are as follows :

      • Stereo model set up by applying the photogram metric process of inner, relative and absolute orientation, utilizing stereo track digitizing system which run on microcomputer PC-XT (IBM Compatible).
      • Each feature digitized is coded in accordance to the Malaysian appropriate level in the data base.
      • Digital data files are produced for each stereo model containing coded coordinates adapt for both planimetric and/or topographic features.
      • This data files are then transmitted to VAX mainframe computer which support all the interactive graphic system for editing and final preparation processes.Verification plot utilizing calcomp plotter is produced for monitoring and verifying the collected data accurately defines the map features.
      • Adjacent model are then joined, edited and clipped on VeRa 360 workstations utilizing GINIS 300 (Interactive editing and digitizing software) to produce clean digital.
      • Field completion plots consisting of a composite plot and various layers such as back, road, color, height, name and traverse tracings, for field validation by the topographic division.

  2. Data Acquisition - Digitizing Technique

    3. Digitizing techniques involves two major processes, that is, automatic and manual digitizing. In automatic digitizing, digital data are collected utilizing the raster scanner (Kartoscan), while in manual digitizing map features are traced on a digitizer table with tracking device.

    1. Automatic Digitization (Raster Scanning)

      2. In automatic digitizing, the Kartoscan raster scanner is used to convert graphic data into digital data in raster format. This raster data structure takes the shape of a metric of one and zero element representing the black and white areas on the map respectively.

      • Raster data are concerted into vector form by a vectorising program (Raster-to-vector conversion software) utilizing several options provided by the softare depending upon the type of data to be processed.
      • In cases where contour lines are originally in imperial unit, conversion to metric unit is necessary. This is done by first tagging the original contour values using VeRa 540 workstations and subsequently interpolated by menus of the Raster Digital Terrain Model (RDTM) package to produce new contour liens in metric.
      • The vectorized data are then edited and structured according to the Malaysian Standard Digital Feature Code utilizing GINIS (Graphic Interactive Information System) of VeRa 360 workstations.
      • Field completion plots consisting of a composite and various layers such as black, road, color, height, name and traverse tracings are prepared for field validation.

    2. Manual Digitization

      3. Manual digitizing utilizing Computer Aided Digitizing package (CADIG) on VeRa 110 workstations is carried out to supplement data collected through scanning. The digitization procedures are as follows: -

      • Digitization is performed by simply moving the tracking device over each point to be recorded. Upon the operator, command, the planimetric coordinates of each point are sensed and recorded automatically.
      • The process continues to digitize the necessary points forming vectors (consisting of a pair of points) and lines (consisting of a sequence of vectors). Features are digitized according to their appropriate levels.

  3. Data editing - Cartographic Enhancement

    4. Map data collected from CAPS and CARDS and subsequently from field completion from the core of the raw map database. The raw database is further restructured into their appropriate levels according to Malaysian Standard Feature codes and eventually edge-matched to connect border liens. This then forms the accurate maps base, which will be used for subsequent data retrieval and exchange.

    For the production of printed maps, the topographic maps obtained above are further enhanced and generalized, whenever necessary to produce printed maps with color separations for map production. The enhanced maps will form a set of cartographic database only for the purpose of map production. The color separations are then over layed to form a complete printed map. The editing procedures are as follows: -

    • Field data are added to the cartographic data files from CAPS and CARDS, which will be interactively edited for final cartographic output.
    • The additional information is added trough manual digitizing utilizing CADIG and latter interactively edited.
    • Interactive editing utilizing GINIS on VeRa 544/540 involves error detection and corrections of data and the upgrading of data files. The standard editing functions include joining of liens, clipping and manipulations of text and symbol descriptions, some of which will involve moving locations, changing size and rotations.
    • The data processing will then follow for the manipulations of data for input into the final display unit. Data manipulations include the specific task of data reformatting, metric transformations, generalizations, exaggerations and data reductions.
    • Cartographic data files at the scale of 1:25,000 and 1:50,000 in various layers such as black, blue, green, red, brown, X-mask and Mask are then created for plotting on high precision flat-bed plotter in preparation for the final printing.
CAMS database
The CAMS database is a hierarchical model, however, the data base s handle through a network nature, which could handle complex and dense data, due to the nature of internal pointer. The data base stores vector geometry with full structured intelligence capable of distinguishing geometry into distinct groups of feature codes and subgroup or even to a single distinctive type of feature. Its hierarchical model is best suited for map data, which is free-structured in nature and hence make data manipulation and display very easy. Each geometry is represented by a unique address, which can be directly accessed. Each geometry or element has parameters, which tells the characteristics such as line types, symbols, colors etc. The free storage management mechanism present in the database handled automatic extension of disk space whenever required. Whereas two are sharing lien or more features or levels, the data base only stores a single vector line, thus making it coherent eliminating duplicate storage.

CAMS will produce two types of databases, that is, Topographic and Cartographic databases. Topographic databases are at the scale of 1:25,000 while the cartographic database is at the scale of 1:25,000 and 1:50,000. The data are structured into eight (8) main layers comprising of boundary, building, relief, transportation, hydrographic, vegetation, utility and miscellaneous layers.

All the features under this categories are features coded using the Malaysian Standard Digital Feature coded published in 1987. This standard provided the specification for a simple and unstructural means by which the Department and other Agencies may exchange digital data or

Incorporate other land related information from the other agencies or department into their respective database. This lead to one complete, accurate and common Data Base, which can be accessed and used by the Department and other agencies. Brief descriptions of CAMS data base stricture are as follows: -
  1. Boundary Layer

    2. This layer is designed to include the boundary lines of international boundaries with neighboring countries (Land & Maritime), states, reserved and land scheme. Country and state boundaries are described as area enclosed by boundary lines and boundary lines are defined as to types and features identification where the lien corresponds to a physical features such as river, watershed etc

  2. Building Layer

    3. This layer comprises of all features under building, which include Religion, Government, Town and build-up area, commercial. Building generalizes, cultural, building and rural area, Industrial and other buildings. Buildings are described as symbol as sequence of points.
  3. Relief layer

    4. This layer contained all basic elevation data for the CAMS database. These data represent the third dimension of the real world which are graphically presented as contour lines, features related to relief (sin as cliff, cutting, embankment etc). and spot height on topographic maps.
  4. Transport layer

    5. This layer contained primary elements of the Malaysian Transport network including railways, roads, other transportation and features related to transport. Roads are categorized into footpath, motorable, highway, carriageway, unsealed surface, road under construction and features related to road. Transportation features will be defined as line symbols with nodes and the liens will be associated with feature classifications.

  5. Hydrography layer

    6. Hydrography layer includes all perennial and intermittent natural and manmade hydrologic features such as rivers and canal or drain greater in length than 150m and perennial open water where the smallest dimension is 15m. Hydrographic features are defined as line segments and nodes, described by type, implied flow direction by symbol and text. Open water or natural hydrographic features will be defined as areas described by boundary lines consisting of land / water interface and text. Manmade features will be defined by symbols.

  6. Vegetation layer

    7. This layer includes all natural and cultivated vegetation grown in Malaysia. These features will be defined areas described by closed polygon consisting of symbols and text. The boundary liens described area of close polygon will represent the vegetation limits.

  7. Utility layer

    8. This layer includes primary elements of the Malaysian utilities network including electricity, telecommunication, pipeline and sewage. Electricity will be categorized into aerial cable line, underground cable, power station and transmission line. Telecommunication will also be further categorized into telecom line, telecom tower, earth satellite, wireless mast and others. Pipeline will be categorized into gas, petrol and water lines. All these features will be defined as series of line segments, that is line symbols with nodes, and the lien symbols will be associates with features classifications.

  8. Miscellaneous layer

    9. Lastly, this layer includes manmade features which does not fall under the above mentioned categories such as concrete wall, cemetery, oil derrick, mining area, riffle range, archeological feature and fence, cemetery will be further classified into Muslim, Hindu, Christian and Chinese. All these features will be defined either by line symbols or symbols, and some of them will be annotated by text. Examples of CAMS data base layers are show in Appendix A.
Consideration towards the need for a common database
The concept of information management of requirement for system planning that transcends the traditional approaches to the acquisition pf hardware for data processing strategy; unrelated system has been developed on ad-hoc basis by various Government Agencies. Recognising that is a raw resource, expensive in its requisition and in some cases, non-renewable, consideration must therefore be given to the maximization of its use and availability while protecting it from water or loss. Thus a common data base, centralized or distributed, should be implemented to attain the desired attributes as follows:
  • Compatibility of the data to all the available systems
  • Data linkages to all the Departments and other Land Related Agencies (Digital Data Exchange).
  • Data is guaranteed up-to-date, correct and accurate.
  • No duplication and redundancy of effort in capturing basic data.
  • Availability of data to all the Departments and other land related agencies.
It is visualized that data from CAMS data base should be the basic data that can be utilized by other departments and land related agencies in establishing their respective data based for GIS implementation. The agencies.
  • Superior in accuracy compared with other methods of data collection.
  • More flexible in the choices of features to be digitized according to the user's needs.
  • Able to update information and add to the collected data when necessary.
  • More flexible especially in the choices of difference scales of data bases,
  • National coverage with data meeting national map accuracy standards.
Conclusions
Positive participation by the Department of Survey and Mapping in the field of GIS is foreseen. CAMS is an automated mapping system employing computer technology with emphasis on computer graphic capabilities, and having a mandate to expedite map production capability. It therefore has only limited capability for processing non-graphic attributes. These are differentiate with GIS system that combine graphic capabilities with strong non-graphic attribute linkages allowing complex queries, map overlay, polygon processing and geographic modeling operations. it could then be visualized that the department of survey and mapping will concern more towards dissemination of digital topographic and cartographic data to other land related agencies towards their implementation of GIS. To avoid duplication and redundancy of efforts, CAMS data base is to be used as widely as possible as common national data base.

Acknowledgement
The authors are grateful to Mr. Abdul Majid bin Mohamed, Director General of Survey an mapping, Malaysia, for his invaluable advice and approval. To others, who have in some ways contributed to this paper we are deeply indebted.