The Development of Location Based Services in Malaysia
2 LITERATURE REVIEW
2.1 Introduction to OpenLS
The main objective of OpenLS is to define access to the core services and Abstract data Type (ADT) that comprises its main technology called geoserver. It enables communication of location, routes, types of service and others, with diversity on technology platforms, application domains, classes of products, carrier networks and national regions. The core services provided by a OpenLS are  :-
The ADT provided by OpenLS is the basic information constructed used by geoserver and associated core services. It consists of well known data type and structure for location information. ADT are defined as application schemas that are encoded in XML for Location Service (XLS). They are designed in a compact form to avoid complexity and are totally extensible. Major benefits of obtaining OpenLS for LBS are:-
- Proximity Search using POI database.
- Location Determination to fetch user location using Open Mobile Alliance (OMA) Mobile Location Protocol (MLP).
- Routing Services for travel routes and navigation.
- Map Rendering to produce maps with a set of Abstract Data Type (ADT) as overlay
- Geocoding and Reverse Geocoding to manipulate address into latitude and longitude or the other way.
The ease of data management provided through OpenLS. Obtaining data from different sources, without having to worry about duplication. This approach is can be realized through web services platforms and XML based protocols.
- To fulfill most of users expectations such as cross cell phone roaming boundaries, where operators may share positioning technology as a support from their own, as well as integrated billing just like the provided by other services.
- Carriers or operators may look forward into an integrated system, and easy migration product which is much more cheaper.
2.2 MyGDI as the Main Source for Geospatial Data
Currently, the implementation of MyGDI through out the world focuses on data collection and updates. Data were gathered by land surveyors and processed according to the standards provided by the government. A set of definitions were use in order to group geographical layers and its tabular data inside the database. So far, an MyGDI plays an effective role of promoting land information sharing. It obviously can avoid wastage of duplicate efforts on data collection and maintenance. MyGDI has emerged as an important bridge among data providers and users to enable data sharing and exchange using the latest online information technology. A concept, which is called data custodianship, which determines that the data custodian holds the responsibility of fulfilling the required standard in ensuring the integrity of their data by taking all necessary measures and plan to manage their data to meet the requirement . Data custodian are mostly government agencies, such as municipal, City halls and others. Data custodians must be responsible for the matters of data collection and maintenance to avoid any duplication. They must ascertain that their data is always available and ready to be accessed. At the same time, they must systematically provide metadata and ensure the format of the metadata complying with the guidelines of provided by the government. Once distributed, GIS users can collect and integrate them in their own GIS applications. Such data sets would provide GIS users with the most up-to-date and highest quality data sets publicly available. Hence the users have to spend only a minimum amount of cost for the core data in their GIS applications.
FIGURE 1 EXAMPLE OF SDI, MyGDI
2.3 The Importance of Standardization
Standards are key building blocks that will determine the success of an MyGDI. It emerges as the prime mover to allow data sharing and further integration, and promote economic management of resources by federal, state and local authorities. The goal of standardization in the field of GIS is to develop a set of standard that will support the understanding and usage of geographic information. Standards such as features attribute codes were used in order to provide multi-disciplinary GIS data sets that can be understood throughout all government agencies. Standards were normally divided into categories, such as Aeronautical, Built Environment, Demarcation, Geology, Hydrography. Then, this categories will be divided into more detailed sub-categories. Standardization also aims to provide the availability, access, integration and sharing of geographic information, thus enabling interoperability of geospatially enabled computer systems. For geospatial discovery, MyGDI adhere the concept of Clearinghouse which will be discuss later in this paper, to provide catalogue service that is normally use in a library information system. Further integration of this service with web mapping, live access to spatial data, and additional services can lead to an exciting user environments in which data can be discovered, evaluated, fused, and used in problem-solving. To achieve this, there is a real need to document the data infrastructure properly. A standard metadata that describes the content, quality, condition, and other characteristics of data was be used as a basis for data structures in MyGDI. A proper monitoring mechanism of the published metadata used in MyGDI to make sure that the metadata status is good in terms of completeness and the state of compliance to the metadata standards for business usage. Taking spatial data as an asset, the use of metadata can provide the following benefit :-
2.4 The Clearinghouse Concept
- Metadata helps organise and maintain an organisation's investment in data and provides information about an organisation's data holdings in catalogue form
- Coordinated metadata development avoids duplication of effort by ensuring the
organisation is aware of the existence of data sets
- Users can locate all available geospatial and associated data relevant to an area of interest
- Collection of metadata builds upon and enhances the data management procedures of the geospatial community
- Reporting of descriptive metadata promotes the availability of geospatial data beyond the traditional geospatial community
- Data providers are able to advertise and promote the availability of their data and
potentially link to on line services (e.g. text reports, images, web mapping and e-commerce) that relate to their specific data sets
Clearinghouse is a system of institution comprises of distributed network between the producers, managers and users of land information connected electronically, utilizing sophisticated software to facilitate the discovery of geospatial data, evaluation and on-line access. It is the backbone of NSDI for the management and production of spatial data in the electronic media. Clearinghouse serves the purpose of providing facility to all related agencies to standardize the production of spatial data which can be accessed online through Internet. Here might be a lot of different terms depending on the implementation of SDI, such as "Catalogue Services" (OpenGIS Consortium), "Spatial Data Directory" (Australian Spatial data Infrastructure) and the “Geospatial One-Stop Portal” (U.S. FGDC) but it all serves the same functionality . As it is distributed, the Catalogue Gateway and its user interface allows a user to query distributed collections of geospatial information through their metadata descriptions. This geospatial information may take the form of data or of services available to interact with geospatial data, described with complementary forms of metadata. Figure 3 shows the basic interactions of various individuals or organizations involved in the advertising and discovery of spatial data. A user interested in locating geospatial information uses a search user interface, fills out a search form, specifying queries for data with certain properties. The search request is passed to the Catalogue Gateway and poses the query of one or more registered catalogue servers. Each catalogue server manages a collection of metadata entries. Within the metadata entries there are instructions on how to access the spatial data being described.
FIGURE 2 BASIC INTERACTIONS IN SDI
Conventional software methodologies often fail to address the GIS-based application needs due to the complex and dynamic nature of the project. Software development is one of the most time consuming and expensive elements of implementing GIS. It also requires developer to integrate a lot of different technologies into one, high level user interactions with the system, multi step processing and analysis function. A highly Rapid Application Development methodology should be used in order to overcome this problem, as it allows high flexibility and continuous refinement and enhancement to the design during the software development process . At a high level it is an application development technique that uses prototypes, iterative customisation, and Computer Aided Software Engineering (CASE) Tools. The core element of RAD can be described as the following :-
- Prototyping:- One of the key aspects of RAD. Provide a platform to jumpstart design and flushing out user requirements. The initial prototype serves as a proof of concept to the client, but more importantly serves as a talking point and tool for refining requirements. Requirements normally may change during system development and RAD provide a flexible approach to suite the new requirements with the existing prototype. CASE tools were used in capturing requirements, designing data models and database for the prototype.
- Iterative Development:-Increasingly creating functional version of a system in a short amount of time.The Joint Application Development (JAD) that consists of users and developers will work together to produce requirements that feed the next version. Each development cycle provides the user an opportunity to provide feedback, requirements and view progress.
- Time Boxing:- Time boxing is the process of putting off features to future application versions in order to complete the current version in as short amount of time as possible. Strict time boxing is an important aspect of RAD, because without it scope creep can threaten to lengthen development iterations, thus limiting client feedback, minimizing the benefits of iterative development, and potentially reverting the process back to a waterfall methodology approach.
- Tools:- RAD is designed to take full advantage of the latest technology available to speed development. There are a lot of RAD tools in the market that were designed to fit certain RAD process. CASE tools, which normally fits in RAD development can be grouped into several categories:-
- Requirement gathering
- Data modeling
- Code Generation
Benefit of RAD for this project can be seen as:-
- Increasing speed of development, through different kinds of CASE tools implementation throughout the development process.
- Increasing software quality as developers may focus on particular modules on the prototype until it is totally finalized. Integration between modules and subsystem can be done later when all modules function properly as the client requested.
- Smooth system integration, while saving cost on testing with the use of Software Development Kit (SDK) and emulator programs.
- Encourage developer to work in a small team and divisions