kradfar@yahoo.com
www.kavehradfar.com
ABSTRACT
There's no doubt that data are vital to GIS operations, and the cost of managing multiple and various formats can be significant. Typically, geographic data is used by many people other than the producers. Data costs affect decisions at all levels to create frameworks to establish good communication channels for both users and producers of spatial data. Standards provide this common language, thus enabling parties to exchange data without misunderstandings (Fadaie et al. 2004). Although everybody recognise that standards have become essential in every corner of our life but they are usually considered as dull topics that seems to block inspiration and flexibility. A major challenge for the international community during the next decade is to make geographic information more accessible and useful to decision makers working on sustainable development problems. However, increasingly the major GIS vendors are seeing that their future lies in developing their products into ‘open systems’ environments (Armitage, 2006). This paper traces the emergence of standardisation, outlining the significance of National Spatial Data Infrastructure (NSDI) development to enterprise GIS. A key word in this approach is ‘interoperability’ which is applied at both the data and process levels.
Geoportal
Immediate access and use of geospatial information and applications are essential for effective management of all types of critical infrastructure systems such as: Geo-resource Management, Energy, Water Supply, Telecommunications, Transportation, Banking and Finance, Emergency Services, Health Services, and Government Services. The ability to rapidly share and apply geospatial information is important because emergency and disaster management in these domains requires cooperation among a broad range of organisations operating across many jurisdictions. Without a supporting, standards-based mechanism to search for, find, access and use this information, valuable sources may go unnoticed, data may be duplicated, and opportunities for collaboration may be lost.
The general purpose of metadata is to enable the user to identify, evaluate, select, obtain, and possibly use the needed datasets.
Data mining
Data mining or knowledge discovery in databases (KDD) is the nontrivial extraction of implicit, previously unknown, and potentially useful information from data. This encompasses a number of different technical approaches, such as clustering, data summarisation, classification rules and dependency networks. The patterns and regularities that are found by data analysing, represent valuable knowledge about the data sets and the objects in them.
Clearinghouses and Metadata
Metadata is commonly defined as "data about data" (ANZLIC 1996; Kildow 1996; ANZLIC 1997). Metadata allows a producer to describe a dataset fully so that users can understand the assumptions and limitations and evaluate the dataset's applicability for their intended use.
Geoportals contain metadata elements are designed to answer following questions (figure 1):
- Does a dataset on a specific topic exist (‘what’)?
- For a specific place (‘where’)?
- For a specific date or period (‘when’)?
- A point of contact to learn more about or order the dataset (‘who’)?
fig.1 European Geoportal
The United States Federal Geographic Data Committee (1994) defines The "National Geospatial Data Clearinghouse" as a distributed network of geospatial data producers, managers, and users linked electronically.
A clearinghouse is commonly an application that is located on a network that is used by people who have access to the network to obtain copies of datasets that the datasets custodian has made available on the network. Essentially a clearinghouse allows a user to search a network to find out what data are located on it, and then to actually gain access to that data, subject to the constraints placed on it by the data’s custodian.
Spatial Data Infrastructure
Data that are collected for a particular project are, in most cases, useful for other projects. Thus there is a need for this type of data to be placed in databases and made accessible for others to use. Different kinds of geoprocessing systems – Geographic Information Systems (GIS) and systems for remote sensing, photogrammetry, automated mapping, CADD, and navigation - have not mixed well. Still, it remains difficult for a researcher or practitioner to efficiently access, retrieve and apply data of interest without considerable effort to search map storages or visiting multiple web sites or, conduct many different queries, download files, reconcile different vendor formats and bring all the data into the same Spatial Reference System so that the information can be used. Diverse collections of data relevant to sustainable development are stored at the local, national and international levels in different vendor formats, and are available via multiple web sites and portals. This is important, not only to the organisations looking for the data, but also for the organisations with the data. Due to the "commoditisation" of data, organisations can use the SDIs to attempt to recoup some of the production costs of the dataset by selling/trading/sharing it with other organisations. They also help to minimise the duplication and fragmentation of fundamental datasets that have already been captured at great expense (Mooney et al. 1997). In many areas data of useable quality does not exist and that even where data does exist its usefulness may be reduced by access restrictions or by lack of standardisation with other data sets. Many if not most, SDI initiatives around the globe, at national and regional level, recognise the importance of fundamental data in the implementation of the infrastructure. When a SDI is being developed, one of the biggest issues that has to be addressed is what to do with all the legacy data (data that are already in existence). Data should be in a form that is easily transferred from one proprietary data format to another.
The second aspect of a SDI is to establish good communication channels between people/organisations concerned with spatial data (FGDC 1996).The third aspect of a SDI, which is brought about with the aid of good communication channels, is the introduction of common procedures and standards. By having standards for data storage etc. in SDIs, data can easily be shared amongst users and the best possible utilisation of the data can be achieved. Common standards within a SDI tend to solve many of the incompatibility problems for newly created data; however the legacy data will remain a problem.The goal is to create a framework of existing networks that leverage the important work that has already been accomplished by making it easier and quicker for a user to discover, combine and exploit existing data (Bacharach). Over time, many organisations and governments throughout the world have made major investments in collecting spatial data as a national resource that is fundamental to good decision-making. Managing this type of information, and maximising its use, has become a focus for both developed and undeveloped countries.
Canada has developed the Canadian Geospatial Data Infrastructure, with funding of C$60 million over five years. (Canadian Geospatial Data Infrastructure 2006)
This concept is established in Australia as ASDI to set up a distributed network of databases, managed by individual government and industry custodians (Australian Spatial Data Infrastructure 2006). The Permanent Committee on GIS Infrastructure for Asia and the Pacific (PCGIAP) has a vision for an Asia-Pacific Spatial Data Infrastructure (APSDI) that is a network of databases, located throughout the region to provide the fundamental data needed by the region.
In United States the Federal Geographic Data Committee (FGDC 1996) defined a SDI as an umbrella of policies, standards, and procedures and delineated these major initiatives to develop a National Spatial
Data Infrastructure (NSDI) which is accessible through the National Spatial Data Clearinghouse:
- Creation of a distributed electronic network of data producers and users, known as the National Geospatial Data Clearinghouse.
- Development of standards for data documentation, collection, and exchange.
- Formulation of procedures and partnerships to create a national digital geospatial data framework that would include important basic categories of data significant to a broad variety of users.
- Development of new relationships that allow organizations and individuals from all sectors to work together to share geospatial data.
The NSDI has come to be seen as the technology, policies, criteria, standards and people to assemble geographic data nationwide to serve a variety of users in public and private sector applications of geospatial data in such areas as transportation, community development, agriculture, emergency response, environmental management and information technology.
Ultimately this framework will illustrate the best practices promoted by the Global Spatial Data Infrastructure. The definition of the GSDI was adopted at the 2nd GSDI Conference in 1997.The purpose of the GSDI is to encourage the growth of compatible Spatial Data Infrastructures capable of supporting collaboration on regional and global issues of importance. In addition, it provides practical guidelines on how to establish spatial infrastructures. GSDI is also working closely with the United Nations Geographic Information Working Group (UNGIWG). This working group that was established for the needs of peacekeeping actions, sustainable development and the eradication of poverty, collaborate with ISO/TC 211 and use standards it has developed.
The potential realisation of a GSDI has captured the imagination and attention of policy-makers, administrators, industry, and the professions. Although not widely known in the general community or commonly understood by its proponents the GSDI is seen by many as a central element in the global response to the challenge of sustainable development (Holland 1999).
In 1992 the Japanese Ministry of Construction proposed Global Map product concept to deliver basic topographic and thematic data sets globally.
The Spatial Data Transfer Standard
The Spatial Data Transfer Standard (SDTS) is an intermediate transfer format for the transfer of spatial data. Figure 2 is a simple example of a spatial data transfer processors (SDTP) encoding spatial data from an Arc/Info format into an SDTS profile and then a separate SDTP decodes the spatial data in the profile into an INGRES format.
Fig.2. SDTS encoding and decoding
Digital geographic data is an attempt to model and describe the real world for use in computer analysis and graphic display of information. Any description of reality is always an abstraction. There is seldom perfect, complete, and correct data. To ensure that data is not misused, the assumptions and limitations affecting the creation of data must be fully documented. The objective of International Standard is to provide a structure for describing digital geographic data. Though this International Standard is applicable to digital data, its principles can be extended to many other forms of geographic data such as maps, charts, and textual documents as well as non-geographic data.
The geospatial standard defines the schema required for describing geographic information and services. It provides information about the identification, the extent, the quality, the spatial and temporal schema, spatial reference, and distribution of digital geographic data mandatory and conditional metadata sections, metadata entities, and metadata elements and a method for extending metadata to fit specialised needs.
By focusing on the adoption of standards-based geographic information and technology offerings now, sustainable development researchers and practitioners in the field and at the national and international support levels will be better able to share information, interconnect applications, and minimise system integration issues as the range of product offerings increases and as access to the internet expands. A standard is a code of practice for procedures to create, store transfer or use data. This is to ensure that when information is generated in one system its quality is still the same when used in another system. The success of different data formats has largely been governed by the size of the user community using that standard and the ease with which the standard can actually be implemented. For example, the standards devised by the FGDC have been adopted both within the USA and by a wider global audience. This global influence can at least in part be attributed to the impact of the large US GIS companies. GI standards can have three different implementations: a Generic view, a Profile view, or a Product view (Fadaie et al. 2004).These standards may specify, for geographic information, methods, tools and services for data management (including definition and description), acquiring, processing, analysing, accessing, presenting and transferring such data in digital / electronic form between different users, systems and locations. It is evident that the potential of geographic information can be achieved only with clear and well-defined data definitions (Stiggelbout, 1999).
There are two strands of thought present in the discussion of data standards. One is largely about the fact that many of the factors affecting data quality operate at the user end of the GIS system. Another strand of thought more closely associated with various national and international organizations to define specifications. Thus the quality can be best managed by standards to establish principles and ensure compatibility and users to implement them. Jingtong (2001) describes different points of view among experts and among organizations have to be hardly coordinated. If strategies were designed solely for and by specific users, then we would have, for instance, different data formats that would not help improve the implementation of quality controls. Compatibility and credibility require standards.
The main beneficiaries of data standards are users. They need standards to:
- Increase the availability of data
- Increase the suitability of data for additional purposes beyond that for which it was originally created
- Enable datasets to be integrated, creating new information
- Enable spatial analysis to be performed
- Improve understanding of data
- Reduce costs of creating and handling data
Generate new market opportunities (Armitage 2006).
Previously, standardisation was a process for recognising and codifying the status quo of technology. Standardisation is now beginning to define the requirements and implementation of new technology. Standards, such as Spatial Data Transfer Standard (SDTS) and DIGEST, are designed to be capable of representing virtually any data model in an attempt to capture all different perspectives of geographic information (Arctur et al, 1998).
Complexity, and diversity of geographic datasets grow, a method for providing an understanding of all aspects of this data grows in importance. The aim of interoperability is to develop a geospatial information community with one set of semantics, valid feature and attribute relationships, data capture standards, formalised symbology, data management procedures and ownership of individual feature collections (meta-data). Standards constitute an important approach to information exchange (Hadzilakosl et al, 2000). They provide a formalisation of spatial data concepts, data structures, and logical and physical formats that facilitates spatial data exchange between dissimilar computer systems (Bishr et al, 1998; Salge, 1998)
The work of preparing International Standards is normally carried out through ISO (the International Organization for Standardisation) technical committees. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. Three primary trends in standardisation were considered, CEN/TC 287, Open GIS and ISO/TC 211. The CEN/TC287 ceased its activities after preparing nearly 20 standards, to avoid duplicate work.
ISO/TC-211
The goal of ISO/TC 211 is to develop a family of international standards that will increase the availability, access, integration, and sharing of geographic information, enable inter-operability of geospatially enabled computer systems and ease the establishment of geospatial infrastructures on local, regional and global level and contribute to sustainable development.
Almost all the countries have adopted national standards for the preparation of their datasets. The regional fundamental technical questionnaire was sent to all 55 countries in the Asia-Pacific region through Working Group 2 (Rajabifard et al, 2000). Very few countries have commenced converting their datasets into the ISO/TC211 standards.
Armitage (2006) believes that good standards are simple and unique. Standards are fit in below items:
- Access, technology
- Content (data)
- Organization
- Education
International Organisations like ISO base their decisions on consensus and are fairly independent of the interest of individual governments or industries (Figure 3). The members of International Consortia are drawn primarily from industry, often from government agencies, and universities are occasionally represented.
ISO is the umbrella organization for any national standardisation activities. The national bodies are often unable to provide the complete range of expertise required for standard setting. Therefore scientist and engineers usually exchange their knowledge within dedicated international organisations. The idea for a new standard is always born outside ISO and ISO`s role is to formalise a method to forward the idea to an internationally approved standard.
Structure
ISO members are national members and liaison members. Normally national bodies are participate members (P-members) with full voting rights while others are observing members (O-members) with an observer (non-voting) status only.
30 Standards in the TC211 19100 Suite:
- ISO 19101 - Reference model
- ISO 19102 - Overview
- ISO 19103 - Conceptual schema language
- ISO 19104 - Terminology
- ISO 19105 - Conformance and testing
- ISO 19106 - Profiles
- ISO 19107 - Spatial schema
- ISO 19108 - Temporal schema
- ISO 19109 - Rules for application schema
- ISO 19110 - Feature cataloguing methodology
- ISO 19111 - Spatial referencing by coordinates
- ISO 19112 - Spatial referencing by geographic identifiers
- ISO 19113 - Quality principles
- ISO 19114 - Quality evaluation procedures
- ISO 19115 - Metadata
- ISO 19116 - Positioning services
- ISO 19117 - Portrayal
- ISO 19118 - Encoding
- ISO 19119 - Services
- ISO/TR 19120 - Functional standards + new revisions
- ISO/TR 19121 - Imagery and gridded data
- ISO/TR 19122 - Qualifications and certification of personnel
- ISO 19123 - Schema for coverage geometry and functions
- ISO 19124 - Imagery and gridded data components
- ISO 19125 - Common architecture- SQL option
- ISO 19126 - Profile - FACC Data Dictionary
- ISO 19127 - Geodetic codes and parameters
- ISO 19128 - Web Map Server Interface
- ISO 19129 - Imagery, gridded and coverage framework
- ISO 19130 - Sensor and data model for imagery and gridded data
- ISO 19133 - Location-based services -- Tracking and navigation
- ISO 19135 - Procedures for item registration
The Open GIS Consortium Inc. (OGC) was founded in 1994 in response to widespread recognition of incompatibilities in spatial data transfers and its many negative consequences for industry, government and academia. Geoprocessing software vendors, database software vendors, visualisation software vendors, system integrators, computer vendors, telecommunication companies, universities, information providers and US federal agencies have joined the consortium to participate in creating a software specification and new business strategies that will help to solve these problems and fulfill these potentials. The data may have been produced for different purposes and may in fact still reside under the primary control of the system used in its production.
The main difference that exists between SDTS and OGC is that SDTS is a transfer standard, whereas OGC is an operational standard. OGC on the other hand not only has the SDTS goal of easy data transfer, but also the goal of allowing a user on a local machine to use the geoprocessing capabilities of the remote server on the remote servers data, whilst viewing the results on their local computer.
Standardization of Geospatial Data in Iran
Awareness of the current situation is one of the important factors needed in pursuing any strategic plan for future National Spatial Data Infrastructure Development.
Surveying and Mapping Standards and Specifications Standards and specifications required for surveying and mapping are developed by the National Cartographic Center’s Standards Committee in the context of the Management and Planning Organization. User needs are gathered through communication with the National Council of GIS Users.
Cooperation with International Standardization Bodies
The Institute of Standards and Industrial Research of Iran (ISIRI) is the national standardization body. The National Cartographic Center (NCC) is the chair and secretariat for the ISIRI/TC211 Mirror Committee which is responsible for commenting and voting on ISO/TC211 drafts.
Iran is currently an O-Member (Observer) of the ISO/TC211 Technical Committee, but is in the capacity building phase in order to be able to elevate to P-membership in the future.
Promotion of the ISO19100 Standards in Iran
Realizing the importance of the ISO/TC211 activities (and the associated ISO19100 series of standards) concerning standardization of geospatial information, NCC has taken the initiative of promoting these standards in Iran. The process consists of translating the standards into Farsi, technical review, and adoption through the national standardization process. NCC’s Standards Committee, in coordination with ISIRI and other relevant organizations, is responsible for this activity. Currently six standards are in process.
NSDI
It is also worth noting that formal activities for development of a National Spatial Data Infrastructure (NSDI) for Iran have begun (which will also address the subject of standards as one of its components) (Ahmadyieh 2006 and Ghavamian 2006).
Conclusion
Geospatial information is needed by decision makers to be used in diverse disciplines. Searching through Geoportals, retrieving and adopting information is the most time consuming step to implement any GIS project. Many countries now are involved in the process of geospatial standardisation to reduce the cost and duplicated works and increase interoperability. ISO/TC211 has the main role to formalise methods and deploy it as international standards. Getting people to agree on acceptable international standards guarantees sustainable development in national and regional levels.
Reference
- Australian Spatial Data Infrastructure viewed September 12, 2006 http://www.anzlic.org.au/infrastructure_ASDI.html
- Canadian Geospatial Data Infrastructure viewed 5 August 2006 http://www.geoconnections.org/CGDI.cfm/fuseaction/aboutGcs.welcome/gcs.cfm
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