Archives

by S. Antony Norbert, Senior Lecturer in Geography, University of Colombo

Geographical information system is a major development in Quantitative Geography. The development in GIS as in the other fields like remote sensing, automated cartography and computer graphics have attracted substantial interest in recent years.

The development in GIS proceeded on a smaller scale in Europe compared to North America. But major strides have been made in using and developing computer-assisted cartography by several countries, notably Sweden, Norway, Denmark, France, The Netherlands, The United Kingdom and West Germany.

During the 1960s and the 1970s, there were two main trends in the application of computer method to mapping: (i) notably in the automation of existing tasks with an accent on cartographic accuracy and visual quality and (ii) on spatial analysis if we look into the history of using computers for mapping, thematic cartography, civil engineering, geography, mathematical studies of spatial variation, soil science, surveying and photogrammetry, rural and urban planning, utility networks and, remote sensing and image analysis. All these disciplines are attempting to develop a powerful set of tools for collecting, sorting, retrieving, transforming and displaying spatial data from the real world for a particular set of purpose. This contributes a "Geographic Information System" or in short GIS.

In the beginning, most GIS were set-up for local applications as well as for limited project area. Now many users particularly major government agencies reveal strong indications to set-up comprehensive countrywide system. For instance, the U.S. Geological Survey is envisioning a cartographic database containing all information, covering the entire United States.

The problems of establishing a GIS were considered recently by an internal Committee Organized by UNESCO and recommended a series of guidelines mostly in organizational and managerial aspects of GIS.

Although GIS has recently become more widely accepted as a generic term for the technology, the term geographic Information System was first published in a university discussion paper by Michael Dacey and Duane Marble (1965). Throughout this book, the term Geographic Information Management technology is used broadly and generically to include many specific types of computer systems used for mapping and processing of spatial information.

Burrough (1986) provides a more comprehensive definition of GIS: According to him it is "a set of tools for collecting, storing, retrieving at will, transforming, and displaying spatial data from the real world for a particular set of purposes".

Department of Environment (1987) defined it "a system for capturing, storing, checking, integrating, manipulating, analyzing, and displaying data which are spatially referenced to the Earth". According to Federal Inter-agency Coordinating Committee (1988), GIS is "a system of computer hardware, software, and procedures designed to support the capture, management, manipulation, analysis, modularly and display of spatially referenced data for solving complex planning and management problems".

Phil Parent (1988) said that GIS is a "System that contains spatially referenced data that can be analysed and converted to information for a specific set of purposes, or application... The key feature of a GIS is the analysis of data to provide new information. Rhind (1989) proposes that GIS is "a computer system that can hold and use data describing places on the Earth's surface.

In general, the definitions of GIS cover three main components. They reveal that GIS is a computer system. GIS also uses spatially referenced or geographical data and that GIS carries out various management and analysis tasks on these data including their input and output. Some authors consider that these are important elements of a GIS in addition to those that common to the definition above.

Others such as Maguire (1989) stress that data are the most important part of GIS. In practice, none of the main elements will function as a GIS isolation, so all might be considered of equal importance. However, it is perhaps the nature of the data used, and the attention given to the processing and interpretation of these data, that should lie at the center of any definition of GIS.

There have been so many attempts to define GIS that it has become difficult to select a definitive definition. Maguire (1991) offers a list of 11 different definitions. Pickles (1995) suggests that any definition of GIS will depend on who is giving it, and their background and viewpoint.

Pickles also considered that definitions of GIS are likely to change quickly as technology and applications develop further.

According to the International GIS Dictionary (1995), GIS is a "computer system for capturing, managing, integrating, manipulating, analyzing and displaying data which is spatially referenced to the Earth." Many people think of GIS as a computer tool for making maps. Actually, it is a complex technology beginning with the digital representation of landscapes (site, region and planet) captured by cameras, digitizers, or scanners, in some cases transmitted by satellites; and structured to support analysis.

Under this broad definition, GIS may include process models, as well as mapping and other spatial functions. GIS has the ability to integrate and analzse spatial data apart from the multitude of graphics, computer-aided design (CAD) and drafting, and mapping software systems.

A Geographic Information System (GIS) is a computer assemblage that has the capability to create a comprehensive database with many layers of information.

The assemblage provides visualization of spatial patterns by cross-referencing different layers of information. Geographic Information Systems provide superior tools for planning economic growth and development, disaster preparedness, natural resource management, and much more. Many academic institutions, government agencies, and consulting firms are now beginning to appreciate the benefits that can be gained from the interpolation of spatial and temporal data in one unique system

Components of GIS

Geographical data describe objects of the real world in terms of their position (coordinate system), attributes and spatial inter-relations with each other. These data can be accessed, transformed and manipulated interactively in GIS.

In the real sense, the data are coded on the surface of a piece of paper on magnetic tape, representing a model of the real world. Source of geographic data for computer manipulation includes digitized maps, field survey data, and aerial photographs and satellite imagery. Most image data are collected using remote sensing techniques.

Geographic Information Systems have three important components, which are (i) Computer hardware, (ii) Software modules, and (iii), a proper organizational context.

A digitizer or other device is used to convert data from maps and documents into digital form and send them to computer.

The Central Processing Unit (CPU) is linked to a disk drive storage unit, which provided space for storing data and programs. A plotter or other kind of display device is used to present the results of the data processing.

The tape drive is used for sorting data or programs on magnetic tape with other systems.

The user through the Visual Display Unit (VDU) known as the terminal controls the computer and its peripherals (Plotters, printers, digitizers, etc.,).

The software package for a geographical information system consists of five basic technical modules namely: (i) data input and verification (ii) data storage and data base management, (iii) data output and presentation, (iv) data transformation and (v) interaction with the user. Data input covers all aspects of transforming data, captured in the form existing maps, field observations and sensors (including aerial photography, satellites and recording instruments) into a compatible digital form.

Advantages of GIS

Digitized geographical information system is different from paper maps, which commonly show latitudes and longitudes, political boundaries and altitudes.

But GIS can integrate many kinds of information and derive numerical values from them and can be housed on computer.

Collecting worldwide district-level information and locating all the districts for a digitized GIS is a formidable task. But once accomplished it can be easily compared mathematically on any desired level. It can be displayed in a variety of map projections at various scales and degree of resolution. They can integrate or overlay much kind of data on a common geographical framework.

GIS as an analytical tool, allows resource managers to pinpoint specific areas, requiring priority action, for example, an index of desertification hazards has been developed with the help of remote sensing data, GIS and a global model to locate desertification areas. From these, the final map of desertification hazards was prepared by the FAO/UNEP at 1:25 million scale using seven sub-indexes of soil constraints, water, wind, salinization hazards, livestock carrying capacity, livestock pressure and population pressure.

The suspicions of an ovently theoretical approach to modelling in earlier years is overcome by the result of GIS; more over, the discipline has achieved high regard in this field. There has been a re-orientation of postgraduate studies in some foreign universities to provide much greater technical proficiency and also in staff appointments.

GIS is also being attempted in India, indeed, some specific GIS are on the anvil. Systems Institute at Pune in fact a pioneer in developing a GIS and this is now being taught to trainees in various disciplines.

There are some individuals who are also working on such a system, notably in Bangalore (WIPRO Computer Systems Personnel) and Hydrabad (Survey of India Personnel). In the light of these developments, unfortunately, there is an absence of good training programs for mathematically oriented geography to develop the high levels of skills required.

GIS accommodates a host of analytical procedures that facilitates resource appraisal and management. In earth science investigations, GIS demonstrates the integration of data elements to understand and analyze the complex nature of surface; sub surface and atmospheric problems and systems.

The manipulation of multiple geographic overlays can facilitate a clear understanding of the interaction of earth science elements and the spatial significance of their distribution. Recently, a series of papers have been edited on the application of GIS technology to land suitability studies, urban studies, water resource management, soil resource management, vegetation studies and global investigations.

The geographic information systems are ideal for such applications as land capability/suitability analysis, environment impact assessment, industrial site selection, transportation route location, open space planning, wildlife habitat analysis, mineral resources planning, forests land management and Coastal zone mapping. In recent years, with ever-increasing number of availability of computer resources, a geographic information system is quickly becoming a necessity in many applications.

People and GIS

Most definitions of GIS focus on the hardware, software, data and analysis components. It has been suggested that in certain business sectors, innovative flexible organizations with adequate resources and straightforward applications are more likely to succeed.

However, not all GISs are successful. There is evidence that many systems fail, and more are under-used.

GIS technology is now well established and has been in use since the 1960s.

The growth in application areas and products through the later years of the 20th century has helped GIS to become an accepted tool for the management and analysis of spatial data.

This trend is set to continue as computer technology continues to improve with faster and more powerful machines and as more data become available in digital formats directly compatible with GIS.

In addition, the striking advances in related technology such as surveying and field data collection, visualization and data base management technology are likely to influence this growth.

Sometimes difficulties in collecting data or other technical problems have set back system developments and applications however, there are also human and organizational problems at the root of GIS failures.

So it is important to have a good understanding of what a GIS can do and the data it is working with.

GIS and democracy

The establishment of a Geographic Information System database and the acquisition of hardware, software, and trained personnel are an expensive process.

These costs usually limit GIS technology to state agencies or large private corporations. With the continued diffusion of GIS into development planning, the issue of unequal access to data, technology and expertise is likely to reinforce the political and economic status quo and to work against more equitable planning decisions.

It is impossible to have sustainable and equitable development without free access to reliable and accurate information.

Without equitable access to GIS data and the technology, small users, local governments, non-profit community agencies, and non-mainstream groups are significantly disadvantaged in their capacity to engage in the decision making process.

The free flow of information is essential to truly democratic implementation of GIS.

Democratic principles are not confined to the area of politics only. Democracy also means the right of the people to seek and demand information from the agencies of government in order to understand, for example, their socio, economic and demographic conditions in which they are expected to play an important role in decision making. The "bottom up" approach to planning demands participation at grass roots level in the process of planning. Those who are at grass-roots levels should be furnished with geographic and other related information for their effective participation in the national development process.

Without an authentic database at micro level and macro level research is not possible, in the same token without research, development goals could not be achieved as planned.

Moreover in the present knowledge-based century or information-based century in which explosion of knowledge is witnessed it is becoming more and more important to facilitate the flow of information to reach even the lowest strata of the society.

This is very crucial in the context of the emergence of learning societies throughout the world irrespective of economic disparities among nations where all members of the society should enjoy their right to information.

Significantly, in multi-ethnic societies where ethnic, linguistics, or religious minorities make allegations of discrimination in respect of economic and educational opportunities, the flow of information to them without any obstacles is vital for them to formulate their own cases against such discriminatory practices. Hence, the need for proliferation and dissemination of information in a much more democratic manner.

Future of GIS

It is clear that even with the present shortcomings of GIS Technology, more and more people wish to have access to GIS. So we should be seriously looking for new ideas afforded by fractals, fuzzy logic and methods of artificial intelligence.

Since the imprecision of qualitative judgements are an integral part of human thought processes, we should be looking for better ways in which to describe the vagaries of the world.

For many organizations, the GIS appear as an exciting challenge, and this technology will quickly remove the many problems inherent in conventional methods of spatial data analysis. But new technology will certainly bring new problems with them.

In future, funding and continued financial supports will be the major determinants in determining the success or failure of the GIS.

STONE 'N' STRING

www.ppilk.com

News | Business | Features | Editorial | Security
Politics | World | Letters | Sports | Obituaries

Produced by Lake House
Copyright © 2003 The Associated Newspapers of Ceylon Ltd.
Comments and suggestions to :Web Manager