7 The concept of sustainable agriculture or farming SA SF involves
producing quality products in an environmentally benign, socially acceptable and economically efficient way Addeo et al. 2001, i.e. optimum utilization of the
available natural resource for efficient agricultural production. In order to comply these principles of SA one has to grow the crops where they suit best and for
which first and the foremost requirement is to carry out land suitability analysis Nisar Ahamed et al. 2000. So, land suitability analysis has to be carried out in
order to keep the sustainable agriculture.
2.3. Land Suitability Analysis
As stated above, land suitability is the ability of a given type of land to support a defined use. The process of land suitability classification is the
evaluation and grouping of specific areas of land in terms of their suitability for a defined use. The main objective of the land evaluation is the prediction of the
inherent capacity of a land unit to support a specific land use for a long period of time without deterioration, in order to minimize the socio-economic and
environmental costs. Land suitability analysis is an interdisciplinary approach by including the information from different domains like soil science, crop science,
meteorology, social science, economics and management.
2.4. Geographical Information Systems GIS
One of common geographical information system definition is a computer base softwaretool for collecting, storing, retrieving, transforming and displaying
spatial data from the real world ETSU, 1999. Traditionally, GIS have grown
8 from several diverse backgrounds such as computer-based mapping, database,
remote sensing, and design packages. As a result of this diverse background, GIS have the ability to answer a number of spatial questions that are not possible or
very time consuming, using traditional methods. A geographic information system is a power tool for handling spatial data
Aronoff, 1991. Large quantities data of data can also maintained and retrieve at greater speeds and lower cost per unit when computer-based systems are used.
The ability to manipulate the spatial data and corresponding attribute information and to integrate different types of data in single analysis and at high speed is
unmatched by any manual method. The ability to perform complex spatial analyses rapidly provides quantitative as well as qualitative advantages. Planning
scenarios, decision models, change detection and analysis, and other type of plans can be developed by making refinements to successive analyses.
Geographic data are now identified clearly as that required for geographic information systems. Many researchers claim that between 75 and 90 of
information used every day by most organizations are geographically based. For planner and decision makers, geographic information is especially important. The
geographic information system GIS is one of the most powerful tools in planning and decision making today Juppenlazt and Tian, 1996.
A geographical information system has four functional components Marble Amundson, 1988:
- A data input subsystem: collect andor processes spatial data derived from sources, such as existing maps, remote sensed data and direct
digital input.
9 - A data storage and retrieval subsystem: organizes spatial data in a
topologically structured form, which permits it to be quickly retrieved on the basis of either spatial or non spatial queries for subsequent
manipulation, analysis or display - A data manipulation and analysis subsystem: performs a number of
tasks, such as changing the form of the data through user-defined aggregation rules, or producing estimates of parameters for transfer to
external analytical type model. - A data-reporting subsystem is capable of displaying all or selected
portions of the spatial database in terms of standard reports or in a variety of cartographic formats.
The data input component converts data from their existing form into one that can be used by a GIS.
Data to be entered in a GIS are of two types: spatial data and associated non-spatial attribute data. Spatial data represent the geographic location of
features. Points, lines, and areas are used to represent geographic features. The non-spatial attribute data provide descriptive information like the name of a street,
the salinity of a lake, or the composition of a forest stand. During data input the spatial and attribute data must be entered and correctly linked i.e. the attributes
must be logically attached to the features they describe. Suitable verification procedures are needed to check that data quality standards are met Aronoff,
1991.
10 As most geographic information systems in the developing countries are
regional and resource and environment based, they are especially useful for implementing the sustainable development strategy.
2.5. Remote Sensing
