GI Sdevelopment.net ---> Application ---> Agriculture Preparation of Saffron Cultivation Suitability Map Based on the Comparison of Different Weighting Methods in GIS Environment Manuchehr Farajzadeh Reza Mirza Bayati Mohammad Rahimi Tarbiat Modares University, Department of remote sensing and GIS, Tehran, Iran P.O.Box 14155-4838 Reza Amiri Pyam Nour Universuty Hashtrod, Iran farajzam@modares.ac.ir adabgeo@gmail.com mrahimi@irimet.net amiri.reza@gmail.com Abstract Saffron is the most expensive agricultural and medical crops in the world which have an important role in the economic development regions. Site selection for the cultivation of various agricultural crops in regard to environmental conditions of different geographic regions is an important aspect of agricultural studies and abilities of GIS systems. Different weighting methods in multi-criteria analysis were used in GIS to determine the best environment for various agricultural crops. The main object of this paper is to compare the four weighting methods including the boolean, ranking, rating and pair-wise comparison and introduce the best model in GIS environment. To do that, in the first step determined the necessary maps according to required environmental conditions including elevation, slope, land use, soil depth, availability of surface water, groundwater and temperature threshold maps were prepared in the GIS. Provided data layers were analysed using GIS multi-criteria evaluation analysis performed by boolean, ranking, rating and pairwise comparison methods and the related maps were produced for each of the applied methods in GIS and the results were compared. The result of this study indicates that the pairwise comparison method shows a better result than the other and presents GIS potential ability to select suitable lands for saffron cultivation. Key words: saffron cultivation, multicriteria analysis, climate, GIS, Nishabour plain. 1. Introduction The problem of selecting the correct land for the cultivation of a certain agriculture crops is a long-standing and mainly empirical issue (Kalogirou, 2002). Therefore many researchers have tried to prepare a standard framework for suitable and optimum agriculture land use. FAO presented a procedure to evaluation of lands potential in the cultivation of crops based on soil and environmental characteristics into five classes including highly suitable, moderately suitable, marginally suitable, currently not suitable and permanently not suitable (FAO, 1976, 1984, 1985). Considering the ability of GIS in the integration and analysis of spatial and non-spatial data, it is a very useful tool for the selection of suitable areas in the cultivation of specific crops into to different environmental conditions. So, recognition and identification of the sites which include required parameters such as topography, soil, climate, water resources and other parameters can be attained using the capabilities of GIS. The recognized zones by this approach are called Agro-climatic Zones (ACZ). Malczewski classified GIS-based land use suitability analysis into 3 main groups: 1)computer-assisted overlay mapping, 2)multicriteria decision making methods including multi-objective methods and multi-attribute methods and 3)artificial intelligence methods including fuzzy logic techniques, neural networks, evolutionary (genetic) algorithms and cellular automata (Malczewski, 2004). Using multi-criteria methods, Ceballos-Silva and Lopez-Blanco delineated suitable areas for the production of maize and potato crops in central Mexico (Ceballos- Silva and Lopez-Blanco, 2003). They used 3 main climate, soil and elevation data and have weighted these data using AHP procedure. The use of fuzzy method also has absorbed attentions of some researchers, for example Nisar et al. (2000) presented a GIS-based fuzzy membership model for crop-land suitability analysis. Liu and Samal (2002) used a fuzzy clustering approach to delineate agroecozones. Malczewski (2006) presented ordered weighted averaging with fuzzy quantifiers. Additionally, Zewen et al. (2003) using remote sensing data and GIS techniques made a possibility study for flax cultivation in some regions of Henan province of China. Caldiz et al. (2001) made an ecological agricultural classification and studied capabilities of agricultural lands in cultivation of potato by using GIS in Argentina. Preparation of Saffron Cultivation Suitability Map Based on the Compar... http://www.gisdevelopment.net/application/agriculture/cropping/ma07... 1 of 8 14/02/2011 7:17 PM