one of the primitive prinicipals for agricultural planning is the determining of the agricultural units. These units are polygons that integrate ground and climatic factors. Each of these units has differents charateristics . in this study, Hamedan province, ground factors such as to pography , slope gradient, land types, soil deep and structure and climatic factors such as annual rainfall, annual temperature and evapotranspiration is considered. In first, using GIS function all of used data are weighted based on dry wheat potential . then all of data layers in GIS database is combibed into final layers using overlay function. The final map indicates the potential areas to dry wheat agriculture . to test of accurancy, the final map is compared with wheat productivity data in the study area. Result of this word indicates that the produced map has high accuracy and GIS is powerful techniques to producting of homogenous agroclimatic units.
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