This paper presents a classified desertification hazard map of Zayandeh Rood Basin (Z.R.B) in Iran. There are potential climatic factors, the geographical location and human activities for developing desertification. The present study is based on the preview models and main factors of desertification in the study area. The classification method is based on such main parameters as the characteristic of soil, management and climate. Each parameter includes a sub-indicator with a weighing of

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... n one and two based on the MEDALUS model. DEM, LANDSAT images (ETM+), statistical data and vector map are used as the dataset for classifying the desertification map. The sum of score parameters was estimated by using a weighted average. In this study, Arc GIS 9.3 was used to analyze the vector and raster layer maps as well as a recognition survey of the study area using satellite images. In Z.R.B, the most important factors of desertification hazard are the geographical location of the area, salinization area, elevation, slope, and human activities. Thanks to the classification hazard map, the highest class is located on salinization, low vegetation, high wind erosion, low slope and elevation. Low-class area of the hazard map belongs to the largest part of the basin. An important factor of desertification in the area can be the geographical location of the basin located near the desert area. Using the raster data and GIS software are beneficial for the classification hazard map, especially for large areas.