Application of What if? Planning Support System in Regional land Use planning to preserve Natural Ecosystem and Agriculture Lands

Land use planning is an important tool in adequate spatial distribution of land among various activities and functions at local, regional and national planning. Recent developments in information technology such as GIS and PPS (planning support system) has significantly improved the analytical abilities of land use planners in developing land use plan based on more accurate and detailed data as well as use of more sophisticated techniques. What if? Is a PPS developed especially for land use planning? What if? uses GIS technology and land use planning models to help planners create land suitability reports, land demand analysis, land allocation, and land use protection based on pre selected assumptions and scenarios.This study reports the applications and results of what if? In developing land use scenarios for Abadeh region in Fars Province of Iran as one of the first regional Application What If? Both in Iran and abroad. The results show that What If? Despite some software and conceptual limitations, can improve planner's ability in producing various land use scenarios according to different assumptions for large regions within an adequate time frame and using the existing digital data. 