1- Introduction
One-sided, unbalanced and unplanned development of cities, population and activity in the area, has left a great deal of the country's capacity useless, and has imposed a lot of problems on planners at different levels (ahmadi et.al,1389: 94). In order to achieve sustainable development, describing and assessment of the state of the environment and resources is necessary before any planning (movahhed, 1385: 11). Tourism, especially ecotourism is also no exception. Ecological potential assessment of tourism areas to use have been identified as a tool to achieve sustainable development (jowzi et al. 1388:71). In order to achieve sustainable development, land planning is essential and the infrastructure of this planning is environmental assessment, ecological potential assessment, measurement and potential of land with clear and pre-planned criteria. In this regard, from the 1960s, the geographic information system was established with a tangible progress in the spatial planning of land use to accelerate the development of various methods for determination of land ability for different uses.
In this study we have tried to define ecotourism potential, using assessment of Environmental Ecological potential in Chaharmahal and Bakhtiari Province to provide a dynamic setting for the development of the region. Therefore, because of an abundance of natural attractions such as wetlands, lakes, waterfalls, springs, rivers, mountains and peaks, caves, plains and forests, as well as historical- cultural attractions, such as bridges, villages and castles, there is a great potential to attract many visitors. In this study,it is attempted that with the use of GIS and ecological potential assessment model for establishment of tourism in the region, the potential can be investigated. The necessity and importance of this research is the factthat despite the unique characteristics of the province, especially in terms of nature, which can play a more active role in the economic, social and cultural area, and despite these diverse and valuable attractions, unfortunately less attention has been paid to this attractions so with a good planning and suitable using of available resources, the region can be developed sustainably.
 
2- Material and Methods
In Makhdoom systemic approach, ecological tourism model is provided for intensive and extensive outing (firoozi et al, 1392: 159). At this stage, by using collected data in the phases of analysis and conclusions in the environmental units with ecological models built for the user, the most appropriate activities are selected. Based on the results of investigations in Iran and the countries that are ecologically similar to Iran, a set of ecological models have been produced inIran which can be compared and measure ecological information about the model and determine the type of actions which should be taken. The model was used to determine the usages of the ecological models of agriculture - pasture, forestry, rural-, urban-industrial development, ecotourism, intensive tourism and aquaculture (Makhdoom, 1385: 185-212). This study seeks to find areas suitable for ecotourism (suitable Class A, suitable Class B and inappropriate). Therefore, suitable areas for loading the proposed activities appropriate to the potential of the region's stability have been identified, taking into account variables such as slope, rock and soil, aspect, water, plants, climate and weather and also preparation of needed maps.
 
3-Result and Discussion
In order to determine the ecological potential for ecotourism development in Chaharmahal and Bakhtiari Province, according to the preference of parameters in terms of importance in Makhdoom model (makhdoom, 1380: 203), first, slope map was developed in 9 classes using digital elevation model map and using the capabilities of ArcGIS. In the next stage, soil and rock condition was evaluated and the map was prepared. After determining the soil groups in the province, suitable areas for ecotourism class A, with suitable soil which is placed in Inceptisoils category, was separated. Climate is another factor considered in the assessment of ecological potential. In this context, the average temperature in warm period in the provinceis calculated. Since proper temperature during warm period for extensive recreation class A is 21-25 degrees Celsius, this feature was introduced in the attribute table. The next parameter is the number of sunny days. For extensive recreation class A for spring and summer seasons, the number of sunny days have to be more than 15 days per month. The last parameter is water. For extensive recreation class A, water level must be 5-12 liters per person. Citing the fact that the province, in terms of water resources is rich and has good precipitation, water levels parameter in the province was considered desirable.
In the last stage, all obtained maps, are mutually overlaid and finally a map is obtained,in which all the necessary conditions for an extensive recreation class A are introduced and shows all the suitable areas for extensive tourism.
 
4-Conclusion
After overlaying Maps and finishing ecological potential assessment process, it was found that a rather wide region of the province is suitable for developing ecotourism. According to the calculations done, about 32.1961square kilometers of the province is found suitable for extensive recreation (class A), the city of LORDEGAN has the largest share of the relevant regions and the city of BOROUJEN has the lowest share, respectively.