boolean logic

 The construction of underground dams is a method of controlling and storing water in wet periods for use in dry periods. Underground dams are structures for blocking water under the surface of the earth. Although the underground dam is considered a new method for water extraction, satisfactory results of their implementation have been reported in different parts of the world. This research was conducted with the aim of determining the appropriate site selection criteria for the construction of underground dams in Ben County, Chaharmahal and Bakhtiari province, Iran. The most important problem in the development and construction of underground dams is the complexity of determining suitable places for their establishment. Determining the most important criteria for identifying the suitable places, selecting the most suitable decision-making method in the integration of information layers, and ranking the vulnerable areas have greatly helped in the implementation of these structures.The investigated area includes Ben township with an area of 14327 hectares, which is located in the north to northwest of Chaharmahal and Bakhtiari province. Ben, Vardanjan, and Yancheshmeh cities are located in this area. The research employed Boolean logic, aerial photos, and Landsat satellite images to identify 10 suitable axes for dam construction. Also the study utilized the Analytic Hierarchy Process (AHP) to prioritize the axes based on hydrological, economic-social parameteres. After specifying the axes in the first stage and determining their criteria and value, using the MADM method and based on the AHP decision-making method, the suitable points for the construction of the underground dam were prioritized. According to the studied area conditions and the available information, 4 main criteria, 3 sub-criteria and 17 indicators were used in the process of AHP. In the following, using the relative values ​​determined by the binary comparison method for these indices and criteria, the appropriateness index was calculated for each axis.In the hierarchical analysis method, inappropriate areas were eliminated in the first step using Boolean logic, and three elimination criteria: slope, land use and geology. Then with the field survey in the determined areas and using the Boolean method, 10 suitable axes were selected for the construction of the underground dam. To establish the priorities MADM method was employed based on the decision-making flow, also the AHP method was applied and questionnaire was analyzed using the Delphi method, to consider expert opinions. According to the value of the main criteria and indicators, hydrological factors are given priority with a weight of 0.51, followed by economic-social factors with a weight of 0.30, reservoir with a weight of 0.13, and axis with a weight of 0.058. The study identified the quantity of water (runoff height) and the depth of alluvium as the most critical indicators, with weights of 0.833 and 0.743, respectively. Subsequently, axis 1 (identified as B) and axis 2 (identified as A) were determined as the first and second priorities for consideration by the implementation department. The results showed that the quantity of water is more important than the quality. That is because in the absence or lack of subsurface flows, the reservoir of the underground dam is not completely drained, leading to many problems, including difficulties in suppling the water needs of the residents. According to the results, the higher the water quality (water hardness) has the greater relative importance.  The downstream areas of pollution sources were considered as unsuitable places and removed. The results indicated that a larger reservoir volume will make it more suitable. The best places to construct an underground dam in a river are the gorges withthe highest reservoir level in the upstream areas. By the results of the reservoir depth factor, the best areas were the alluviums with a depth of less than 10 meters. The outcomes of the this investigation indicated that most of the waterways 3 and 4 were located on slopes of less than 5%, which were suitable areas for the construction of underground dams, because the slope factor has an inverse relationship with the volume of the reservoir and the amount of permeability. The depth and length of the dam axes are the most important economic factors in an underground dam, and due to the limitations in the axes drilling depth compared to the length of the axes, this criterion cocidered as the first priority. The suitable axes were those that, in addition to having a suitable reservoir for storing water upstream, had the minimum possible depth and length for the implementation of the wall. Shorter axes had more value and importance than other axes. Among the socio-economic sub-criteria, the factor affecting the water resources -especially the downstream qanats- was more important, because the change in the qanat water supply causes local challenges. The results revealed that the index of distance from the village was more important than the distance from the road. The existence of a road in the construction site of the underground dam increases the access and reduces the costs related to the construction and maintenance of the structure.

In arid and semi-arid regions where there is low rainfall with inappropriate distribution, one of the ways to use floods is to spread them in susceptible areas. The aim of this study is to find the best place for flood spreading using GIS and decision-making methods in Farimaneh watershed. For this purpose, the slope, topography (altitude levels), geology, land use type, soil permeability, geomorphology, geological formations, vegetation, and soil factors were used. For weighting the quantitative variables, fuzzy logic with trapezoidal and triangular membership function, and for qualitative variables, fuzzy logic with hierarchical analysis was used. Flood spreading prone areas were presented using GIS and the concepts of layer integration from fuzzy logic, Boolean logic, and overlay index methods. To determine and prioritize susceptible areas the Boolean operators AND OR, fuzzy AND OR, Fuzzy algebraic and sum-product, fuzzy gamma from 0.1 to 0.9, and multi-criteria evaluation was used. By comparing the obtained results with the observational data, it was concluded that the Fuzzy and, multi-criteria evaluation and fuzzy gamma 0.8 and 0.9 methods were most consistent with the observational data and among these methods, the multivariate evaluation method was found to be more appropriate. Also, among the parameters, slope, vegetation cover, and permeability had the highest weights.

Inadequate temporal and spatial distribution of precipitation in arid and semi-arid regions, cause destructive floods in addition to loss of surface runoff. Therefore, controlling surface runoff and its proper utilization through the construction of rainwater catchment systems can be a good way to prevent water loss. Traditional methods may be time wasting and concise. Geographic information systems provide new methods and models of using huge number of maps and data for analysis in a short time with best results and conciseness. This project was implemented in Kan Basin as a pilot which covers an area about 197 km2. Different maps including slope, land use, precipitation, vegetation cover, soil hydrologic groups and geology were overlayed. Land use maps were extracted from ETM+ 8 satellite images of 2014 along with field controls. Then layers were weighted according to their importance and role of each map. Suitable areas for establishing rainwater catchment systems in each model were determined by overlaying in the frameworks of different models including Boolean logic, Index overlay and Fuzzy logic and compared with control points which were implemented with Ministry of Jihad Agriculture. The results showed that the operators gamma=0.2, gamma=0.3 and Product from Fuzzy logic model had the most overlap with the control areas, the best integrated model for determining the appropriate locations for the construction of rainwater catchment systems in the study region.

Controlling and managing of seasonal and sudden floods in arid and semi-arid regions, especially in areas where surface water is out of reach is necessary. Flood spreading is one of the best ways to control surface runoff and recharge groundwater resources. In the present study, the appropriate sites for flood spreading project in border area of Taybad county in Khorasan Razavi province is selected using Boolean logic .For prioritization the suitable locations, TOPSIS and VIKOR multi-criteria decision making methods were used. Firstly, using Boolean logic inappropriate areas based were removed on criteria (slopes greater than 8%, urban area, agriculture and covered pediment). Then, 11 zones were selected as the suitable areas of using TOPSIS and VIKOR models based on the criteria  of slope, groundwater quality, geology, alluvium thickness, transmission capability, drainage density, surface permeability, groundwater loss, distance from the village, distance from wells and land use.. Results showed that most suitable areas are located in alluvial fans. Based on the TOPSIS model, location J with value of 0.75 was selected as the best site, and using the VIKOR model, location K with a value of 0.96 was selected as the best location for flood spreading projects.

Most part of Iran including Chaharmahal and Bakhtiari province is arid and semi-arid; thus in most parts of the region, groundwater is the only source of water. Thus, in the most parts of the region, groundwater is the only water resource, and is a major constraint on economic and social development. In arid regions, the underground dam is a new industrial site for supplying water for farming, especially in summer. An underground dam is a sub-surface barrier across the stream which retards the natural ground water flow of the system and stores water below ground surface to meet the demands during the period of need. The aim of this study was to prioritize the effective factors in the construction of underground dams and to develop and evaluate a multi-criteria decision making system based on GIS techniques in order to identify and prioritize potential areas for building underground dams in the watershed of Shahrekord. Marghmalek-Shahrekord watershed is located in north east of Chaharmahal and Bakhtiari province. This watershed is located in Sanandaj-Sirjan zone based on structural divisions and the atmospheric rainfall in the basin is mainly influenced by low-pressure Mediterranean systems. In order to accelerate the decision-making process, as well as avoiding the accumulation of excessive information for a surveyed problem, it is first necessary to eliminate inappropriate points by considering a number of key criteria and factors. At the first, suitable areas for establishing underground dams were determined with ommisive criteria and using Boolean logic and suitable areas for establishing underground dams were determined. The axes that do not cut the Qanat's gallery and are suitable from the aspect of length and area of the reservoir were identified. In the next stage, the proposed locations were prioritized using the analytic hierarchy process. Therefore, the indices that are more fit, matches the more suitable axes for the construction of underground dams in the study area. Five scenarios were considered for the prioritization. Quaternary formations are suitable for the construction of underground dam. Poor, medium and good rangelands and garden lands are suitable for underground dam. According to the first, second, third and fourth scenarios, axis number 46 and according to the five scenarios, axis number 41 have the first priority for groundwater dam construction. The results showed that the hydrologic factors and the socioeconomic factors were chosen as the most important factors with weights of 0.51 and 0.30, respectively. In determining the value of the indicators, the water quantity (runoff height) with a weight of 0.833 and also the depth of alluvium with a weight of 0.743 are more important than other indicators that this indicates the importance of the hydrologic criterion for experts. The best axes for the construction of an underground dam are in the alluvial river bed with high subsurface flow, the large reservoir capacity, high runoff volume and areas with high permeability and low slope. By integrating the maps of the Qanats axis of the study area and the map of possible gaps of underground dam construction, 15 axes were identified for the construction of underground dam in Marghmalek-Shahrekord watershed. The results of the reservoir analysis indicated that suitable subsurface reservoirs in these areas are matched with this fact that with decreasing slope, the length of the reservoir increase, that ultimately causes increases the volume of the reservoir. The large area of the watershed upstream of the dam has a higher priority and value because the high amount of runoff passes through the construction site. The depth of the alluvium has the most relative importance among the axis indices, because in the economy of an underground dam, length and depth of axis are most important. By investigating the results of the reservoir depth, it was found that the best region are alluvial bed with a depth of less than 10 meters, that is consistent with the results of Chezgi (2015). The water of these tables is very good in terms of quality because they are naturally refined by constituent lands. Also, they have a high subsurface discharge. These valleys are the best and most suitable place for underground water extraction. According to the obtained results about the slope, the relative importance of the slope increases with its lowering. The results of this study showed that most of waterways 3 and 4 were located at slopes less than 5 percent, which are suitable areas for building underground dam because the gradient factor has inverse relationship with reservoir volume and permeability and is consistent with results of Nilsson (1988); Rezaei et al. (2013) and Chezgi (2015). The proposed method can accurately be used to select the suitable sites for construction of underground dams through detailed and accurate surveys and by considering the effective factors.

The spatial and temporal distribution of precipitation result in surface runoff and flood. Using this water in artificial recharge is a solution to increase groundwater recharge. Because the groundwater is considered as the major source of 99% of all retrievable fresh water, optimization of its usage would be very crucial. Groundwater artificial recharge using surface water is the recommended solution because that increases the aquifer storage. To identify the suitable sites for groundwater artificial recharge in the aquifer of Hamedan- Bahar plain, the six effective parameters including the ground slope, surface infiltration rate, vadoze zone thickness, electrical conductivity of the groundwater, land-use, were used. In the first method, each maps were classified based on the Boolean logic and then integrated via the AND operator. The results showed that 26% of study area was suitable for ground water recharge. Then, suitable areas were divided to three subsets using overlay method. The 0.53% was suitable, 21% was moderate and no area with very suitable appropriateness. In the third method, layers were rated based on the Fuzzy logic and integrated with the Fuzzy algebraic product operator. The 2.25, 7.71 and 16.76% of the study area were identified very suitable, suitable and assigned moderate, respectively. The result of Boolean logic sensitivity analysis showed that suitable zones increase 1.5% while suitable ranges in all parameters increase 50% against 0.5% reduction of suitable points at 50% reduction of suitable ranges of all parameters.

In order to create sustainable development in the tourism industry, the proper understanding of environmental potentials and its sensitivity to human activities is very important. This study has identified and prioritized the potential of ecotourism sites in the Kojur basin of Mazandaran province. Physiographies criteria, including slope, direction, and elevation, as well as criteria of distance from road, river, village, sliding locations and canopy percent, were selected as the appropriate index. The criteria were evaluated and fuzzy by the experts and Analytic hierarchy process (AHP) method. Subsequently, using the Ordered weighted average (OWA) scenarios, the appropriate ecotourism site was selected. To reduce risk and increase managerial power, Boolean logic was used. The results showed that the landslide and the roads had a maximum value of 0.315 and 0.238, respectively. The output maps of the OWA scenarios have shown that the northeastern range of the cougar basin is the most optimal location for the establishment of the ecotourism site, and the northern region was ranked next. In the scenario of the low-risk level and non-compensated, and low-risk level and low compensation scenario, 83 hectares of land were recognized for the appropriate ecotourism site. While, average risk and complete compensation, high risk and low compensation, average risk and non-compensation and high risk and no compensation, were 3179, 1255, 1909, and 2577 hectares respectively for ecotourism sites. The Boolean logic output showed that about 47 hectares of northeastern lands of Kojour basin are an appropriate ecotourism site.

Iran and accordingly the study area due to placing on the dry belt region of the world are always faced with the drought phenomenon and shortage of rainfall. Accordingly, the efficient use of water and the management of these areas are integral component requirements of such areas. Precipitation pattern in arid areas occurs as storms with the high intensity usually in short time and causing huge runoff in the basin that will carry valuable surface soil and decreasing water infiltration opportunity in the soil. Different techniques of rainwater harvesting from natural lands, improved micro-catchments or agricultural micro-basins will lead to developing sustainable economical agriculture and store runoff into soils, dams, terraces, ponds, ditches, and reservoirs. The study area with 470 mm rainfall and runoff coefficient of 0.26 has the high potential of water harvesting at the basin scale. Previous studies show that lower gammas fuzzy logic values target macro-catchment systems of water harvesting well, but in micro-catchment systems with using fuzzy operators are less researched.
In this research for finding suitable areas for water harvesting, 3 systems including semi-circular bunds, contour furrow, and bench terrace with using GIS in Nazlu basin with 1507 km2 area, of west Azarbijan were investigated. Watershed factors such as climate, physiographic and hydrological factors, six important layers of precipitation, slope, land use, hydrologic soil groups, and drainage and soil depth were selected. For intersecting and making layers dimensionless, Fuzzy logic with trapezoidal membership function and Fuzzy logic with the analytical hierarchical process (AHP) were used for the quantitative and qualitative variables respectively. AND for combining of layers Boolean AND, Boolean OR, Fuzzy algebraic Product, Fuzzy algebraic sum, Fuzzy gamma of 0.1 to 0.9 methods were examined.
The “measure of similarity” is used for comparisons of filed observed and combination outputs. The results show for the crescent bankette and the Gamma-0.9 Fuzzy, this figure equals 0.824 and for counter furrow, equals 0.906. These figures indicate that fuzzy gamma 0.9 has better suitability than other method and also Boolean logic model do not show suitable results. Similarity index in fuzzy logic increases up to 0.9 gamma and returns below 0.9. High Gamma for site selection of Micro-catchment water harvesting systems shows better results. The 30% of the basin is suitable for semi-circular bunds, the 11.5% for contour furrow and 6.3% for bench terrace.
The results show that for determining the locations suitable to micro-catchment water harvesting methods, Boolean methods are less useful due to low precision and the usage of newer methods of gamma fuzzy logic should be considered, instead.

Flood control and storage are the main factors in combating desertification especially in arid and semi arid regions. This study aims at recognizing suitable sites for flood spreading by coupling fuzzy inference systems and RS & GIS techniques. In this resarch, Davarzan watershed selected as a one of the most flood prone area in northeastern Iran because of its strategic location in upstream of Etka agricultural regions. Various thematic maps of the study area including slope map, surface infiltration, pollution generating potential of each formation type, runoff volume and aquifer depth on 1:50000 scales were selected as inputs and analyzed using ARC GIS 9.3 package. Land use map on 2002s ETM image after field measurement and identifying training sites in ENVI 4.8 software is also extracted. For weighting and integration of information layers, any techniques such as index overlay, Boolean logic and fuzzy logic model has been used. Results showed that fuzzy gamma 0.9 and index overlay with maximum overlaying surface with the control sites (5 and 4% respectively) are the most appropriate methods. Screening output maps, it is revealed that alluvial fan located in upstream of Etka agricultural regions was unsuitable. It is mainly due to accelerated erodibility of formations PLc and K1l, lying on the outlet section and resulted in aggregated marl sediments on the alluvial fan which made it unsuitable for flood spreading.

Artificial recharge of aquifers using flood spreading method is a way to increase the groundwater volume and decrease the trend of water table depletion. The most important step in the implementation of flood spreading is the identification of suitable zones. Hence, geographic information system (GIS) and integration methods consist of Boolean logic, fuzzy logic, and overlay index were used to identify the most suitable zones for flood spreading with the aim of artificial recharge of the Sarkhoon plain of Bandar - Abbas. Firstly, five effective factors including surface permeability, slope, alluvium thickness, the ability to water convey in the alluvium and the salinity of water were prepared in ArcGIS software environment. Then, the weights of the layers were determined using the mentioned methods. The comparison of the weighting methods was accomplished using the Kappa statistic, based on the comparison of projected layers with ground control points. According to results, Boolean logic, overlay index, and fuzzy logic respectively projected 34.4%, 35.8%, and 71.4% of the study area as suitable for flood spreading without the constraint of land us. By the use of land use constraint these areas decrease to 21.9%, 26.7%, and 45.66%, respectively. Totally, fuzzy logic with the highest similarity and the highest Kappa statistic was identified as the best method.

One of the water management methods that had wide application in recent years is the artificial recharge. The aim of this study is to determine the suitable sites for artificial recharge in Oshtorinan plain located in Boroujerd City. The effective factors of artificial recharge were identified includes: geology, slope, the thickness of the unsaturated zones, groundwater quality, aquifer transmissivity, hydraulic gradient, storage coefficient, distance from surface water sources, and land use. In first, raster maps for different layers were prepared and arranged using the paired comparison method and Analytic Hierarchy Process (AHP). Raster layers were integrated using the Weighted Index Overlay Method. Unsuitable areas according to the proximity to wells, springs and Qantas were eliminated by using the Boolean model, and the artificial recharge map was prepared. Three sites were determined for artificial recharge in Oshtorinan Plain. The potential artificial recharge map shown, 17% of the region area had quite suitable, 21% was suitable, 31% was moderately suitable, 18% was unsuitable and 13% was prefect unsuitable for artificial recharge. Finally, through field visiting four sites were determined for artificial recharge in Oshtorinan Plain.

Productivity of the floods in the country which suffering from a severe shortage of water resources, is inevitable and flood spreading in areas prone water is one of the simplest methods for efficiency of flood. Identification of suitable areas for flood spreading by traditional methods usually is very expensive and takes up time. Using GIS and RS can reduce such costs and increase the speed and accuracy. The study area is part of the provinces of Khorasan Razavi and north Khorasan which included the cities of Sabzevar, Esferayen, Jagarm, Kashmar, Bardeskan and Khalilabad. In this study, seven layers, including units of the quaternary deposits, limitation of land use, slope, infiltration rate, runoff, storage coefficient and bed rock depth were selected and analyzed. Map of quaternary deposits was prepared from geological map at scale of 1:250000 and controlled by photo-interpretation. 43 sites were selected by field survey. A Land use restriction was prepared by field Investigation and visual interpretation of satellite images. The slope map was obtained by GIS method, using digital topographic map of the area with 100m interval and 30m Pixel size. Infiltration rate in each area was calculated by double ring test and geoelectric study was used for bed rock depth estimation. Also storage coefficient for each site was calculated by typical table related on soil texture using soil sampling to a depth of one meter. And finally volumes of overland flow were calculated for all sites by Jasten method. Booleain logic, index overlay and fuzzy logic were selected and tested in those areas to mapping suitable areas for flood spreading, using the weighting method. The results show that the fuzzy sum is the best and visual interpretation of RGB742 Integrating GIS, is more suitable to identify and prioritize areas prone to spreading.

Unfortunately the groundwater balance in all plains of Chaharmahal va Bakhtiari province is negative. The area of this province is only 1% of Iran Country, whereas it has 10% of water resources in this country. So, flood spreading will be helpful both in increasing the water table and flood control. Hence this research carried out to determine the most suitable areas for flood spreading in Kiar, Mizdej, Sefiddasht and Borujen plains. Slope, infiltration rate, alluvial thickness, alluvial quality and land use factors were explored as affective parameters in flood spreading. These parameters were explored, classified, weighted and overlaid using GIS system. Boolean logic, overlay Index and Fuzzy clustering methods were used to overlay these layers and the study areas were divided into two suitable and unsuitable classes for flood spreading. Results showed that based on overlay Index, Boolean logic and Fuzzy clustering 10.85%, 10% and 14.4 % of study area was suitable for flood spreading, respectively.  Infiltration rate was recognized as most limiting parameter among explored parameters that it due clay texture of soil in most parts of province. Alluvial thickness was recognized as another limiting factor for water spreading in Chaharmahal va Bakhtiari province.  

Following technological advancements and integrated municipal solid waste management in recent decades، various methods such as recycling، biotreatment، thermal treatment، and sanitary landfills have been developed and employed. Creating sanitary landfills is a major strategy in the integrated solid waste management hierarchy. It is cheaper and thus more common than other disposal methods. Selecting a suitable solid waste landfill site can prevent adverse ecological and socioeconomic effects. Landfill site selection requires the analysis of spatial data، regulations، and accepted criteria. The present study aimed to use the geographic information system and the analytic hierarchy process to identify an appropriate landfill site for municipal solid wastes in Najafabad (Isfahan، Iran). Environmental and socioeconomic criteria were evaluated through different information layers in the Boolean and fuzzy logics. The analytical hierarchy process was applied for weighing the fuzzy information layers. Subsequently، two suitable sites were identified by superimposing the maps from the Boolean and fuzzy logics and considering the minimum required landfill area for 20 years. However، proximity of these two sites to Tiran (a nearby city) made them undesirable landfill sites for Najafabad. Therefore، due to the existing restrictions in Najafabad، the possibility of creating landfill sites in common with adjacent cities should be further investigated.

over-exploitation of groundwater resources in Chaharmahal va Bakhtiari province led to prohibition of some plains in this province. One of these plains is Sefiddasht aquifer. Artificial recharge can be an effective method to raise the groundwater table and resolve the groundwater crisis in this province. The most important step for successful accomplishment of artificial recharge is locating suitable areas for artificial recharge. In this research, Slope, surface infiltration, alluvial thickness, alluvial quality and land use parameters were analyzed, classified and map of every parameter prepared using GIS. To overlay the affective parameters in artificial recharge, there were used Boolean and Fuzzy models. Results showed that 1.43% and 9.97% of Sefiddasht aquifer are suitable for artificial recharge based on Boolean and Fuzzy models, respectively. Using land use layer, these values decreased to 0.92% and 4.12% based on Boolean and Fuzzy models, respectively. So, land use is a limitative parameter in Sefiddasht aquifer.

The present study were conducted to determine the potential habitat of olive (Olea europea L.) species adapted to Mediterranean climate in order to expand the native and man-made forests of Chaharmahal va Bakhtiary province using Geographic information systems. The first step of the project was to collect the athand data and maps. Then three different data layers were extracted from topographic maps with 1:25,000 scales. For climatic sorting, the province was divided into three homogenous sub-regions and regressions models were calculated. The required climatologically layers were created through DEM for various dry months. Digitizing the available existing soil maps from various sources led to six layers in data base. The land-use layers were produced in eight layers including irrigated agriculture lands, rain fed agriculture lands, range lands, forest lands, agro forestry lands, bare rock lands, urban lands and other lands. Considering the ecological requirements of the selected species, the produced environmental data layers were combined with Boolean and Fuzzy logics to depict the potential habitat. The areas of these sites were 8708 and 7238 ha with Boolean and Fuzzy method, respectively which decreased to 693 and 2010 ha after considering soil texture limitations.

Precision farming aims to optimize field-level management by providing information on production rate, crop needs, nutrients, pest/disease control, environmental contamination, timing of field practices, soil organic matter and irrigation. Remote sensing and GIS have made huge impacts on agricultural industry by monitoring and managing agricultural lands. Using vegetation indices have been widely used for quantifying net annual production on different scales. The aim of this study was to find a rapid method with acceptable precision for the identification and classification of agricultural lands under cultivation (wheat and barley, alfalfa and potatoes). We used multi-temporal AWiFS data and applied Boolean logic and unsupervised classification. Results indicated that Boolean logic approach had a higher accuracy and precision in comparison to unsupervised classification, although it is more complicated and time consuming.

In the present study، Analytic Hierarchy Process method was used for weighting different assessed criteria for land suitability of irrigated wheat and the results obtained from fuzzy methods compared with those from conventional methods. Comparison of fuzzy and parametric land indices showed that fuzzy approach has increased the land indices in all of land units. The correlation coefficient between land index and observed yield in the study area for fuzzy approach based on AHP method and parametric approach were 0. 91 and 0. 87، respectively. Although، the fuzzy set approach offers the higher accuracy for land suitability assessment، the most critical issue in its application to land suitability assessment remains the choice of membership functions، cross-over points and weight values for different land characteristics.