land suitability for urban and industrial development by a proposal model, case study: jahrom township, iran

introduction urban planning is the process of influencing, controlling or directing changes in the use of land overtime and space in an urban area. therefore, it involves plan formulationand development control. to achieve this, concept of sustainable development must be addressed to remedy social inequities and environmental damage, while maintaining a sound economic base. the sustainable development or best use of the land will be carried out by assigning the land use zones on the basis of capability, compatibility, and use of proper technology and measures to protect environmental degradability. in the past, planners and developers were increasingly ignoring the natural environment and, thus, causing damage to it. nowadays, the excessive pressure by human on lands is very serious problem for land degradation. for this reasons, the land must be properly planned to determine where human want to live, particularly. hence, evaluation of urban development suitability plays a fundamental role in urban planning and enhancement. land suitability assessment is the process which determines the fitness of a given tract of land for a defined use, usually among multiple competing uses. in addition, selection ofproper method of evaluation for planning is also very important. evaluation based on boolean method in classic methods like the fao model for land evaluation using maximum limitation, make the classification quite strict. in many cases, these models have been applied incorrectly and with dubious results. the goal of current study is the implementation of boolean ecological model and comparison to proposed quantitative methods in urban andindustrial planning.          material and methods the study area (jahrom township) is located in the fars province in the southern iran. this township has an area of ​​5436 square kilometers and is placed at latitude 28°19ˊto 29°10ˊnorth and longitude 52°45ˊto 54°4ˊ. the average height is about 1050 m. the climate is warm and in mountainous areas is generally moderate. six evaluation methods were conducted. they areincluding:   iranian evaluation model of ecological capability by boolean: iranian evaluation model ofecological capabilityis an iranian model for urban and industrial development use. it is formed of 3 classes that ecological potential is reduced by increasing capability number of classes.   revised iranian evaluation model of ecological capability by boolean: in the revised method, we have defined the criteria based on table1.   evaluation of model based on arithmetic mean: in the arithmetic mean method, the scores related to the parameters were averaged. evaluation of model based on geometric mean instead of boolean logic: according to criteria, every index was given the weight between 0 to 2, that 0 states none-suitability of ecological condition and 2 shows the most suitable of ecological condition for urban planning. then, every criterion was calculated based on geometric mean of the indicators according to equation1:           equation1: criterion_ x= [(layer-1)*(layer-2)…*(layer-n)] ^ l/n   where criterion _ x is defined as criterion, layer is an indicator map of criterion, and n is number of used indicators. then, the criteria were multiplied through geometric mean (equation2). equation 2: final criterion = [(layer-1)*(layer-2)…*(layer-n)] ^ l/n   where final criterion is final layer of ecological capability and n is number of used criteria. then, qualitative and suitability classes of ecological capability were defined for urban planning in the study area in a gis (table 2).   calibration model of the last one: in order to evaluate accuracy of the obtained maps quantitatively, it is compared pixel by pixel to ground reality (current land use) in error matrix. in final step, calibration was done based on accordance to ground reality (current land use).   evaluation of industrial use based on calibrated and limitation maps.   table1. factors affecting urban and industrial planning main criteria indicators (layers) topography slope, land form climate precipitation, temperature, relative humid, wind speed soil texture, depth, drainage, erosion, gravel, percent, granulating, evolution geology lithology + hydrology vegetation vegetation cover water quantity of water   table 2. suitability classes in the capability maps and models for urban planning regarding the scores of polygons   suitability classes   their score good (1) moderate (2) not suitable (3) 1.5-2 0.5 - 1.5 < 0.5     results and discussion in this research, suitability maps and spatial distribution derived from different models were obtained. the model by best accuracy (calibrated model) and industrial development map were indicatedin figure 1. the results representedthat calibrated revised method (3 classes) using geometric mean evaluation is the best model among the different used models (table 3). this indicates calibrated revised method (3 classes) using geometric mean evaluation can be a useful model tofind potential area for urban planning. it should be noted that the classic methods like the fao model for land evaluation using maximum limitation make the classification quite strict. but proposed method is more flexible for evaluation regarding to kind of evaluation that it doesn&apos;t depend only on one parameter that is observed in methods using boolean approach. also, geometry mean method is reduced high impact of some factors such as the soil. topography with two indiceshas a measure of weight equal to the soil factor. additionally, the average of ecological conditions is also considered. boolean model is based on maximum limitation.   figure1. the calibrated model by maximum accuracy and industrial development maps   table 3.accuracy assessment in the used models model type iranian evaluation model of ecological capability revised methods (3 classes) booleanlogic averaged based arithmetic mean geo_ mean calibration overall accuracy (%) 54 54 42 86 87 kappa coefficient 0.32 0.32 0.24 0.75 0.77 inclassindex 0 0 3.93 4.36 4.56          conclusion the planning of urban land uses is the most important and difficult urban programs. thus, it changes all urban planning including future city. the gis based multi criteria evaluation technique is very simple and flexible which can be used to analyze the potential sites for urban development. this model can also encourage public participation in the urban decision making process and assist various planners and authorities to formulate suitable plan for sustained development of the region. hence, the results of this study are suggesting to managers and other stakeholders so approach that is scientifically complete, sound and practical.