Assessment of the Effective Factors to Determine the Capacity of Building Density in Historical Areas (Case Study: Urmia City)

Introduction To determine optimal building density, we have to consider the capacities of city and effective indicators. The suitable density is a balance between population, building density and capacity of the city. Several factors are required to determine the density in urban areas. This is affected by natural or physical factors and economic, social and cultural, environmental, technological and national policies of urbanization.  Today, non- scientific views to determine the proposed building density of urmia city is purposed with geographical, economic, population, physical, transportation, facilities and environmental features. This causes unethical loading of building density especially in historical areas. It has created problems such as traffic, dominance of buildings, lack of facilities, ghosting and etc. This can also offer practical and scientific methods as a viable solution for solving this problem. In any case, solution of this challenge is comprehensive and require multi-dimensional look to determine the building density in the historical area. In other words, optimal building density can show the physical identity of historical areas of Urmia city. To determine the density, it depends on privacy of historical monuments and capacity of historical areas effective indicators in the determination of density. The purpose of this study is the modeling of building density in historical areas of Urmia city on the basis of its capacity. Methodology This is an applied research with a descriptive-analytical methodology. Collection of information is conducted through library and field studies. After studying related references with building density, effective indicators are applied to determine building density for the historical areas of Urmia city. We have selected 10 indicators from different effective factors on building density to analyze the data. These indicators are population density, road width, plot area, number of floors, building density, the average price of land, existence of green space, existence of arid lands, existence of sewage facilities and privacy monuments. These effective indicators in determining building density have different importance factor, so in this research it has been used from elite opinions in order to determine the weight (importance factor) of indicators via AHP in Expert Choice.  The compatibility of the pairwise comparison is 0.08 and  acceptable for further analysis. In order to perform spatial analysis, the information layers have been digitized and editted in GIS and converted into Raster in Idrisi Selva and Global Mapper. Standardization of indicators has been conducted via Boolean method and Fuzzy functions according to the relation of each indicator with the goal of research. In next step, indicators have been combinedfor measuring the capacity of building density in Urmia city.  Results and discussion According to the results of AHP method, the maximum weight of 0.320 is related to privacy of historical monuments indicator and the minimum weight of 0.033 to the existence of arid lands. After extracting the weight of indicators, of information layers has prepared in GIS for standardization of layers. The obtained results from combination of the 10 indicators  show that 9% of historical areas in terms of the capacity of building density have low capacity of density, 18% have middle capacity of density, and others have high capacity of density. Application of these scientific methods can help urban experts and managements to offer ideal density model for loading of building density in the historical areas. The ideal density model is a model  to adjust densities in different aspects including image of city, balance in urban services, order in traffic and etc. Conclusion Creation of new buildings with an optimal building density with maintaining physical identity of historical areas depend on the respect for the privacy of the historical monuments, the capacity of historical areas and  effective indicators. Measuring the capacity is a fundamental principal in dealing with urban issues used in determining ideal density. . Therefore, given the effective indicators in determining density and measuring the capacity of historical areas in Urmia city, it can be acknowledged that the areas have the capability for increasing density based on capacities and privacy of historical monuments.