عنوان مقاله [English]
Planning for urban density is one of the most important problems in contemporary urban planning at both national and universal level. Urbanized world - that is changing permanently - needs an optimum extent of urban density which can consider both quantitative (efficient use of land and urban infrastructures, reducing energy consumption, etc.) and qualitative requirements (such as providing desirable neighborhood, vitality, mobility, etc.) of urban planning.
On the one hand, fundamental role of building density as an appropriate instrument for substantiation of urban policies, in order to achieve urban sustainable development and on the other hand, slight success in urban plans in the field of building density due to lack of sufficient scientific basis researches to determine the density and the dominant view of economic to urban density in the Iranian urban policies, makes the building density distribution necessary. Principles and criteria for sustainable development should include all the factors influencing the density and dimensions of time, space and scale.
In order to achieve this goal ,this research seeks to identify the indicators affecting the distribution of building density in various social, economic and environmental dimensions, as well as the type and relationship between these indicators and, finally, how the distribution of building density is.
This paper in addition to prospecting indexes which affect the density distribution of construction, consider type and relationship among these indexes and finally, it will follow building density distribution in zones 9 and 11 in Mashhad using GIS.
Survey method is based on integrated analysis which is appropriate to the research objectives. In statistical analysis (non-spatial), multiple regression was used to test the correlation between independent and dependent variables. Hierarchical Analytic Method (AHP) was applied to determine the weight of criteria and sub-criteria. In spatial analysis, Index Overlay and Geographic Information System Spatial Analysis (GIS) tools were used.
Finally after the statistical and spatial analysis, the results confirm the significant relationship among indicators of economic, social, demographic, physical space, functional, environmental, as the independent variables and building density as the dependent variable.
The variables of correlation with building density in the study area are: residential land price, total residential density, population growth rate in the period under study, area of parts, quality of building, materials used in the household ( Skeletons and facades), old buildings, the existence of an erosive texture, the density of residential units per unit area, the location of facilities such as microwave radio stations and high power lines, access to commercial services in the neighborhood and district scale, and administrative services. The functional scale of the area and the city as well as the amount of access to the urban train stations, distance from traffic nodes, vulnerability to flood, earthquake, subsidence, landslide and fluidity, sewage network coverage, wastewater treatment and groundwater contamination are other factors. In the context of the effect of various factors on the distribution of building density, the economic index has the highest coefficient of importance for the integration of indicators. Then, environmental indicators, functional indicators, spatial indices, and social indicators have the most impact on the distribution of construction density Have studied in the field
The results of the proposed building density show that more than 45.12 percent of the study area is included maximum density of building and 35.21 percent of this area with a building density of the medium and 19.68 percent of it with a building density of the minimum. Maximum building density is focused in the center of study area and minimum building density is concentrated in south and southwest of study area. The southwest of the basin is due to low indicators of the quality of the texture stability (quality and history of the building, materials used in the building, the existence of an extinct texture and the aggregation of residential components) and, consequently, the low cost of residential land with minimal construction density. Also, in the southern part of the field, the main reason for the establishment of minimum construction density is the distance from services on different functional scale.