جستجوی مقالات مرتبط با کلیدواژه « پراکنده رویی » در نشریات گروه « هنر و معماری »

The growth and expansion of metropolitan areas as a global phenomenon is becoming the dominant form of urbanization, especially in developing countries. Despite the increasing importance of this form of urban growth, not many studies have been carried out regarding the multidimensional dynamics of the factors and mechanisms that stimulate urban-regional sprawl. In the current research, the structures and mechanisms affecting the informal processes that generate spatial expansion of the Tehran metropolitan region have been analyzed. This research is qualitative and in-depth semi-structured interviews were used to collect information. The data analysis was based on the constructivist Grounded Theory approach. Research participants included university professors, city managers, and experts from the municipalities, governorships, road and urban development departments, National Land and Housing Organization, Agriculture-Jahad, Natural Resources departments, etc. The sampling method was targeted non-random and based on snowball sampling. According to the results, 289 key phrases were identified in the initial coding, 130 concepts were identified in the centralized coding, 64 subcategories were identified in the axial coding, and finally, 34 broad main categories were identified in the theoretical coding. In total, according to the output of theoretical coding, all broad main categories in the form of 7 integrated main categories formed the theoretical model of the research. According to data analysis, economic and political economy structures, fundamental structures, legal structures, and judicial structures at the macro level and organizational-institutional structures and private and social sectors at the middle level affect the informal processes underlying land acquisition and the spatial expansion of the Tehran metropolitan region.

The central city-region of Mazandaran Province, including the cities of Sari, Qaemshahr, Babol, and Amol, contains more than 53% of the population in only 30% of its area. Based on the set of issues that the spatial patterns of sprawling have brought about in the central city-region of Mazandaran Province, a research gap seems to be there in the presentation of a conceptual model of the relations governing the causes of sprawling and the consequences in this city-region. This research attempts to take an effective step in that regard.

Theoretical Framework:

There are two perspectives on the issue of sprawling: spatial and non-spatial. From the spatial point of view, issues such as land use changes, housing and land demands, transportation and infrastructure development, and inefficient land development have been raised, which directly or indirectly affect the causes and consequences of sprawling. From the non-spatial point of view, on the other hand, socio-demographic, economic, environmental, and management and supervisory system issues are discussed, the impacts of which on the causes and consequences of sprawling cannot be ignored. In line with the diversity in the spatial patterns of this type of growth in the urban and regional space, the causes of occurrence and the consequences arising from the spatial patterns of sprawling are different, an issue that is controversial due to the dynamic nature of the phenomenon. If sprawling is accompanied by poor control and supervision, there will be many negative consequences such as development inefficiency, extensive change in land use, destruction and waste of natural lands, excessive growth, increase in land and housing prices, formation and prosperity of temporary residence and second housing patterns, unplanned formation of residential centers, spatial imbalance, change in peri-urban and rural landscape, and combination of urban and rural boundaries. This causes many more issues in the physical and spatial subsystem of the planning environment and also has negative effects on spatial development processes.

The purpose of this study is to investigate the causes of sprawling by planning subsystems and to analyze the consequences of sprawling and achieve the underlying, causal, and continuity conditions in the city-region under study. This applied descriptive-analytical survey adopts a library-documentary method of data collection.

In the first part, the experts were provided with a questionnaire on the variables affecting sprawling extracted from studies around the world using purposive sampling, and the results were then analyzed using the fuzzy Delphi method. In the second part, structured interviews were made with the experts in the grounded theory system using the MAXQDA software, and they were then reviewed, analyzed, and coded. To investigate the causes of sprawling, 38 variables on 6 factors were provided to 25 experts who were selected based on purposive sampling. We used semi-structured interviews with 34 participants in the study area in order to analyze the consequences of sprawling, studied the spatial consequences of sprawling in the city-region, and specified 249 initial codes and 28 focal codes. Then, we formulated with the technique of continuous comparison the underlying conditions of development and economic structure change, the causal conditions of the inefficiency of the management and supervision system, the conditions to continue the transformation of the local community and destroy the natural structure, the consequences of change in the physical and spatial structure of the extraction area, and the grounded theory of the consequences of sprawling.

The most common causes of sprawling in the study area include per capita household income, land and housing trade, and land prices. In the analysis of the consequences of sprawling, we explained the background conditions for economic development and restructuring, the causal conditions of the inefficiency of the management and supervision system, the conditions of continuity including the transformation of the indigenous community and the destruction of the natural structure, and the consequences of physical and spatial restructuring of the region. To interrupt the process of formation and reduce the negative effects of sprawling, proposals were made on attempts to regulate and reform the decision-making structure, apply economic policies and adjust the market, slow down the accelerated process of destruction of the natural environment, improve the structure of regional planning (draft a codified, updated land use plan, apply detailed policies and ones to avoid promotion of land speculation, avoid provision of construction and building permits for peri-urban lands in the study area, partition natural lands and prioritize future developments in low-value lands, adopt approaches to endogenous development, development in brown lands, and intermediate development, and achieve a sustainable local society.

The rapid growth of cities around the world occurred at a time when cities were unable to provide services to their rapidly growing urban population, leading to the dispersal of land on the edge of cities, the proliferation of illegal and marginal settlements. Considering the physical development of the city is a basic necessity in urban development programs. In Iran, the rapid physical expansion of cities in the form of unplanned and unbalanced growth for various reasons, including involuntary migration, is one of the main problems of cities, as a result of which the phenomenon of urban sprawl occurs. The purpose of this study is to identify and analyze the factors affecting the physical-spatial development of Sari. The present applied research is analytical-descriptive. Theoretical data have been prepared through documentary method and experimental data have been prepared through survey method. In preparing the development drivers, the Delphi method has been used. According to the above criteria, 20 experts and specialists of academic and research centers have been selected to participate in the research. In data processing, structural interaction analysis method has been used in MIC MAC Software. Based on the obtained results, the most important factors affecting the growth of Sari spatial form include factors such as inefficient urban management, high quality agricultural land, land price, weakness and non-observance of communication network hierarchy, land and housing transfer policy, as well as being the center of the province and equipped it with superior regional services.

Urban sprawl phenomenon is a multidimensional phenomenon that has many consequences, especially in social and public health aspects. The purpose of the present research is to investigate the sprawl phenomena in neighborhoods and their impact on the physical activity in Ahvaz. The research is applied in terms of purpose and in terms of method it is descriptive-analytical. Survey data in the scattered section for 116 neighborhoods were extracted from the statistical block and from land-use layer of Ahvaz city. 17 indices including population density, housing density, household density, net residential density, number of mixed land use parcels per neighborhood…. were used. The data were analyzed using ArcGIS software and DEMATEL (weighting) Vikor (ranking) techniques. In the second part (citizens' physical activity) a questionnaire was used to collect data. The statistical population is the residents of two neighborhoods that are in the first and last ranks in the sprawl form. The results show that Kianshahr neighborhood and Zeytoon Karmandi neighborhood are in the last place in terms of sprawl rate. The results of the physical activity questionnaire in these two neighborhoods showed that physical activity and sport activity of Zeytoon Karmandi neighborhood were higher than Kianshahr neighborhood. Therefore, sprawl in Ahwaz city reduces physical activity.

After the Industrial Revolution, advancement in industry and technology was coupled with population growth, and rural-urban immigration caused the extreme expansion of cities. Moreover, the rapid growth of urbanization in coastal areas and conflict of interest between the stakeholders has imposed extreme ecological pressure on this fragile ecosystem, which indicates the contrast between cities and coastal environments. According to records from the Statistical Centre of Iran, the coastal city of Deylam, Iran, located in Bushehr Province, has been struggling with population and immigration growth during the past six decades. Since the common expansion pattern of coastal cities is linear, where they are distributed along the coast, any attempt against the urban sprawl of coastal cities will clearly benefit the coastal ecosystem. In this research, the urban sprawl of Deylam was investigated for an approximate time span of ten years using quantitative data and a descriptive-analytical method. For this purpose, the prevalence of urban sprawl in the area under investigation was first verified using Shannon’s entropy method. Subsequently, the share of horizontal urban growth, which has faced Deylam with urban sprawl, was specified using the Holdren model. Next, the rate of horizontal growth for the period of investigation was calculated for the first time through application of the Digital Shoreline Analysis System to a study of horizontal urban growth. Eventually, the optimum size of Deylam  for the investigation period was obtained through subtraction of the share of growth calculated by the Holdren model from the total growth of the city, provided then through maps generated using ArcGIS 10. According to the calculations made using Shannon’s entropy, Deylam was expanded extensively at the beginning of the investigation period (i.e., February 16, 2005), undergoing 80.14 percent its maximum possible urban sprawl. Moreover, 62.9 percent of the urban growth of the city in the investigation period resulted from the population growth, based on the Holdren model; therefore, 37.1 percent of the total growth is responsible for the urban sprawl of the city. The results demonstrated that Deylam has experienced growth rates of 19.08 and 23.11 m/year at its northern and southern edges with standard deviations of 4.5 and 4.1, respectively. At the northern edge, the growth rate of 7.08 m/year is due to the urban sprawl, and the 12-m/year rate has resulted from the population growth.  Along the same lines at the southern edge of the city, the growth rate of 8.57 m/year is due to the urban sprawl, and the 14.54-m/year rate has resulted from the population growth. The western and eastern edges of Deylam have not developed during the investigation period, because there have been natural barriers in these parts. Since the presented framework, implemented in this study, is easy to apply, and the procedure of calculation is clear, it may provide contributions in projects involving prevention of urban sprawl.

Physical development of cities in Iran often spread out in the form of horizontal and fragmented expansion which resulted in the negative impacts and instability of cities in last decade .The Urban Sprawl known as an environmental phenomenon in the country and required to reflection to understand the effective factors strategies for managing it and moving toward urban sustainability. In this research we tried to study the existing global experiences and theories by determining the indicators Urban Sprawl the Urmia city explained and extent in different parts to make a solution to present sustainable city. For recognition nature of Urban Sprawl with Check out the different views, indicator of Urban Sprawl and technique of measurement and research method extract and match with Iran and Urmia conditions and 26 indexes have been selected. By studying the physical extension of the city and proving Urban Sprawl evidence area of city from the terms of desired properties divided to 39 homogeneous area and 26 index based on these area derivation form the various sources and with method of agent analysis in format of 7 main elements with 88.34 percent of various of outspreading explained, seamlessly take down with GIS in city area which form the five levels divided form so low to so much. Studying different area of Urmia form the representative indices show that weakness of user disorder and low density, the main activity space with least weight and importance. In the area which the points of factors in this higher (10-8) Urban Sprawl is so high (new developments contain 4-5-34- 35 regions) and area which total points in these low (0-2) have a lowest Urban Sprawl (old texture contains 18-19-20 regions) by creating interactive maps of Seven factors, approach of sustainability of city with moderating the effect of factors and prioritization of areas act and presented.

Sprawl is one of the forms of expansion that has entered the literature of urban management and planning in the last half-century. Some Iranian cities have experienced this kind of expansion at a rapid pace. Babol is one of the medium-sized cities of Iran. The aim of this study is understand the pattern of the expansion of this city from 1957 to 2017 and its effect on the structural and functional changes of villages around and the Siakolamahaleh village. The statistical population of this research is the city of Babol and Siakolamahaleh village. The period of this research is from 1957 to 2017. Data gathering were done via documentary and field work technique. Data analysis demand application of GIS in order to analyze the rate, direction, and form of Babol sprawl between 1957- 2017. This is further followed by application of Holdren model regarding computation of degree of sprawl in Babol. Calculating the distribution of this city using the Holdren model shows that over the entire period from 1957 to 2017, approximately 74% of the city's horizontal growth has been driven by population growth and 26% of it has been affected by dispersion. This trend has led to the integration of villages around the city. This dispersion is connected linearly in the north and south along the axes and separated by a physical alteration of its peripheral settlements. The village of Siakolamahaleh is one of the most important villages in this area.

Residential constructions with or even without plan have led to the expansion of cities and their peripheral areas into the agricultural lands of central city-region of Mazandaran province. The economic capacity of this region is based on the capacity of agricultural development. To preserve the national capital, a specific plan should be adopted to prevent the increasing destruction of the lands and the development of the buildings constructed on these lands. The current capacity has already been completely forgotten and undergone changes or even widespread degradation due to the development of the land and housing market. The purpose of this paper is to investigate the typology of spatial patterns of sprawl in central city-region of Mazandaran province. The research method is quantitative and the main data is summarized in terms of demographic and physical-spatial components to achieve the research objectives. The annual data on the population of rural and urban areas in the Statistical Yearbooks of Mazandaran Province from 1986 to 2016 was consulted to obtain demographic data. Physical-spatial data includes the data related to built-up lands during 1986-2016 (based on Landsat images and 1:25000 map of Mazandaran province development) and construction density in the study period. Other data was obtained from statistical and mathematical processing of demographic and physical-spatial data using GIS, ESRI, and the urban growth model. Then, the Kriging Estimator was used for the typology of macro-scale spatial models. Also, the urban growth form (UGF) was used for micro-scale spatial patterns. This model can identify 3 main types of sprawl, including linear, infill and leap-frog patterns, based on the development process perspective. The results of the research indicate that urban sprawl has increased on the macro scale during the studied period. In this sense, the spatial pattern in 1986 was focused on only three main urban centers with a sprawl in their peripheral lands, especially in the city of Sari. However, in 1996, due to the transformation of some rural centers into urban areas and the trend of development in the lands around urban centers, concentration in Babol increased, but only some parts of the lands of Babol and Qaemshahr underwent the sprawl phenomenon. This was the case up to 2006, but in 2016, along with the concentration of development in urban, peri-urban and rural lands, the sprawl phenomenon intensified with increasing values of the related variables. On the other hand, spatial patterns of sprawl from 1986 to 1996 (including intervals of 1986-1996 and 1996-2006) were linear on a micro scale, a line with an upward trend due to the development around the boundaries of urban settlements (peri-urban lands). However, in the period from 1986 to 1996, sprawled development tended to have an infill pattern, indicating the emergence of a combination of linear and infill patterns. In the period from 2006 to 2016, the spatial pattern of growth was also an infilled one. It should be noted that, in a separate study of urban and rural settlements of the studied city-region, different results were observed in urban lands. Thus, it can be concluded that the sprawl pattern in urban lands often follows a dispersed and linear pattern, while rural settlements have a linear and infill pattern. The sprawl pattern in the central city-region of Mazandaran has evolved as a result of the development of rural lands. Residential constructions with or even without plan have led to the expansion of cities and their peripheral areas into the agricultural lands of central city-region of Mazandaran province. The economic capacity of this region is based on the capacity of agricultural development. To preserve the national capital, a specific plan should be adopted to prevent the increasing destruction of the lands and the development of the buildings constructed on these lands. The current capacity has already been completely forgotten and undergone changes or even widespread degradation due to the development of the land and housing market. The purpose of this paper is to investigate the typology of spatial patterns of sprawl in central city-region of Mazandaran province. The research method is quantitative and the main data is summarized in terms of demographic and physical-spatial components to achieve the research objectives. 

Nowadays the urban growth pattern of cities is growing dramatically; and current suburbs of cities will form the inseparable components of the main city in the near future. In all cities of world vertical and horizontal urban growth have been one of the most important factors noticed by urban managers and planners. Urban growth is a spatial - structural process that refers to the increased importance of towns and cities as a concentration of population within a particular economy and society. Increase in urban points as quantitative issue shows itself in the forms of increase in population of cities and development in built up area scale. The unorganized physical growth of cities is due to their physical discrete and separate development which is mostly in form of forming individual and separate parts. Hence، analysis of the current physical status، and prediction of the future development of cities due to its influence on the politics and management of city and human resources، is of great importance. Regarding the numerous factors affecting the inharmonic physical urban growth، the present article has investigated the rate of urban horizontal growth from two aspects of area and direction. The research method in this article is analytical- comparative and with respect to the evolution of the physical- spatial pattern of Tabriz metropolitan in the 1956-2006 period. Shannon’s Entropy model is utilized for evaluation of the rate of the urban horizontal growth diversity. In order to use this model first we draw the complete and detailed plan of Tabriz city in concentric buffers with width of one kilometer between years 1956-2006 using Auto Cad software and the physical gravity center of Tabriz city which is the same center of cultural- historical part has been considered as basis for buffering modulation، and Sectoral- Geographical model is used for specification of urban growth directions.. In the next phase center of city gravity has drawn in the form of circle with determined diameter and the center of this circle was considered as basis for modulation of geographical sectors and sectoral buffering in 12 geographic directions. The attained results of analyzing the research findings has shown that the sprawl growth and diversity of inharmonic development has occurred in Tabriz metropolitan. The maximum of this rate has happened on the year 1996 and directions of horizontal urban growth are completely coincided on the margins of main connection corridors of city.

The term “urban sprawl” is often used as a synonym for undesired low-density or otherwise unplanned urban spatial development. More often, though, sprawl is defined in terms of “undesirable” land-use patterns—whether scattered development, leapfrog development (a type of scattered development that assumes a mono centric city), strip or ribbon development, or continuous low-density development. However, the precise definition, as well as its desirability, is debated. From mid of twenty century, urban sprawl has become as a main subject and challenge in spatial policy making agenda of most of governments. In this kind of urban expansion, land as a main source of development is utilized in a higher rate than population growth. Such kinds of development, for lack of mixed land use, lack of centrality and inefficiency in accessibility, etc. leads to wasting non-recyclable resources and energies (resources like land for developments and energy for center-periphery commuting) on the one hand, and polluting environment as their impacts on the other hand. However, intensity and substance and physical forms of urban Sprawl would be different dependent upon levels of economic and social development of countries and their planning system. Major factors which caused the urban sprawl in Iran were parallel with starting exogenous development process in the country. Rapid urbanization fueled by motorization, rapid growth of population and rural –urban immigration, central government ineffective land policy, land speculation, etc. prevent from infill development and led to land uselessness within cities as well as increasing urban sprawl in suburbs. All these processes led to a massive transformation of agricultural land into urban landuses all over the country and provided some evidences that urban is taking place as a pattern of development. So, it seems that the mentioned pattern in our country is different from its origins (in American cities). Although the urban sprawl began four decades ago in Iran, but has yetto be empirically measured or characterized. Present paper aims at defining and measuring the characteristics of urban sprawl in three middle range Iranian cities according to a preferred theoretical framework inferred from literature review. In case studies, the authors have used GIS based data and methods like factor analysis and SPSS for measuring their urban development characteristics and defining the areas that show higher indices of sprawl development. Research findings indicate that lack of centrality and low level of mixed land use are the main factors defining urban sprawl development in the case studies. This is in contrast with western countrie's situation in which low density development is the main characteristic of sprawl. The findings show that the highest rate of urban sprawl is observed in the areas of Sanandadj and Ardabil that were developed and affected directly by the governmental land policies.

The term sprawl has entered into urban planning literature since the middle of 20th century and nowadays it’s one of the main subjects of concern in many countries. Although the research on sprawl originated in the studies of the American cities, but it has been used in many different countries with various natures, indexes and results. The trend of expansion of cities and metropolitan areas has many positive and negative results and it depends on different geographic, economic, social and political characteristics of cities and metropolitan areas. Although our cities had experienced slow expansion long ago, but the concept of sprawl has entered into our planning literature now. Zanjan is one of the cities in our country that have had a rapid expansion in recent years and vast areas of the city have been built up recently. Findings show that the initial expansion of the city has been due to its physical position and its natural population growth, but over the time, the expansion of the city has been affected by various factors such as economy, urban development plans, policies and different groups that have brought about the sprawl phenomenon to the this city. In order to examine the sprawl phenomenon in Zanjan, based on Ewings findings his study of the American Metropolitan Areas, we chose ten variables that could depict the sprawl phenomenon in Zanjan city setting. Factor analysis was applied to these selected 10 variables to find the underlying dimensions of sprawl in the Zanjan city. Four factors were extracted, namely: density, mixture of land uses, centeredness and accessibility. The results of the factor analysis were transformed into maps using GIS software. The findings indicate that areas in the central parts of the city have the least rating of sprawl and it gets aggravated by moving away from the center, so that the most sprawls is seen in eastern, northeastern and western parts of the city. In addition, comparing sprawl and expansion process of the city in different years show that the central zones that had formed in the initial period, have low level of sprawl and the zones that have been built in recent years, tend to have sprawled most. It was seen that in recent years many causes have led to the sprawl in Zanjan City. Initial growth of the city was because of the geographic location of the city and the communication network that Zanjan is part of it and the icural growth of population. This growth obeyed natural and climatic characteristics, but over the time, the growth of the city was affected by some other factors such as economic affairs, policies, plans and various groups. Findings of this research support Ewing`s viewpoints and show that by considering sprawl characteristics and surveying the extracted factors and taking into consideration the elements that affect sprawl, we can control of the city growth in the future in similar instances by using appropriated policies.

Growth of sprawl particularly in metropolitan fringes has become as on of the complicated problems facing policy-making about spatial development in metropolitan regions. The present paper is aiming at examining and analyzing different socio-economic and political factors which impact on increasing sprawl in the framework of rival theories. It seems that obtaining an effective policy instrument for spatial development and its control, is not possible without recognition of sprawl factors, its mechanisms and impacts. Various research indicate that those factors such as existence of cheap land in urban fringes, weak control enforcement in outer areas of municipalities borders on land development, priority of suburban lifestyle particularly resulting from degradation of quality of life in core city, increase in private car ownership and development of public transit facilities, market failure of assessing total value of spaces, social costs of crowding into these areas, and specially political fragmentation have great influences on formation and fortification of sprawl in metropolitan regions.