Analysis of Spatial Fragmentation in the Spatial Organization of Yazd Integrated approach using Network Analysis and Space Syntax

One of the critical issues associated with sustainability in the twenty-first century is how cities grow and develop in the space. Rapid urban growth and physical development of cities Cause disintegration of the spatial organization of cities and finally spatial inequality between urban spaces. A phenomenon that can be considered as spatial segregation or fragmentation in the urban space. So accepting the principle that sustainable development requires a coherent and balanced spatial structure of cities, Our modern cities Have been faced with Imbalance Service and fragmented urban growth, So that it can show appearance instability in the cities, such as poverty and informal settlements, spatial and social gaps and a lack of cohesion, the excessive density, traffic and environmental pollution, etc. Urban spatial structure affected by road network and the main urban landuses Particularly Urban Public Services. The objective of this research is finding spatial fragmentation based on distribution of public services and the spatial structure of urban road network in Yazd city.
To perform this analysis with using GIS 10, Yazd block polygon layer and Linear street network layer are used. To analyze the level of public services, network analysis technique with 10 variables(educational and cultural, health, sporting, shopping centers, urban facilities, office services, parks, police, passenger terminals) and to analyze the spatial organization of urban spatial structure, Space Syntax technique with 5 variables (global and local integration, connect, control and intelligibility) are used. This analysis has been made by using axwoman6 extension in Arc GIS 10 software. The method of Space Syntax is very suitable technique for the analysis of urban spatial structure Permeability. Integration is the main concept of configuration space. Integration of a point indicates its connection with the general structure or a subset of it.
Since the value of the variables is different, the Fuzzy Delphi technique has been used for weighting them. The Fuzzy Delphi is the combination of Delphi method and analytic hierarchy process (AHP) in fuzzy environment. In this method, such as AHP weighting parameters is done based on the Pairwise Comparison Matrix. So Indicators weighted by 10 urban professionals who have knowledge of the physical space in Yazd.
Finally using Kernel Density analysis to analyze patterns of spatial fragmentation and Hot spot analysis to understand the spatial clustering and focused fragmentation or integration in spatial structure of Yazd.
Overlapping Space Syntax parameters in Yazd city indicate that both north-south and east-west crossing, that they almost cover the whole city, are the most integration crossing in the city. As a result, these streets form the city backbone and considered as the main factor of the urban spatial organization coherence. Thus it can be argued that the more spaces between these structures and other urban spaces, Build more isolated areas or spatial separation in the city space. The results of Kernel Density analysis of space syntax results, Represents the spatial coherence in downtown and with Away from the downtown towards the periphery, reduce spatial integration and increase Spatial segregation and greater disintegration, especially in margin neighborhoods southwest of the city can be seen.
Simultaneously, the results of network analysis show Rich areas in inner urban spatial and deprived areas in the newly developed part of the city. The old and historical districts are in the central city of Yazd and much of the city's worn out neighborhoods are in this districts. Worn out districts at higher level of service than other urban areas in this part of the city are the reasons of scattered development, especially on the South West and West edge of the city, So that the level of service in the parts of these neighborhoods is zero.
In hot spot clustering, although the central area of the city and the historical context in terms of service level have formed hot spots, but in terms of the spatial structure of the spatial concentration of low and middle scores have formed. Also, some marginal neighborhoods in terms of service levels are at low level, but in terms of the integration of the spatial structure have formed hot spots. This phenomenon may be caused by organic fabric of historic neighborhoods and checked fabric of marginal areas. The checked fabric is more permeable than the organic fabric.
Conclusion;Distribution of urban services as one of the main indicators of the citizen welfare and shaping urban spatial structure and activity is one of the important problems facing most developed and developing countries. The results of this study indicate that while some downtown neighborhoods are parts of historical and worn-out textures, but in terms of service levels have higher score to other places around the city, however due to lack of quality of life suffering from time-warning. Lack of coherence and integration of the internal structure of these neighborhoods with the whole structure of the city is the reason for Lack of quality space in city central neighborhoods. Perhaps the historic fabric neighborhoods isolated socially from the rest of the city, but due to both physical and spatial relationships and integration with the main structure of the city have no significant difference (although regeneration is necessary, particularly in the internal spaces areas). Thus the spatial organization of historical fabric is not the cause of exhaustion this districts. But the main reasons are social and economic problems. Also the spaces, which are separated from the spatial organization and formed cold spots, are populated neighborhoods and developing.
On the other hand, disintegration in the spatial structure of the city is the influential factor in the high horizontal development of the city. Hence the creation and redefining integration of urban spatial organization is essential to prevent the scattered development in the city.