Development of the area of supply and demand of urban parks with a spatial distribution coefficient - Case study: Region 1 of Tehran

One of the most important consequences of the rapid growth of urbanization and the physical development of Iranian cities in recent decades has been the disintegration of the distribution system of urban service centers. Urban parks and green spaces played a special role in creating this social inequality for citizens' access to city services. Park green spaces (PGS) are considered essential public infrastructure due to the benefits they have for urban residents. Such benefits include recreation, viewing natural landscapes, protecting the urban environment, preventing disasters, and improving the quality of life. According to the worrying consequences of the urban landscape planners regarding the imbalance in the spatial distribution of urban green spaces, it seems that the ideas and theories attributed to urban greening and universal access to desirability Green cities have the potential to act as a decisive force in the main agenda. Similar to the ideal of "public goods" and the diffuse benefits of access, green goals can serve as a means to de-emphasize asymmetric power relations and conflicts over competing resources, which risk re-creating unjust outcomes. In this article, the ASD index (Equation1) of Lee and Hong (2013) is used to measure the level of shortage or excess supply of urban park services. One of the innovative aspects of this research is the use of the distributive justice index to measure ASD, which is introduced as new ASD. With the help of this index, it is possible to find out how effective each park is based on the index received through the calculations made in the supply and demand model. In other words, this article measures the quality of locating parks in the supply and demand model with the effect of their spatial distribution justice. This causes that in addition to the longitudinal distance between parks and residential blocks, the factors affecting their public services will also be involved in the calculations to bring the findings closer to the current situation. Many studies have been conducted on the topic under discussion.

This study is an information modeling research. For that purpose, it's practical and developmental research to measure the degree of the supply shortage or demand excess for urban park facilities. In other words, the present study uses situational weight index and distributive justice for ASD. This research is mixed regarding data collection methods, relies on library methods to review resources, selects 50 points for field observations to collect location information, and extracts the required parameters to create a database based on reference land information. This research will be dependent on the modeling analysis method and using GIS analysis functions. The analysis of input data, including qualitative and quantitative information, is performed using standard coding and weighting methods. ASDi, which is the quantitative difference between supply and demand in park services per unit area ('area' hereafter), is defined as follows .This research was used by combining the positional weight index and distribution justice for ASD to explain the new ASD index(Equation2).
Equation. 

 To measure the spatial justice of an urban park, mathematical communications and formulas will be used in this study, which the authors optimize to suit the specific conditions of the parks. Indicators are:› Determining the share of each park in the population under the sphere of influence,   Measuring the efficiency of parks,  The distance of residential blocks from parks, The population of residential blocks in the sphere of influence of parks.

The findings of this study show that parks that have high park efficiency, the final branches of spatial justice of parks are also high, with the difference in areas where Metropolitan and Regional parks are adjacent to neighborhood parks. The final index of spatial justice improves and expands the parks relative to their efficiency.Based on the empirical analysis, the spatial disparities can be even greater when service availability and population demand are high. City planners should decide to build new parks by considering areas where demand is higher than the supply, not just based on whether there are many parks nearby because residents in the densely populated areas may suffer from a lack of services even though many parks are located nearby.The “new ASD” method has advantages for studying the parks of Region 1 of Tehran, which can be summarized as follows:New ASD can be interpreted intuitively because the results are measured in square meters, which should provide more parking spaces or the number of people at risk of park shortages. The per capita green space parameter allows the demand unit to be equated with supply, allowing planners to easily calculate the size of parks that should be more in priority and low supply areas.The results of the analysis can be obtained based on determining the geographical coverage of the park services. Based on the planning information drawn using legal criteria, planners can support their arguments about the location of other parks by recognizing spatial inequality.Although different social groups were not considered in the analysis, like other studies that looked at ethnic subclasses to highlight park service inequality among different ethnic groups, the methodological process of new ASD estimation can be easily extended to apply to different social groups. For example, some landscape planners In Tehran, they may be interested in studying spatial inequality, for example, people with disabilities, different age groups, or men and women separately.