The Examination of the Landscape Metrics Changes Using Urban-Rural Gradiant Analysis Method: The Case Study of Tehran Metropolis

The detection of urban landscape changes in urban areas is of utmost importance for the maintenance of the safety of environment and the promotion of sustainable development. To this end, the consideration of the spatial metrics capabilities to describe the landscape structure can be a valuable move to identify the growth models in metropolises. The purpose of this study was to provide the urban-rural gradient analysis of the landscape metrics in Tehran metropolis in the year 2018 as well as the analysis of their change trend in order to investigate the spatial-chronological changes in the landscape. In order to analyze the metrics, the moving window method was used at landscape and class levels. To this end, Landsat 8 satellite images were used, and the landcover was divided into human-made, open, vegetation, and water lands in a supervised manner. As with the gradient analysis, transects with 4km*4km dimensions at four directions – namely center-northeast, center-southeast, center-northwest, and center-southwest were directed from District 12 of Tehran Municipality in GIS 10.2 software. The results showed that at the landscape level, the closer we go to the business center of Tehran Metropolis, the number and density of patches increase, while the closer we go to rural areas the average index of landscape shape has relatively uniform changes. At the class level, the more distant we get from the business center of Tehran metropolis, the percentage of human-made patches and open lands increases and that of the vegetation patches decreases. Then, it might be concluded that urban development has brought about an increase in the density of patches in landscape, such that in the central transect, the continuity of landscape is reduced, and the fragmentation of the structural elements of landscape is increased. The land use changes have led to the expansion of the city toward the country and have negatively affected the vegetation and water resources.