Object Based Analysis of Land Use/Land Cover Changes Caused by Construction: A Case Study in the Mehr Pardis Housing Area

The increasing population of the large cities has led to developing new constructions in areas around cities to create settlements for the overflow of the population.Such changes in the natural land cover not only disturb the heat balance, but also have negative effects on the landscape, energy efficiency, health and quality of human life. Therefore, it is important for urban planners and managers to be aware of the changes in land cover and land use, especially in metropolitan areas, during long-term periods of time, in order to evaluate and predict the problems caused by these changes. Multi-temporal remote sensing data are one the powerful tools fordetecting land use/cover changes due to the increasing urban growth and then, for updating the three dimensional city models.

In this paper, the impact of Mehr Pardis housing construction is investigated on the land use/cover changes. The proposed land use/ cover change detection strategy in this paper is a post-classification method based on performing object based image analysis procedure. For this reason, Landsat satellite images have been used in 17 years’ time interval, between 2002 and 2019. After performing initial image processing and image segmentation, the three object classes of residential buildings, vegetation, and soil were identified by the object based image analysis procedure. Then, post-classification change detection performed on the generated object based classification maps of both 2002 and 2019 epochs. For change detection in this research, while comparing and contrasting the classes of recognized objects in the classification maps, the results of revealing the changes in the environment, including determining the amount of increase in constructions, changes in the area of soil and vegetation It is obtained.

The produced change map and statistical analysis of the post-classification change detection results reveals that the soil object class is decreased for about 17% and built up areas are increased for about 184% in the 17 years’ time interval. Agricultural fields in this study area are mostly destructed due to the developments in constructing built up areas. The increasing amount of about 104% in vegetation covers relates to the trees and grasslands in new constructed built up areas. To evaluate the obtained results of changes detection in this research, the evaluation of classification maps was used. In this regard, the values of the overall accuracy and Kappa coefficient of the land cover/use classification map in 2002 were 98.41% and 0.86, respectively, and for 2019, 97.01% and 0.87, respectively. Using the capabilities of the object-based analysis method in this research, along with the 15-meter spatial accuracy of the Landsat images, made the classification maps have an acceptable accuracy.

Due to the fact that construction is associated with changing the ecosystem, the construction of housing units in Mehr Pardis has led to the destruction of the mountain environment in some areas and the loss of vegetation in other areas. It is illustrated in the produced land use/ cover change map between 2002 and 2019 that the constructions are rapidly increased in Pardis area and this causes the serious impacts on the environment.