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MATERIALS AND METHODOLOGY
MATERIJALI I METODE
Study Area – Područje istraživanja
The cadastral municipality of Brezici is located in the southeastern part of the city of Derventa, Figure 1. Various land uses are present in the cadastral municipality of Brezici, and according to data from the cadastre, the largest area is occupied by agricultural fields, followed by forests, meadows, grassland, and orchards. According to data from the Real Estate Cadastre Database, the most represented type of forest is the deciduous forest, covering 185 ha, which is 26% of the total territory. The survey in the city of Derventa was conducted between 1976 - 1977 (RUGIPP 2016).
Input Data – Ulazni podaci
Compared to the popular Landsat 8 and other non-commercial satellites, the Sentinel-2 satellites provide more detail in the NIR and SWIR bands, which contributes to the performance of land cover classification for monitoring urban environments, forests, smart agriculture, and many others (ED Chaves et al. 2020).
Sentinel-2 data is available in different processed forms because Sentinel-2 MSI products undergo different stages of processing to reach a level that can be accessed by the users (Phiri et al. 2020): Level – 0, Level – 1A, Level – 1B, Level – 1C and Level – 2A. Level-0 and Level-1A are not accessible to the users, whereas Level-1C (TOA) and Level-2A (BOA) are used for mapping land cover and land use, respectively. The original data for the cadastral municipality of Brezici were taken from the Real Estate Cadastre Database.
Methods – Metode
The idea of this study is to show the changes that take place in a small, limited area over appropriate periods, with an emphasis on the emergence of new forest areas and the abandonment of agricultural areas due to accelerated urbanization, which is particularly visible in the areas of former socialist countries. The extended steps of the study are shown in Figure 2. The first step includes downloading Sentinel-2 images for two time periods, 2017 and 2022.
Images were classified in both time series in the same way (described in the next chapter) and the accuracy of both classified images was assessed. Along with the performed classification, as well as for its needs, the NDVI (Normalized Difference Vegetation Index) index was calculated. The classification was performed using the RF algorithm. In addition to Sentinel-2 images, the data from the Real Estate Cadastre Database for a specific cadastral municipality were also used. The downloaded data were classified and converted into raster data to compare them.
Download and processing of Sentinel-2 data – Preuzimanje i obrada Sentinel-2 snimki
For this study, Sentinel – 2 (Level - 2A) data were downloaded from the Copernicus Sci Hub platform. The images were downloaded for two-time epochs in August and November 2017, and in May and September 2022, and sorted by spectral channels. We used B2-Blue, B3-Green, B4-Red, B8-NIR (Near-InfraRed) and B6-Red edge, B7-Red edge, B8A-Narrow NIR, B11-SWIR (Short-Wave InfraRed), B12-SWIR in further procedures and analyses. The criterion for