**3.6 Zonal statistics**

Zonal statistics of segments were computed from NDVI raster layer. In specific, min, max, standard deviation and mean statistics were calculated over each segment. Following, they were exported in a vector layer (shapefile). It was ascertained that mean value statistic comprise an ideal indicator to identify mine areas. Mean value of NDVI for each segment is presented in **Figure 5** superimposed on the natural color image of the study area.
