Fig. 3
From: Identification of subsurface cavities in urban environment
(a) The altitudes map and (b) the Bouguer anomaly (BA) map of the M’Rara area. The data were uniformly reduced using a Bouguer correction density of 2400 kg/m3. The displayed projection system is geographic (East longitude and North latitude) and Cartesian coordinates (WGS84, UTM zone 31 N in meters).
