Ricerc@Sapienza

Landfill monitoring requires knowledge of the landfill body's volumetric characteristics at frequent time intervals. In addition to this three-dimensional information, other information may also be useful, such as surface temperature, which may be influenced by the chemical, physical and geotechnical processes inherent in the development of the landfill itself. On the other hand, the logistical and environmental conditions normally encountered at such sites make it difficult to use traditional geomatic techniques.

The drones allow to acquire geometric and thematic information quickly and with considerable operational advantages in close range surveys. The lower flight altitude, and the possibility of rapidly replacing the sensors between panchromatic, multispectral and thermal sensors allow the detection of useful characteristics for monitoring and control, even periodically, of areas with reduced size.

High-resolution satellite images must undergo a geometric rectification process in order to be used for metrical purposes. This operation, called orthorectification, is necessary because of deformations mainly due to camera distortions and acquisition geometry. To correctly orthorectify an image, it is necessary to accurately reconstruct the photogrammetric-acquisition characteristics and the image position with respect to a reference system connected to the ground.

High and very high resolution satellite images are now an irreplaceable resource for earth observation in general and for the extraction of hydrogeological information in particular. In order to use them correctly and compare them with previous surveys and maps, they must be treated geometrically to removethedistortions introduced by the acquisition process. Orthorectification is not a simple georeferencing because the process must take into account the three-dimensional acquisition geometry of the sensor.