Geomatics is an amalgam of methods, algorithms and practices in handling data referred to the Earth by informatic tools. This book is an attempt to identify and rationally organize the statistical-mathematical methods which are common in many fields where geomatics is applied, like geodesy, geophysics and, in particular, the field of inverse problems and image analysis as it enters into photogrammetry and remote sensing. These lecture notes aim at creating a bridge between people working in different disciplines and making them aware of a common methodological basis.