Multi baseline interferometric data can be exploited for generating DEM, to estimate volumetric scattering and to get resolution on areas affected by foreshortening and layover. Moreover, multi baseline data allow to increase the elevation ambiguity interval, to detect and reduce atmospheric artifacts and to get high resolution coherence maps (i.e. an ensemble average is used instead of a space average). Results of the improvements achievable from multi baseline ERS-1 and Tandem data will be presented for the area of Bonn (ERS-1 images taken at 3 days interval during March 92) and Naples (4 Tandem pairs on Mt. Vesuvius, 1995-1996, have been used).