Satellite predictions and acoustic measurements are often considered to be competing methodes to detect seafloor topography. In opposition to that the supplementing aspects will be pointed out to aim at geophysical interpretations. Advantages and limits of the indirect methode will be briefly explaint starting with the correlation of sea surface heights and sea floor topography. In the next step the deviation of gravity will explained followed by the forward modelling methodes. Finally, differences are shown in the comparision of predicted and measured bathymetry of the Eltanin Impact Area as well as in the comparision of predicted gravity and measured bathymetry of the Weddell Sea.