The case of Mrk 370 We are still analysing these data and the only galaxy studied in detail at the moment is Mrk 370.  This slide shows continuum and Halpha maps recovered from our 3D data in comparison with broad band and narrow Halpha image of the galaxy. As it is already known for a long time, it is not easy to substract the continuum from narrow band images because of problems with stellar absorptions. But for 3D it is easier to fit the lins and separate the contribution from emission and absorption. We have also obtained ionisation and extinction maps. We have seen that the extiction is not constant (as we normally assume when working with long-slit data). In this case, we have found a 2 magnitudes of difference between knots and inter-knot region.