The oxygen abundance in the IFU era

Spatially-resolved information of gas-phase emission provided by integral field units (IFUs) are allowing us to perform a new generation of emission-line surveys, based on large sam-ples of H ii regions and full two-dimensional coverage. Here we present two highlights of our current studies employing this technique: 1) A statistical approach to the abundance gradients of spiral galaxies, which indicates an universal radial gradient for oxygen abun-dance; and 2) The discovery of a new scaling relation of H ii regions in spiral galaxies, the local mass-metallicity relation of star-forming galaxies.