The connection between the small-scale structure of the HII regions and their integrated spectrum is largely unknown and the main source of uncertainty in the determination of chemical abundances. We propose a project that attempts to alleviate this situation by obtaining and studying, for the first time, integral field spectra of an extensive sample of nearby HII regions, of the Milky Way and the Magellanic Clouds combining two complementary points of view: (a) the analysis of the spatial distribution of the physical conditions and chemical abundances in the nebula at small angular scales and their correlation with internal structures and (b) the determination of global magnitudes of the nebulae from the integrated spectrum. The results of this study will allow to restrict the spatial variations of the electron temperature and density in the nebulae and explore their impact on global temperature and chemical abundances. Maps of the distribution of the temperature fluctuations parameter and the abundances discrepancy will also be obtained to quantify the average value of both quantities and explore their possible correlation. Other essential parameters that are largely unknown in HII regions will also be estimated, such as the number of ionizing photons, the global ionization parameter or the filling factor. The availability of integrated spectra of local HII regions will be essential for a more appropriate comparison with the results of photoionization models. This is crucial a aspect to obtain a more accurate estimate of the ionization correction factors necessary to determine total abundances. Finally, with the proposed database, we can have a sample of local HII regions with different physical properties, metallicities and well-known internal structures that we can use to better determine the chemical composition of the most distant extragalactic HII regions. In addition, this will allow to re-calibrate the strongline methods for metallicity estimation.