Supplementary material of: "A spectra classification methodology of hyperspectral infrared images for near real-time estimation of the SO2 emission flux from Mount Etna with LARA radiative transfer retrieval model" Data from IMAGETNA campaign (September 2015 - Image size: 320 x 64 pixels - Pixel size: 2.8 x 2.8 m) 23/06/2015 - 08:12:45-08:22:22 (UTC)