1. A method comprising: for at least one source, identifying primary spectral features of source spectroscopic data obtained for at least one source; storing data describing the primary spectral features of the at least one source; first analyzing sample spectroscopic data obtained for a sample with respect to said data describing the primary spectral features of the at least one source to determine whether the sample spectroscopic data contains the primary spectral features for the at least one source; generating a reduced relevant library spectra by eliminating from further consideration a source whose primary spectral features are determined not be present in the sample spectroscopic data; and second analyzing said sample spectroscopic data with respect to the reduced relevant library spectra in order to identify one or more sources present in the sample.