We advertise some functional capabilities of our computer large–database management system designed for simulation of gas–analysis procedure and for optimization of search for informative sections in the IR absorption spectra aiming at sounding of atmospheric gases and impurities. One of the computer versions was called GRASSP (Graphics System of Spectra). Its main application is the on–line display of spectroscopic data on the propagation of laser radiation through the atmosphere under various conditions or through model gas mixtures. Recommendations obtained on the basis of the graphs displayed by the system can be used for expert estimate of the efficiency of application of a spectrometric instrument under various atmospheric conditions or in technological cases.