Abstract: Analysis of plasma data indicative of gaseous species therein, such as Optical Emission Spectroscopy (OES) data, is aided through the interactive use of a computer. OES data may be calibrated by the computer with minimal input from the user regarding a gas the user knows or suspects is present. The computer then assumes the presence of that gas and assigns relative intensity peaks to known wavelengths for that gas, allowing calibration to take place. Selective identification of particular gases from the data is also possible. Used in conjunction with selective identification, a learning function allows the system to improve the accuracy of future gaseous species identification. Certain characteristics of a particular gas over time, such as intensity at a particular wavelength or at all wavelengths, may also be automatically plotted.