  We have determined new statistical relations to estimate the fundamental
atmospheric parameters of effective temperature and surface gravity, using MK
spectral classification, and vice versa. The relations were constructed based
on the published calibration tables (for main sequence stars) and observational
data from stellar spectral atlases (for giants and supergiants). These new
relations were applied to field giants with known atmospheric parameters, and
the results of the comparison of our estimations with available spectral
classification had been quite satisfactory.
