  Model stellar atmospheres are fundamental tools for understanding stellar
observations from interferometry, microlensing, eclipsing binaries and
planetary transits. However, the calculations also include assumptions, such as
the geometry of the model. We use intensity profiles computed for both
plane-parallel and spherically symmetric model atmospheres to determine fitting
coefficients in the BVRIHK, CoRot and Kepler wavebands for limb darkening using
several different fitting laws, for gravity-darkening and for interferometric
angular diameter corrections. Comparing predicted variables for each geometry,
we find that the spherically symmetric model geometry leads to different
predictions for surface gravities log g < 3. In particular, the most commonly
used limb-darkening laws produce poor fits to the intensity profiles of
spherically symmetric model atmospheres, which indicates the need for more
sophisticated laws. Angular diameter corrections for spherically symmetric
models range from 0.67 to 1, compared to the much smaller range from 0.95 to 1
for plane-parallel models.
