  In this paper, we investigate the properties of the planet-induced deviations
in the trajectory of the microlensed source star centroid motion (astrometric
curve) and the correlations between the astrometric and photometric deviations.
For this, we construct vector field maps of excess centroid shifts. Fromthe
investigation of the maps, we find that the astrometric deviation is closely
correlated with the photometric one. The astrometric deviation increases as the
photometric deviation increases and $\Delta\deltavec$ is directed towards the
planet when the light curve has positive deviation and vice versa. We also
present excess centroid shift maps for lens systems with various values of the
planetary separation, planet/primary mass ratio, and source size to show the
changes in the pattern of excess centroid shifts with these parameters.
