  In this paper we study a quintessence cosmological model in which the dark
energy component is considered to be the Generalized Chaplygin Gas and the
curvature of the three-geometry is taken into account. Two parameters
characterize this sort of fluid, the $\nu$ and the $\alpha$ parameters. We use
different astronomical data for restricting these parameters. It is shown that
the constraint $\nu \lesssim \alpha$ agrees enough well with the astronomical
observations.
