  Our detailed analytic local disc model (JJ-model) quantifies the
interrelation between kinematic properties (e.g. velocity dispersions and
asymmetric drift), spatial parameters (scale-lengths and vertical density
profiles), and properties of stellar sub-populations (age and abundance
distributions). Any consistent radial extension of the disc evolution model
should predict specific features in the different distribution functions and in
their correlations. Large spectroscopic surveys (SEGUE, RAVE, APOGEE, Gaia-ESO)
allow significant constraints on the long-term evolution of the thin disc. We
discuss the qualitative difference of correlations (like the alpha-enhancement
as function of metallicity) and distribution functions (e.g. in [Mg/H] or
[Fe/H]) for the construction of a disc model. In the framework of the JJ-model
we build a local chemical enrichment model and show that significant vertical
gradients for main sequence and red clump stars are expected in the thin disc.
A Jeans analysis of the asymmetric drift provides a link to the radial
structure of the disc. The derived metallicity-dependent radial scale-lengths
can be combined in the future with the abundance distributions at different
Galactocentric distances to construct full disc models. We expect to be able to
constrain possible scenarios of inside-out growth of the thin disc and to
characterise those populations, which require significant radial migration.
