  We present colour transformations for the conversion of the {\em 2MASS}
photometric system to the Johnson-Cousins $UBVRI$ system and further into the
{\em SDSS} $ugriz$ system. We have taken {\em SDSS} $gri$ magnitudes of stars
measured with the 2.5-m telescope from $SDSS$ Data Release 5 (DR5), and $BVRI$
and $JHK_{s}$ magnitudes from Stetson's catalogue and \citet{Cu03},
respectively. We matched thousands of stars in the three photometric systems by
their coordinates and obtained a homogeneous sample of 825 stars by the
following constraints, which are not used in previous transformations: 1) the
data are de-reddened, 2) giants are omitted, and 3) the sample stars selected
are of the highest quality. We give metallicity, population type, and
transformations dependent on two colours. The transformations provide absolute
magnitude and distance determinations which can be used in space density
evaluations at short distances where some or all of the {\em SDSS} $ugriz$
magnitudes are saturated. The combination of these densities with those
evaluated at larger distances using {\em SDSS} $ugriz$ photometry will supply
accurate Galactic model parameters, particularly the local space densities for
each population.
