  Analytical expressions for covariances of weak lensing statistics related to
the aperture mass $\Map$ are derived for realistic survey geometries such as
SNAP for a range of smoothing angles and redshift bins. We incorporate the
contributions to the noise due to the intrinsic ellipticity distribution and
the effects of finite size of the catalogue. Extending previous results to the
most general case where the overlap of source populations is included in a
complete analysis of error estimates, we study how various angular scales in
various redshifts are correlated and how the estimation scatter changes with
survey parameters. Dependence on cosmological parameters and source redshift
distributions are studied in detail. Numerical simulations are used to test the
validity of various ingredients to our calculations. Correlation coefficients
are defined in a way that makes them practically independent of cosmology. They
can provide important tools to cross-correlate one or more different surveys,
as well as various redshift bins within the same survey or various angular
scales from same or different surveys. Dependence of these coefficients on
various models of underlying mass correlation hierarchy is also studied.
Generalisations of these coefficients at the level of three-point statistics
have the potential to probe the complete shape dependence of the underlying
bi-spectrum of the matter distribution. A complete error analysis incorporating
all sources of errors suggest encouraging results for studies using future
space based weak lensing surveys such as SNAP.
