  We present accurate and deep multi-band ($g,r,i$) photometry of the Local
Group dwarf irregular galaxy NGC 6822. The images were collected with wide
field cameras at 2m/4m- (INT,CTIO,CFHT) and 8m-class telescopes (SUBARU)
covering a 2 square degrees FoV across the center of the galaxy. We performed
PSF photometry of $\approx$7,000 CCD images and the final catalog includes more
than 1 million objects. We developed a new approach to identify candidate field
and galaxy stars, and performed a new estimate of the galaxy center by using
old stellar tracers finding that it differs by 1.15 (RA) and 1.53 (DEC) arcmin
from previous estimates. We also found that young (Main Sequence, Red
Supergiants), intermediate (Red Clump, Asymptotic Giant Branch [AGB]) and old
(Red Giant Branch [RGB]) stars display different radial distributions. Old
stellar population is spherically distributed and extends to radial distances
larger than previously estimated ($\sim$1 degree). The young population shows a
well defined bar and a disk-like distribution, as suggested by radio
measurements, that is off-center compared with old population. We discuss pros
and cons of the different diagnostics adopted to identify AGB stars and develop
new ones based on optical-NIR-MIR color-color diagrams (CCDs) to characterize
Oxygen and Carbon (C) rich stars. We found a mean population ratio between
Carbon and M-type (C/M) stars of 0.67$\pm$0.08 (optical/NIR/MIR) and we used
the observed C/M ratio with empirical C/M-metallicity relations to estimate a
mean iron abundance of [Fe/H]$\sim$-1.25 ($\sigma$=0.04 dex) that agrees quite
well with literature estimates.
