statistic
Return image plane map statistics.
EXAMPLE
-------

 0>print imstat(rms), imstat(mean), imstat(noise)
 0.237115 0.00853315 0.0056867 
 0>
 0>print imstat(bmin),imstat(bmaj),imstat(bpa)
 2.62014 20.9194 -10.0713 
 0>

PARAMETERS
----------

statistic  -  The name of the statistic wanted. Recognised names are:

               rms   -   The RMS flux density in the map (Jy/beam).
               mean  -   The mean flux density in the map (Jy/beam).
               noise -   The noise level in the map estimated from the
                         visibility and gridding weights. (Jy/beam).
                         Note that this number is meaningless unless
                         the visibility weights are the reciprocal of
                         the amplitude variance. See help wtscale for
                         details.
               bmin  -   The minor axis FWHM of the beam size
                         estimated from the data during the last
                         invert (map units, see help mapunits).
               bmaj  -   The major axis FWHM of the beam size
                         estimated from the data during the last
                         invert (map units, see help mapunits).
               bpa   -   The position angle of the beam major axis,
                         estimated from the data during the last
                         invert (degrees North -> East).

CONTEXT
-------
This function provides access to statistics relating to the latest
map. The return value may be used in expressions, and may thus be used
in automatic mapping procedures.

SIDE EFFECTS
------------
The map will be re-inverted if not currently up to date.

RELATED COMMANDS
----------------
uvstat   - Return UV plane visibility statistics.
peak     - Return details of the min,max or absolute max flux in a map.
mapvalue - Return the value of the map pixel nearest to a given coordinate.
