                                                                reduce_res

Chapter 11 Raster Manipulation
*
The reduce_res command allows a raster to be reduced in size by any positive
whole number factor.  The reduction is done by combining a square block of
pixels on the original raster into a single pixel which represents a larger
area on the final raster.  The user can specify a threshhold.  The threshhold
indicates how many original pixels (in one square block) must be on for the
single final pixel, which represents that block, to be on.  Note that all
vector data IS ALSO RECUCED & IMMEDIATELY AVAILABLE.  This command is meant 
to be used just after importing scanned data, or (on high-resolution contour 
scans) immediately after befor attributing.  The purpose of this command is 
to compensate for scanners which have a fixed resolution, or to scan and 
assemble at high resolution (to maintain line separation) & attribute at 
lower resolution (for faster attributing & smaller file size).
*
NOTE:  If a b-raster (original scan) is present, it too will be reduced in
resolution by the same factor as the editable raster.
*

reduce_res

    Reduces the resolution of the active raster.

         reduce_res n [t]

    Reduces the resolution of the raster by a factor of n.  If specified, the
    optional parameter t will be used as the threshhold; if not specified, t
    is assumed to be (n*n)*0.40.
    ___________________________________________________________________________
    Options/arguments:

         n         Reduction factor; any whole number >1
         t         Threshhold; any whole number between 1 and n*n
    ___________________________________________________________________________
    Example(s):

    To reduce the current map's raster by a factor of 4 with a threshhold of
    12, enter:
     
         reduce_res 4 12
    ___________________________________________________________________________
    See also:

              negative_img, reflect, rotate
    ___________________________________________________________________________
