NAME

       mShrink - Re-size a FITS image

SYNOPSIS

       mShrink [-f] [-d level] [-h hdu] [-s statusfile] in.fits out.fits factor

DESCRIPTION

       A utility for reducing the size of a FITS file, by averaging blocks of pixels.

OPTIONS

       -f     Fixed-size  flag  -  specify output size of image, instead of the size of blocks of
              pixels to be averaged

       -d level
              Turns on debugging to the specified level (1-4).

       -s statusfile
              Output and errors are sent to statusfile instead of to stdout

ARGUMENTS

       in.fits
              Input FITS file

       out.fits
              Path to output FITS file.

       -h hdu Use the specified FITS extension (default is to use the first HDU with image data)

       factor Size of blocks, in pixels, to average.  File  size  will  be  reduced  by  1/factor
              squared.  If  the  -f (fixed-size) flag is used, factor is the desired width of the
              output image.

RESULT

       [Normal mode]: FITS output image, reduced in size by a factor of (1/factor)^2  .

       [Fixed-size mode]: FITS output image of width factor

MESSAGES

       OK     [struct stat="OK"]

       ERROR  Cannot open status file: statusfile

       ERROR  Image size factor cannot be interpreted as an real number

       ERROR  Shrink factor factor cannot be interpreted as an real number

       ERROR  [struct stat="ERROR", msg=

       ERROR  Image file in.fits missing of inavlid FITS.

       ERROR  FITS library error

EXAMPLES

       $ mShrink final/out.fits final/out-lowres_5.fits 5
              [struct stat="OK"]

BUGS

       The drizzle algorithm has been implemented but has not been tested in this release.

       If a header template contains  carriage  returns  (i.e.,  created/modified  on  a  Windows
       machine),  the cfitsio library will be unable to read it properly, resulting in the error:
       [struct stat="ERROR", status=207, msg="illegal character in keyword"]

       It is best for the background correction algorithms if the area described  in  the  header
       template  completely encloses all of the input images in their entirety. If parts of input
       images are "chopped off" by  the  header  template,  the  background  correction  will  be
       affected.  We  recommend  you  use  an expanded header for the reprojection and background
       modeling steps, returning to the originally desired header size for the final  coaddition.
       The default background matching assumes that there are no non-linear background variations
       in the individual images (and therefore in the  overlap  differences).  If  there  is  any
       uncertainty  in  this  regard, it is safer to turn on the "level only" background matching
       (the "-l" flag in mBgModel.

COPYRIGHT

       2001-2015 California Institute of Technology, Pasadena, California

       If your research  uses  Montage,  please  include  the  following  acknowledgement:  "This
       research  made use of Montage. It is funded by the National Science Foundation under Grant
       Number ACI-1440620, and was previously  funded  by  the  National  Aeronautics  and  Space
       Administration's  Earth Science Technology Office, Computation Technologies Project, under
       Cooperative Agreement Number  NCC5-626  between  NASA  and  the  California  Institute  of
       Technology."

       The  Montage  distribution  includes an adaptation of the MOPEX algorithm developed at the
       Spitzer Science Center.