NAME

mShrinkCube - Reduce the size of a FITS cube

SYNOPSIS

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

DESCRIPTION

A utility for reducing the size of a FITS cube, by averaging blocks of pixels by any factor spatially and by integer factors in the third dimension.

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).

-h hdu

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

-m factor

The (positive integer) factor by which to compress the cube in the third (usually wavelength-related) dimension.

-s statusfile

Output and errors are sent to statusfile instead of to stdout

ARGUMENTS

in.fits

Input FITS cube

out.fits

Path to output FITS cube.

factor

Size of blocks, in (fractional) 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

HDU value (n) must be a non-negative integer

ERROR

Third axis compression factor (n) must be a positive integer

ERROR

Image file in.fits missing of invalid FITS.

ERROR

FITS library error

EXAMPLES

$ mShrinkCube 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.