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WARP(1) 			  User Commands 			 WARP(1)

NAME
     Warp - warp (transform) input dataset

SYNOPSIS
     astwarp [OPTION...] ASTRdata

DESCRIPTION
     Warp is part of GNU Astronomy Utilities 0.24.  Warp will resample the pixel
     grid  of  an  input  image. By default (if no special linear warping is re-
     quested), it will align the image to the WCS coordinates in  anyand  remove
     any  possible  distortion.  Linear  warping  (like '--rotate' or '--scale')
     should be explicitly requested with the options under  the  "Linear  warps"
     group below.

     For more information, please run any of the following commands. In particu-
     lar  the second contains a very comprehensive explanation of Warp's invoca-
     tion: expected input(s), output(s), and a full description of all	the  op-
     tions.

     All options and their values:
	    $ astwarp -P

     Inputs/Outputs and options:
	    $ info astwarp

     Full section in manual/book:
	    $ info Warp

     Full Gnuastro manual/book:
	    $ info gnuastro

     If  you  couldn't	find  your answer in the manual, you can get direct help
     from experienced Gnuastro	users  and  developers.  For  more  information,
     please run:

	    $ info help-gnuastro

     Warp options:

	    Input:

     --hendwcs=INT
	    Header keyword number to end reading WCS.

     --hstartwcs=INT
	    Header keyword number to start reading WCS.

     -h, --hdu=STR/INT
	    Extension name or number of input data.

	    Output:

     -C, --coveredfrac=FLT
	    Acceptable fraction of output pixel covered.

     -D, --dontdelete
	    Don't delete output if it exists.

     -k, --keepwcs
	    Do not apply warp to input's WCS

     -K, --keepinputdir
	    Keep input directory for automatic output.

     --outfitsnocommit
	    No Git commit in 0-th HDU of output FITS.

     --outfitsnoconfig
	    No metadata in 0-th HDU of output FITS.

     --outfitsnodate
	    No 'DATE' in 0-th HDU of output FITS.

     --outfitsnoversions
	    No versions in 0-th HDU of output FITS.

     -o, --output=STR
	    Output file name.

     -T, --type=STR
	    Type of output: e.g., int16, float32, etc...

     --wcslinearmatrix=STR
	    WCS linear matrix of output ('pc' or 'cd').

	    Align with WCS coordinates (correcting distortion, default mode)

     --checkmaxfrac
	    Moire pattern: Max.frac. input pixels on output.

     --ctype=STR[,STR]
	    FITS standard CTYPE value (e.g., 'RA---TAN').

     -c, --center=FLT,FLT
	    Center coordinate of the output image in RA,DEC.

     --edgesampling=INT
	    Number of extra samplings in pixel sides.

     -G, --gridfile=FITS
	    File to use for output grid.

     -H, --gridhdu=STR
	    HDU/extension to use for output grid.

     --widthinpix	    --width is in pixels, not in WCS coordinates.

     -w, --width=INT,INT
	    Output image size in both dimensions.

     -x, --cdelt=FLT[,FLT]
	    Pixel scale of output (usually degrees/pixel).

	    Linear warps (must be called explicitly on command-line)

     --centeroncorner
	    Center of coordinates on first pixel corner.

     -e, --shear=FLT[,FLT]
	    Shear along the given axis(es).

     -f, --flip=INT[,INT]
	    Flip along the given axis(es).

     -m, --matrix=STR
	    Raw transformation matrix, highest priority.

     -p, --project=FLT[,FLT]
	    Project along the given axis(es).

     -r, --rotate=FLT
	    Rotate by the given angle in degrees.

     -s, --scale=FLT[,FLT]
	    Scale along the given axis(es).

     -t, --translate=FLT[,FLT]
	    Translate along the given axis(es).

	    Operating modes:

     -?, --help
	    give this help list

     --checkconfig
	    List all config files and variables read.

     --cite
	    BibTeX citation for this program.

     --config=STR
	    Read configuration file STR immediately.

     --config-prefix=STR
	    Custom prefix of option names config files.

     --lastconfig
	    Do not parse any more configuration files.

     --log  Information about output(s) in a log file.

     --minmapsize=INT
	    Min. bytes to avoid RAM automatically.

     -N, --numthreads=INT
	    Number of CPU threads to use.

     --onlyversion=STR
	    Only run if the program version is STR.

     -P, --printparams
	    Print parameter values to be used and abort.

     --quietmmap
	    Don't print mmap'd file's name and size.

     -q, --quiet
	    Only report errors, remain quiet about steps.

     -S, --setdirconf
	    Set default values for this directory and abort.

     --usage
	    give a short usage message

     -U, --setusrconf
	    Set default values for this user and abort.

     -V, --version
	    print program version

     Mandatory	or  optional arguments to long options are also mandatory or op-
     tional for any corresponding short options.

     GNU Astronomy Utilities home page: http://www.gnu.org/software/gnuastro/

REPORTING BUGS
     Report bugs to bug-gnuastro@gnu.org.

COPYRIGHT
     Copyright (C) 2015-2025 Free Software Foundation, Inc.  License GPLv3+: GNU
     General public license version 3 or later.
     This is free software: you are free to change and redistribute  it.   There
     is NO WARRANTY, to the extent permitted by law.

     Written/developed by Mohammad Akhlaghi and Pedram Ashofteh-Ardakani

SEE ALSO
     The  full documentation for Warp is maintained as a Texinfo manual.  If the
     info and Warp programs are properly installed at your site, the command

	    info Warp

     should give you access to the complete manual.

GNU Astronomy Utilities 0.24	  November 2025 			 WARP(1)

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