WARP(1)

📦
version 0.24 · 5 versions
, in epel 10, epel 9, nixos 26.05, nixpkgs unstable, ubuntu resolute, ubuntu stonking

✨ WARP(1) ✨

okay bestie, welcome to the User Commands section, this is WARP(1) and she is ICONIC 🎀

🌸 NAME 🌸

Warp — warp (transform) input dataset 💫

🦋 SYNOPSIS 🦋

astwarp [OPTION...] ASTRdata

💖 DESCRIPTION 💖

Warp is part of GNU Astronomy Utilities 0.24, and her whole thing is resampling the pixel grid of an input image. Like, she takes your pixels and she re-places them. 💅

By default — meaning if you don't ask for any special linear warping — she'll align the image to the WCS coordinates and remove any possible distortion. That's just the vibe she wakes up in. Linear warping (think --rotate or --scale) has to be explicitly requested with the options under the "Linear warps" group down below, no cap. 🫶

Want more info? Run any of these, and bestie, the second one is the whole entire lore — expected input(s), output(s), and a full description of all the options:

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

And if the manual still left you in the group chat with no reply 😭 you can get direct help from experienced Gnuastro users and developers. For more information, run:

$ info help-gnuastro

🎀 OPTIONS 🎀

Warp options, let's get into it:

🌈 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. tell her where the data lives 💅

🍓 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)

bestie these do NOT happen on their own, you have to actually ask for them, fr fr
  • --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 optional for any corresponding short options. like, the vibes transfer, iykyk. 💜

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

💀 REPORTING BUGS 💀

Found a bug? Not her fault but she wants to know 😭 Report bugs to bug-gnuastro@gnu.org.

Copyright © 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. ✨

okay that's the whole page bestie, go warp something gorgeous 💅 GNU Astronomy Utilities 0.24, November 2025 — mwah, slay, periodt 🎀💖🦋

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