HPXCVT(1)

💫 HPXcvt — HEALPix glow-up edition 💫

okay bestie, so this is HPXcvt from the User Commands era, and it's literally the tool that takes your messy HEALPix data and reorganises it into a 2-D FITS image. Reorganise HEALPix data into a 2-D FITS image. That's the whole vibe. No cap.

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✨ SYNOPSIS ✨

HPXcvt [-C<col>] [-c<sys>] [-n|-r] [-q<quad>] [-x<n|s>]

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🦋 DESCRIPTION 🦋

[<infile> [<outfile>]]

(the file args are hanging out down here in the description, iconic of them, but that's just how this page is laid out 💅)

HPXcvt takes your HEALPix data and reorganises it into a 2-D FITS image using the HPX coordinate system. That's the main character transformation arc fr fr.

Your input data can be living its life in a FITS file as a primary image, or as an image extension, or as a binary table extension — all three are welcome here, no gatekeeping 🫶

And both NESTED and RING pixel indices are supported, so whichever one your data woke up in, you're covered. ✨

About the files: you can straight up omit the input and output files, or you can pass them as - to mean stdin and stdout respectively. Very flexible, very demure.

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🎀 OPTIONS 🎀

• -C<col> — Binary table column number from which to read data. The default is 1. And bestie, n.b.: WMAP exclusion masks are in column 2, so if that's you, you know what to do. 💀
• -c<sys> — Tells it which coordinate system to use when labelling the output map, but only when the COORDSYS keyword is absent from the input FITS header. The recognised values are g (galactic), e (ecliptic) or q (equatorial). Pick your fighter. 🌈
• -n|-r — Assume n(ested) or r(ing) organization if the ORDERING keyword is absent from the input FITS header. It's giving "just tell me which one, I'm not psychic". 🙈
• -q<quad> — Recentre longitude at quad(mod 4) x 90 degrees, where quad(rant) is an integer. Yes, that means the integer gets taken mod 4. Math girlies stay winning. 👑
• -x<n|s> — Use a north-polar or south-polar layout, aka XPH. Pick n or s and go off. 🧚

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💀 quick vibe check: the ordering and coordinate system flags are literally only there for when the FITS header is missing its keywords — if the header already says it, it already says it.

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HPXcvt version 8.9, dated June 2026 — that's the source and the date, and that's the whole page, bestie. Go reorganise something. Slay. 💖✨🎀