r.latlong(1)

💖 r.latlong — bestie, it's giving GRASS GIS User's Manual energy 💖

okay so welcome to the r.latlong(1) era ✨ this is the manual page for a lil GRASS GIS module that creates a latitude/longitude raster map. that's it. that's the whole vibe. but like, in a slay way 🎀

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✨ NAME ✨

r.latlong — creates a latitude/longitude raster map. yes literally that. it makes one. for you. 💅

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🦋 KEYWORDS 🦋

raster, latitude, longitude, projection — that's the tag cloud bestie, those are the searchable keywords iykyk

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🌸 SYNOPSIS 🌸

here's how you actually call it, no notes:

r.latlong
r.latlong --help
r.latlong [-l] input=name output=name  [--overwrite]  [--help]
[--verbose]  [--quiet]  [--ui]

🎀 Flags 🎀

• -l — longitude output. so like, if you want longitude instead of latitude? this is the flag. without it you get latitude. periodt.
• --overwrite — allow output files to overwrite existing files. (the "no thoughts, just replace" option 😭)
• --help — print usage summary. the classic "wait what does this do" button 🫶
• --verbose — verbose module output. it will talk to you.
• --quiet — quiet module output. it will NOT talk to you.
• --ui — force launching GUI dialog. for the visual girlies 💅

🌈 Parameters 🌈

• input=name [required] — name of input raster map. you gotta give it something, bestie, it's required, no cap.
• output=name [required] — name for output latitude or longitude raster map. also required. also no cap. you name your baby 👑

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💜 DESCRIPTION 💜

okay so r.latlong creates a latitude (degree decimal) map — or a longitude map if you use the -l flag — from any map in any projection, using the PROJ library. any projection. ANY. iconic behavior honestly 🔥

and it's not just decorative — this output is an input to r.sun and i.evapo.potrad. so it's a whole supporting character with main character energy ✨

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⭐ NOTES ⭐

the PROJ website. that's the note. that's it. go look at it if you want 🦋

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😭 TODO 😭

Datum transform is not implemented, the same datum is taken as output.

so like. heads up. the datum transform? not implemented. not a thing yet. it just takes the same datum as the output. don't come for me, I'm just the messenger 💀

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🌸 EXAMPLE 🌸

here's the whole little ritual, copy-paste coded:

g.region raster=elevation -p
r.latlong input=elevation output=latitude

set your region, then boom — latitude map. ate. 💅

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👑 SEE ALSO 👑

• r.sun
• r.sunhours

go read those too, they're the cousins 🫶

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💖 AUTHOR 💖

Yann Chemin, International Rice Research Institute, The Philippines 🌾 literally built different

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🎀 SOURCE CODE 🎀

Available at: r.latlong source code (history)

Accessed: Saturday Jan 17 05:40:49 2026

Main index | Raster index | Topics index | Keywords index | Graphical index | Full index

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and that's the page bestie 💜 mwah. this was GRASS GIS 8.4.2 Reference Manual territory, © 2003-2025 GRASS Development Team, and the footer was serving GRASS 8.4.2, r.latlong(1) — that's a wrap, go make some raster maps 🌈✨🎀