d.geodesic(1grass)

✨ d.geodesic — bestie, let's draw the shortest line on a globe 🌍

okay so this is d.geodesic(1grass), straight out of the GRASS User's Manual, and it's literally the tool for tracing the shortest path between two points on a curved Earth. great circle girlies rise 💅

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🌸 NAME 🌸

d.geodesic — bestie, this one displays a geodesic line, tracing the shortest distance between two geographic points along a great circle, in a longitude/latitude data set. no cap. 🦋

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🎀 KEYWORDS 🎀

display, distance, great circle, shortest path ✨

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💖 SYNOPSIS 💖

d.geodesic
d.geodesic --help
d.geodesic coordinates=lon1,lat1,lon2,lat2  [line_color=name]
[text_color=name]   [units=string]   [--help]  [--verbose]  [--quiet]
[--ui]

🫶 Flags:

• --help — print the usage summary, so you know what's up 📖
• --verbose — verbose module output, she's chatty 💬
• --quiet — quiet module output, she's giving mysterious 🤫
• --ui — force launching GUI dialog, for the visual besties 🖥️

🍓 Parameters:

• coordinates=lon1,lat1,lon2,lat2 [required] — the starting and ending coordinates, and yes she's required, you can't skip her 🙈
• line_color=name — line color. either a standard color name or an R:G:B triplet. default is black 🖤
• text_color=name — text color. either a standard color name or an R:G:B triplet 🎨
• units=string — units. units. (yes she said it twice 😭) options: meters, kilometers, feet, miles default: meters 📏

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💅 DESCRIPTION 💅

okay so d.geodesic displays a geodesic line in the active frame on the user's graphics monitor. this is also known as the great circle line, and she traces the shortest distance between two user-specified points on the curved surface of a longitude/latitude data set. iconic behavior honestly 🌈

the two coordinate locations you name must fall within the boundaries of the user's current geographic region. like, she will not go outside the region, that's the vibe check 🚧

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✨ OPTIONS ✨

by default, black line color and red text color will be used. periodt. 🖤❤️

by indicating the starting and ending coordinates of the geodesic, the line and its length (by default in meters) are displayed to the graphical output. if the text color is set to none, the great circle distance is not displayed. so like, no text, no distance, she goes silent 🤐

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🦋 EXAMPLE 🦋

a geodesic line if shown over the political map of the world (demolocation dataset):

g.region vector=country_boundaries -p
d.mon wx0
d.vect country_boundaries type=area
# show additionally a 20 degree grid
d.grid 20
d.geodesic coordinates=55:58W,33:18S,26:43E,60:37N \
  line_color=yellow text_color=red units=kilometers

Geodesic line (great circle line) 👑

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🌸 NOTES 🌸

this program works only with longitude/latitude coordinate system. that's it, that's the note. don't try her anywhere else, she will not slay 💀

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🌟 SEE ALSO 🌟

d.rhumbline, d.grid, m.measure — go read those too bestie, they're the friend group 🫶

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👑 AUTHOR 👑

Michael Shapiro, U.S. Army Construction Engineering Research Laboratory 🫡

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🧚 SOURCE CODE 🧚

available at: d.geodesic source code (history)

latest change: Thursday May 08 14:17:52 2025 in commit: 3caa352f78f86a51ca463a6f1ba7ffe3db9771df

main index | display index | topics index | keywords index | graphical index | full index

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and that's a wrap, bestie 💖 this was GRASS 8.5.0 (the Reference Manual, © 2003-2026 GRASS Development Team), last touched Thursday May 08 14:17:52 2025, and the page signs off all cute as d.geodesic(1grass) under the GRASS 8.5.0 banner. slay, go draw some great circles 🌍✨🎀