v.lrs.segment(1)

💖 v.lrs.segment 💖

okay bestie, welcome to the GRASS GIS User's Manual page for v.lrs.segment — she's a lil vector module and she's about to make ur LRS dreams come true ✨

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🌸 NAME 🌸

v.lrs.segment — creates points/segments from input lines, linear reference system and positions read from stdin or a file. no cap, that's literally her whole job 💅

🎀 KEYWORDS 🎀

vector, linear reference system, network — the holy trinity 🫶

✨ SYNOPSIS ✨

v.lrs.segment
v.lrs.segment --help
v.lrs.segment input=name output=name  [llayer=string]
[rsdriver=string]   [rsdatabase=string]  rstable=string  [file=name]
[--overwrite]  [--help]  [--verbose]  [--quiet]  [--ui]

🦋 Flags:

• --overwrite — allow output files to overwrite existing files. yes she will absolutely body ur old file if u let her 😭
• --help — print usage summary. ur bestie explaining herself 📖
• --verbose — verbose module output. she will NOT stop talking and honestly? we love that 🌈
• --quiet — quiet module output. the opposite of the above, main character goes silent 💀
• --ui — force launching GUI dialog. for when u want buttons instead of typing 🎀

🌸 Parameters:

• input=name [required] — name of input vector map. it's the input vector map containing lines, so like, the raw material bestie 🧚
• output=name [required] — output vector map where segments will be written. this is where the magic lands ✨
• llayer=string — layer number or name. this one is the line layer. default is 1 👑
• rsdriver=string — driver name for reference system table. options are: dbf, mesql, mysql, odbc, ogr, pg, sqlite. default is sqlite 💅
• rsdatabase=string — database name for reference system table. default is $GISDBASE/$LOCATION_NAME/$MAPSET/sqlite/sqlite.db — yes the whole thing, don't @ me 🍓
• rstable=string [required] — name of the reference system table. required required, no skips 🙈
• file=name — name of file containing segment rules. if u don't give her one, she reads from stdin. she's flexible like that 💜

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💅 DESCRIPTION 💅

v.lrs.segment creates points/segments from input lines, linear reference system and positions read from standard in or a file. same energy as the NAME section, just saying it again louder 📣

the format is as follows, and pls pls pls respect the format bestie:

P <point_id> <line_id> <milepost>+<offset> [<side offset>]
L <segment_id> <line_id> <milepost>+<offset> <milepost>+<offset> [<side offset>]

🔥 NOTES 🔥

for more info and examples, go look at the help page for v.lrs.segment's sister module, v.segment. sisters supporting sisters fr fr 👑

🌈 EXAMPLE 🌈

this example is written for the Spearfish dataset (it continues the example from v.lrs.create). yes it's a whole cinematic universe, we're doing lore now 🎬

in this example, the 'route_lrs' shall be extended for a new position (point) along the LRS after bus stop 4:

# new point on LRS
echo "P 7 22 4+180" | v.lrs.segment route_lrs out=route_lrs_new rstable=route_lrs
g.region vector=route_lrs n=n+100 s=s-100 -p
d.erase
# existing LRS
d.vect route_lrs
d.vect busstops disp=attr attr=cat size=10 bg=white lcol=blue yref=bottom
d.vect busstops icon=basic/circle fcol=blue
db.select table=route_lrs
# show modified map
d.vect route_lrs_new col=red

slay, look at that display 🫶

🙈 TODO 🙈

figure out how to merge result into existing LRS map and table. it's giving "we'll get to it", iconic honestly 😭

⭐ SEE ALSO ⭐

v.lrs.create, v.lrs.where, v.lrs.label, v.segment

LRS tutorial, Introducing the Linear Reference System in GRASS

go read them, they're the extended universe 🦋

👑 AUTHOR 👑

Radim Blazek

💖 SOURCE CODE 💖

available at: v.lrs.segment source code (history)

accessed: Saturday Jan 17 05:41:24 2026

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© 2003-2025 GRASS Development Team, GRASS GIS 8.4.2 Reference Manual

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and that's the whole page bestie!! this is v.lrs.segment from the GRASS 8.4.2 manual, accessed Saturday Jan 17 05:41:24 2026, © 2003-2025 GRASS Development Team, GRASS GIS 8.4.2 Reference Manual. mwah, go make some segments 💜✨