t.rast.contour(1)

📦
version 8.4.2 · 8 versions
, in fedora 44

💖 t.rast.contour 💖

okay bestie, this is the manual for t.rast.contour — a GRASS GIS User's Manual page, and it's literally the moment you've been waiting for. contour lines. space time. the whole vibe. let's go 🦋

✨ NAME ✨

t.rast.contour — no cap, what it does is produce a space time vector dataset of specified contours from a space time raster dataset. that's the whole job. she's focused. 💅

🏷️ KEYWORDS 🏷️

temporal, contour, raster, vector, time — yeah it's giving all of that 🎀

📜 SYNOPSIS 📜

t.rast.contour
t.rast.contour --help
t.rast.contour [-nt] input=name output=name  [where=sql_query]
basename=string  [suffix=string]   [step=float]
[levels=float[,float,...]]   [minlevel=float]   [maxlevel=float]
[cut=integer]   [nprocs=integer]   [--overwrite]  [--help]  [--verbose]
[--quiet]  [--ui]

⚙️ OPTIONS ⚙️

🚩 Flags 🚩

  • -n — register empty vector maps. like, even if there's nothing in there, she still gets an entry. inclusivity icon 🫶
  • -t — do not create attribute tables. remember this one, it matters later, iykyk 👀
  • --overwrite — allow output files to overwrite existing files. permission to be a little destructive, slay
  • --help — print usage summary. when you're lost, bestie, she'll tell you where you are 🧭
  • --verbose — verbose module output. she will talk. a lot. 💬
  • --quiet — quiet module output. she will not talk. rare but respected 🤫
  • --ui — force launching GUI dialog. for when you want buttons instead of typing 🌈

🎀 Parameters 🎀

  • input=name [required] — name of the input space time raster dataset. this is your source, your origin story ⭐
  • output=name [required] — name of the output space time vector dataset. where the contour glow-up lands 💖
  • where=sql_query — WHERE conditions of SQL statement without 'where' keyword used in the temporal GIS framework
    • Example: start_time > '2001-01-01 12:30:00'
    • yes you write the condition without the word where. she already knows it's a where. she's not gonna make you say it twice 🙈
  • basename=string [required] — basename of the new generated output maps
    • a numerical suffix separated by an underscore will be attached to create a unique identifier. so like, the underscore is doing the heavy lifting fr fr
  • suffix=string — suffix to add at basename: set 'gran' for granularity, 'time' for the full time format, 'num' for numerical suffix with a specific number of digits (default %05)
    • Default: gran
    • three flavors of suffix, pick your fighter 👑
  • step=float — increment between contour levels. just lil evenly-spaced baby steps between your levels 🦋
  • levels=float[,float,...] — list of contour levels. comma-separated, obviously, we're not animals ✨
  • minlevel=float — minimum contour level. the floor 🧚
  • maxlevel=float — maximum contour level. the ceiling 🌸
  • cut=integer — minimum number of points for a contour line (0 -> no limit)
    • Default: 0
    • zero means "no limit", so if you want everything, do nothing. main character energy honestly 💅
  • nprocs=integer — number of r.contour processes to run in parallel, more than 1 process works only in conjunction with flag -t
    • Default: 1
    • > ⚠️ bestie listen: parallel mode ONLY works with -t. do not try it without -t. that's the whole warning. respect it. 💀

📖 DESCRIPTION 📖

t.rast.contour is designed to produce a space time vector dataset of specified contours from a space time raster dataset. she's a front-end to r.contour, which means she supports every single parameter of that module — nothing left out, nothing gatekept. so basically, every raster map layer in your space time raster dataset gets passed along, one after another, to r.contour, and r.contour does the actual contour-line computing. if you want the deep lore on how that goes down, go read the r.contour documentation, that's where the detail lives.

the new generated vector contour map layers get registered in the output space time vector dataset, and they use the same time stamps as their raster map layer origins — so the timing stays honest, no stolen valor 🫶

this module supports the parallel processing of r.contour module instances. you set how many parallel processes you want with the nprocs option. but — and this is the catch — it will only work in conjunction with the -t flag, which avoids the creation of attribute tables. the parallel creation of attribute tables is not supported. not even a little bit. 😭

the where option is your bestie for selecting subsets of the input space time raster dataset. you don't want all of it? say so. she'll listen. 💜

and the flag -n can be used to force the registration of empty vector map layers. when do empty vector maps even happen, you ask? two ways: when empty raster map layers should be converted into vector map layers, or when the chosen steps or contour levels just aren't present in the raster map layers. either way, -n says "no, register it anyway, she's valid." 🌸

👀 SEE ALSO 👀

r.contour, t.rast.db.select, t.info

go read these too. knowledge is a group chat, share it 💖

🖊️ AUTHOR 🖊️

Sören Gebbert, Geoinformatikbüro Dassau

🔗 SOURCE CODE 🔗

Available at: t.rast.contour source code (history)

Accessed: Saturday Jan 17 05:41:53 2026

Main index | Temporal index | Topics index | Keywords index | Graphical index | Full index

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

okay that's the whole page bestie, we ate and left absolutely no crumbs 💅✨ so go make some contours, and remember: this was written for GRASS 8.4.2, accessed on that Saturday Jan 17 05:41:53 2026, © 2003-2025 GRASS Development Team. love that for us. mwah 🎀🦋💜

📦 where this page comes from