v.what.rast3(1)

📦
version 8.4.2 · 8 versions
, in fedora 44

💖 v.what.rast3 💖

okay so bestie, welcome to the GRASS GIS User's Manual page for v.what.rast3 (that's the (1) general commands section, iykyk). she uploads 3D raster values at positions of vector points to the table. yes she's that girl. 🎀

✨ NAME ✨

v.what.rast3 — Uploads 3D raster values at positions of vector points to the table. literally her whole thing. 💅

🌸 KEYWORDS 🌸

vector, sampling, raster, position, querying, attribute table, surface information

🦋 SYNOPSIS 🦋

v.what.rast3
v.what.rast3 --help
v.what.rast3 map=name  [layer=string]  raster_3d=name column=name
[where=sql_query]   [--help]  [--verbose]  [--quiet]  [--ui]

⭐ Flags ⭐

  • --help — prints the usage summary. the classic cry-for-help flag, no shame in it 🫶
  • --verbose — verbose module output. she's chatty and you love that for her ✨
  • --quiet — quiet module output. she's giving mysterious, silent, main character energy 💀
  • --ui — force launching GUI dialog. for when you want the pretty buttons 🌈

🎀 Parameters 🎀

  • map=name [required] — Name of vector points map for which to edit attributes. Or data source for direct OGR access.
  • layer=string — Layer number or name. Vector features can have category values in different layers. This number determines which layer to use. When used with direct OGR access this is the layer name. Default: 1
  • raster_3d=name [required] — Name of existing 3D raster map to be queried. the source of the tea, the oracle, the whole vibe 🔮
  • column=name [required] — Name of attribute column to be updated with the query result. that's where the answers go bestie 📥
  • where=sql_query — WHERE conditions of SQL statement without 'where' keyword. Example: income < 1000 and population >= 10000. you're just giving her the filter, not the whole sentence. periodt.

💜 DESCRIPTION 💜

okay so here's the lore. v.what.rast3 reads a 3D raster value for each point in the vector and updates the col column in the vector attribute table by this value. the column should be type double — like, that's non-negotiable, she needs the precision okay 😭

this module is based on v.what.rast. she's got the same DNA, just taller (three dimensions, bestie, three!!).

If more points have the same category, attribute value is set to NULL. If 3D raster values is NULL, attribute value is set to NULL. so basically ambiguous situations and missing data both get the silent treatment. iconic honestly.

🧚 NOTES 🧚

(the original leaves this one empty, and honestly? a mood. nothing to add, she said what she said.) 💅

🔥 EXAMPLES 🔥

A) Reading values from 3D raster map at position of vector points, writing these values into a column of the attribute table connected to the vector map:

v.what.rast3 map=pnts raster3d=plume column=concentration

B) In case of a vector map without attached attribute table, first add a new attribute table. This table is then populated with values queried from the raster map:

# create new random 3d vector points map
v.random -z output=pnts npoints=100 zmin=0  zmax=50
# add new table, link to map
v.db.addtable map=pnts column="concentration double precision"
# query raster map and upload values to vector table into specified column
g.region raster3d=plume -p
v.what.rast3 map=pnts raster3d=plume column=concentration
# verify new attribute table:
v.db.select map=pnts
# verify statistics of uploaded values:
v.univar map=pnts column=concentration type=point

like?? the way she builds the whole table from scratch and then fills it with queried values?? she ATE. 👑

🌈 SEE ALSO 🌈

  • v.db.addtable
  • v.db.select
  • v.what.rast
  • v.what.vect
  • v.univar

the whole friend group, fr fr. go say hi to them. 🫶

👑 AUTHOR 👑

Soeren Gebbert, heavily based on v.what.rast by Radim Blazek

shoutout to the icons who built her. 🎀

💖 SOURCE CODE 💖

Available at: v.what.rast3 source code (history)

Accessed: Saturday Jan 17 05:41:33 2026

Main index | Vector index | Topics index | Keywords index | Graphical index | Full index

and that's the whole page bestie!! 💜 this is GRASS GIS 8.4.2 Reference Manual material, © 2003-2025 GRASS Development Team, and you're reading the GRASS 8.4.2 version of v.what.rast3(1). go query something, 3D is the moment. 🦋✨🌸

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