v.build(1grass)

💖 v.build — the manual page, but make it make sense 💖

okay bestie, welcome to the GRASS User's Manual glow-up edition of v.build(1grass). pull up a chair, grab a boba, and let's talk topology 🧚✨

✨ NAME ✨

v.build — creates topology for vector map. and like, optionally it also checks for topological errors. multitasking icon behavior 💅

🌸 KEYWORDS 🌸

vector, topology, geometry

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🎀 SYNOPSIS 🎀

v.build
v.build --help
v.build [-e] map=name  [error=name]  option=string[,string,...]
[--overwrite]  [--help]  [--verbose]  [--quiet]  [--ui]

🦋 FLAGS 🦋

• -e — Extensive checks for topological errors. this is the "go deep, no half measures" mode: it does in-depth checks for topological errors while building topology 🔍
• --overwrite — Allow output files to overwrite existing files. yes, it will simply replace them. no cap.
• --help — Print usage summary. your lil cheat sheet 🫶
• --verbose — Verbose module output. it will yap. a lot. affectionate.
• --quiet — Quiet module output. it will not yap. shy bae 🙈
• --ui — Force launching GUI dialog. clicking instead of typing, main character energy 👑

🌈 PARAMETERS 🌈

• map=name [required] — Name of vector map. the actual subject of the whole operation, obvi.
• error=name — Name for output vector map where erroneous vector features are written to. the "here's what went wrong" map, for later sleuthing 🕵️
• option=string[,string,...] [required] — Build topology or dump topology or indices to standard output.
  • Options: build, dump, sdump, cdump, fdump
  • Default: build
  • build: build topology
  • dump: write topology to stdout
  • sdump: write spatial index to stdout
  • cdump: write category index to stdout
  • fdump: write feature index to stdout (OGR simple-feature-based formats only)

💜 DESCRIPTION 💜

so what does v.build even do. it builds support files for GRASS vector maps. "support files" being the little entourage that makes everything else work: they supply topology and category information, plus a spatial index, which other GRASS modules literally need to function. it's giving backstage crew at the concert. nobody claps for them but the show does not happen without them 💖

and here's the chill part: GRASS is generating these support files automatically. only in rare cases does the user have to (re)build them. so bestie, you usually don't need this. but when you do… you do.

if you want more lore, refer to vector data processing in GRASS for more info on the GRASS vector data model. iykyk 📚

🔥 NOTES 🔥

• v.build creates support files only for vector maps located in the user's current mapset. it's not possible to rebuild support files (option=build) for vector maps from other mapsets. boundaries, bestie. stay in your lane 🚧
• In case of errors, the user can optionally generate an error vector map containing the erroneous vectors for later inspection. a whole scrapbook of your mistakes, for science 💀
• If error vector map is specified, v.build checks:
  • isolated boundaries (which are not forming any areas)
  • centroids outside of area
  • duplicated centroids
• Extensive checks for topological errors (flag -e) also includes:
  • lines or boundaries of zero length
  • intersecting boundaries, i.e. overlapping areas
  • areas without centroids that are not isles

so basically: without -e you get the first three checks. with -e you get all six. the more you know ⭐

🌸 EXAMPLES 🌸

✨ Build topology ✨

Note that option=build also recreates spatial and category indices, not only topology. For linked OGR layers (see v.external) also feature index is created.

v.build map=urbanarea option=build

Note that the vector map urbanarea must be located in the current mapset. (saying it twice because it matters, sorry not sorry 🙈)

✨ Dump topology or indices ✨

Dump options print topology, spatial, category or feature index to standard output. Such information can also be printed for vector maps from other mapsets. A description of the vector topology is available in the GRASS 8 Programmer's Manual, section "Vector library topology management".

v.build map=urbanarea option=dump

🫶 SEE ALSO 🫶

v.build.all, v.build.polylines, v.edit, v.split, v.support

See also wxGUI vector digitizer.

👑 AUTHORS 👑

Dave Gerdes, U.S.Army Construction Engineering Research Laboratory, Michael Higgins, U.S.Army Construction Engineering Research Laboratory, Radim Blazek, ITC-irst, Trento, Italy

give them their flowers, fr fr 🌷

⭐ SOURCE CODE ⭐

Available at: v.build source code (history)

Latest change: Thursday May 07 14:38:34 2026 in commit: b28fe3135a09de48c06efbbcc108dd7c7e57223f

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

© 2003-2026 GRASS Development Team, GRASS 8.5.0 Reference Manual

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okay that's the whole thing, we ate and left no crumbs 💅 this was the v.build(1grass) page from the GRASS 8.5.0 manual — go build some topology bestie, mwah 🎀✨🦋