v.net.components(1)

📦
version 8.4.2 · 8 versions
, in fedora 44

💖 v.net.components 💖

okay bestie, welcome to the GRASS GIS User's Manual page for v.net.components(1) — yes that's the man page name, no I will not be normal about it ✨

🌈 NAME 🌈

v.net.components — computes strongly and weakly connected components in the network. that's the whole vibe. it finds the friend groups in your network graph 🫶

🎀 KEYWORDS 🎀

vector, network, components

✨ SYNOPSIS ✨

v.net.components
v.net.components --help
v.net.components [-a] input=name  [arc_layer=string]
[arc_layer=string]   [node_layer=string]   [arc_column=name]   [arc_backward_column=name]
[node_column=string]  output=name method=string  [--overwrite]  [--help]
[--verbose]  [--quiet]  [--ui]

okay let me redo that properly, exact characters, no autocorrect energy:

v.net.components
v.net.components --help
v.net.components [-a] input=name  [arc_layer=string]
[node_layer=string]   [arc_column=name]   [arc_backward_column=name]
[node_column=string]  output=name method=string  [--overwrite]  [--help]
[--verbose]  [--quiet]  [--ui]

🚩 Flags 🚩

  • -a — add points on nodes. like, the module will literally place new points for you 💅
  • --overwrite — allow output files to overwrite existing files (she will absolutely replace your old files if you say yes, so be sure bestie)
  • --help — print usage summary
  • --verbose — verbose module output (she talks more, we love a chatty queen)
  • --quiet — quiet module output (she shuts up, respectfully)
  • --ui — force launching GUI dialog

🦋 Parameters 🦋

  • input=name [required] — name of input vector map. or, plot twist, a data source for direct OGR access 🌸
  • arc_layer=string — arc layer. vector features can have category values in different layers, and this number determines which layer to use. when you're doing direct OGR access, this is the layer name instead. Default: 1
  • node_layer=string — node layer. same deal: vector features can have category values in different layers, this number picks which one. with direct OGR access it's the layer name. Default: 2
  • arc_column=name — arc forward/both direction(s) cost column (number)
  • arc_backward_column=name — arc backward direction cost column (number)
  • node_column=string — node cost column (number)
  • output=name [required] — name for output vector map
  • method=string [required] — type of components
    • Options: weak, strong
    • weak: weakly connected components
    • strong: strongly connected components

💜 DESCRIPTION 💜

v.net.components computes the weakly and strongly connected components in a network. that's it, that's the job, and she does it flawlessly no cap 👑

🔥 NOTES 🔥

Two nodes, u and v, are in the same strongly connected component if there are directed paths from u to v and from v to u. mutual travel, mutual respect, iconic. The nodes are in the same weakly connected component if, ignoring edge directions, there is a path between them — so even if the arrows don't line up, as long as you can get there ignoring direction, you're in the same group 💫

The type of components is specified by the method parameter. v.net.components creates a table and links it to layer 1. This table contains only two integer columns: cat and comp. If a point or both endpoints of a line belong to the same component then the point/line is written to the output map and appropriate information is stored in the table. If the -a flag is set then new points are added on the nodes without points. These points have category numbers larger than any category used in the input map. noted, no notes missed, periodt ✍️

One-way roads can be defined by assigning a cost of -1 to the appropriate cost column (arc_column or arc_backward_column). This affects only strongly connected components. Network nodes can be closed by assigning a cost of -1 to the node cost column. All nodes with a cost < 0 can not be traversed and are end points, while all nodes with a cost ≥ 0 can be traversed. This affects both weakly and strongly connected components.

ngl that < 0 / ≥ 0 bit is doing a LOT of heavy lifting, so read it twice bestie 😭

🌸 EXAMPLES 🌸

Any road network should form a single strongly connected component. Otherwise, it is impossible to travel between some places. lowkey terrifying but okay 🚗

v.net.components input=roads output=roads_components method=strong

⭐ SEE ALSO ⭐

v.net, v.category

👑 AUTHORS 👑

  • Daniel Bundala, Google Summer of Code 2009, Student
  • Wolf Bergenheim, Mentor
  • Markus Metz

💀 SOURCE CODE 💀

Available at: v.net.components source code (history)

Accessed: Saturday Jan 17 05:41:26 2026

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

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

and that's the whole page bestie 🫶 this was v.net.components(1) from GRASS 8.4.2, dated Saturday Jan 17 05:41:26 2026 — go compute some components, you got this 💅✨

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