---
name: v.net.spanningtree
description: "Computes minimum spanning tree for the network."
keywords: [ vector, network, spanning tree ]
---

# v.net.spanningtree

Computes minimum spanning tree for the network.

=== "Command line"

    **v.net.spanningtree**
    [**-g**]
    **input**=*name*
    **output**=*name*
    [**arc_layer**=*string*]
    [**node_layer**=*string*]
    [**arc_column**=*name*]
    [**node_column**=*name*]
    [**--overwrite**]
    [**--verbose**]
    [**--quiet**]
    [**--qq**]
    [**--ui**]

    Example:

    ```sh
    v.net.spanningtree input=name output=name
    ```

=== "Python (grass.tools)"

    *grass.tools.Tools.v_net_spanningtree*(**input**,
        **output**,
        **arc_layer**=*"1"*,
        **node_layer**=*"2"*,
        **arc_column**=*None*,
        **node_column**=*None*,
        **flags**=*None*,
        **overwrite**=*None*,
        **verbose**=*None*,
        **quiet**=*None*,
        **superquiet**=*None*)

    Example:

    ```python
    tools = Tools()
    tools.v_net_spanningtree(input="name", output="name")
    ```

    This grass.tools API is experimental in version 8.5 and expected to be stable in version 8.6.

=== "Python (grass.script)"

    *grass.script.run_command*("***v.net.spanningtree***",
        **input**,
        **output**,
        **arc_layer**=*"1"*,
        **node_layer**=*"2"*,
        **arc_column**=*None*,
        **node_column**=*None*,
        **flags**=*None*,
        **overwrite**=*None*,
        **verbose**=*None*,
        **quiet**=*None*,
        **superquiet**=*None*)

    Example:

    ```python
    gs.run_command("v.net.spanningtree", input="name", output="name")
    ```

## Parameters

=== "Command line"

    **input**=*name* **[required]**  
    &nbsp;&nbsp;&nbsp;&nbsp;Name of input vector map  
    &nbsp;&nbsp;&nbsp;&nbsp;Or data source for direct OGR access  
    **output**=*name* **[required]**  
    &nbsp;&nbsp;&nbsp;&nbsp;Name for output vector map  
    **arc_layer**=*string*  
    &nbsp;&nbsp;&nbsp;&nbsp;Arc layer  
    &nbsp;&nbsp;&nbsp;&nbsp;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.  
    &nbsp;&nbsp;&nbsp;&nbsp;Default: *1*  
    **node_layer**=*string*  
    &nbsp;&nbsp;&nbsp;&nbsp;Node layer  
    &nbsp;&nbsp;&nbsp;&nbsp;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.  
    &nbsp;&nbsp;&nbsp;&nbsp;Default: *2*  
    **arc_column**=*name*  
    &nbsp;&nbsp;&nbsp;&nbsp;Arc forward/both direction(s) cost column (number)  
    **node_column**=*name*  
    &nbsp;&nbsp;&nbsp;&nbsp;Node cost column (number)  
    **-g**  
    &nbsp;&nbsp;&nbsp;&nbsp;Use geodesic calculation for longitude-latitude projects  
    **--overwrite**  
    &nbsp;&nbsp;&nbsp;&nbsp;Allow output files to overwrite existing files  
    **--help**  
    &nbsp;&nbsp;&nbsp;&nbsp;Print usage summary  
    **--verbose**  
    &nbsp;&nbsp;&nbsp;&nbsp;Verbose module output  
    **--quiet**  
    &nbsp;&nbsp;&nbsp;&nbsp;Quiet module output  
    **--qq**  
    &nbsp;&nbsp;&nbsp;&nbsp;Very quiet module output  
    **--ui**  
    &nbsp;&nbsp;&nbsp;&nbsp;Force launching GUI dialog

=== "Python (grass.tools)"

    **input** : str, *required*  
    &nbsp;&nbsp;&nbsp;&nbsp;Name of input vector map  
    &nbsp;&nbsp;&nbsp;&nbsp;Or data source for direct OGR access  
    &nbsp;&nbsp;&nbsp;&nbsp;Used as: input, vector, *name*  
    **output** : str, *required*  
    &nbsp;&nbsp;&nbsp;&nbsp;Name for output vector map  
    &nbsp;&nbsp;&nbsp;&nbsp;Used as: output, vector, *name*  
    **arc_layer** : str, *optional*  
    &nbsp;&nbsp;&nbsp;&nbsp;Arc layer  
    &nbsp;&nbsp;&nbsp;&nbsp;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.  
    &nbsp;&nbsp;&nbsp;&nbsp;Used as: input, layer  
    &nbsp;&nbsp;&nbsp;&nbsp;Default: *1*  
    **node_layer** : str, *optional*  
    &nbsp;&nbsp;&nbsp;&nbsp;Node layer  
    &nbsp;&nbsp;&nbsp;&nbsp;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.  
    &nbsp;&nbsp;&nbsp;&nbsp;Used as: input, layer  
    &nbsp;&nbsp;&nbsp;&nbsp;Default: *2*  
    **arc_column** : str, *optional*  
    &nbsp;&nbsp;&nbsp;&nbsp;Arc forward/both direction(s) cost column (number)  
    &nbsp;&nbsp;&nbsp;&nbsp;Used as: input, dbcolumn, *name*  
    **node_column** : str, *optional*  
    &nbsp;&nbsp;&nbsp;&nbsp;Node cost column (number)  
    &nbsp;&nbsp;&nbsp;&nbsp;Used as: input, dbcolumn, *name*  
    **flags** : str, *optional*  
    &nbsp;&nbsp;&nbsp;&nbsp;Allowed values: *g*  
    &nbsp;&nbsp;&nbsp;&nbsp;**g**  
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Use geodesic calculation for longitude-latitude projects  
    **overwrite** : bool, *optional*  
    &nbsp;&nbsp;&nbsp;&nbsp;Allow output files to overwrite existing files  
    &nbsp;&nbsp;&nbsp;&nbsp;Default: *None*  
    **verbose** : bool, *optional*  
    &nbsp;&nbsp;&nbsp;&nbsp;Verbose module output  
    &nbsp;&nbsp;&nbsp;&nbsp;Default: *None*  
    **quiet** : bool, *optional*  
    &nbsp;&nbsp;&nbsp;&nbsp;Quiet module output  
    &nbsp;&nbsp;&nbsp;&nbsp;Default: *None*  
    **superquiet** : bool, *optional*  
    &nbsp;&nbsp;&nbsp;&nbsp;Very quiet module output  
    &nbsp;&nbsp;&nbsp;&nbsp;Default: *None*  

    Returns:

    **result** : grass.tools.support.ToolResult | None  
    If the tool produces text as standard output, a *ToolResult* object will be returned. Otherwise, `None` will be returned.

    Raises:

    *grass.tools.ToolError*: When the tool ended with an error.

=== "Python (grass.script)"

    **input** : str, *required*  
    &nbsp;&nbsp;&nbsp;&nbsp;Name of input vector map  
    &nbsp;&nbsp;&nbsp;&nbsp;Or data source for direct OGR access  
    &nbsp;&nbsp;&nbsp;&nbsp;Used as: input, vector, *name*  
    **output** : str, *required*  
    &nbsp;&nbsp;&nbsp;&nbsp;Name for output vector map  
    &nbsp;&nbsp;&nbsp;&nbsp;Used as: output, vector, *name*  
    **arc_layer** : str, *optional*  
    &nbsp;&nbsp;&nbsp;&nbsp;Arc layer  
    &nbsp;&nbsp;&nbsp;&nbsp;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.  
    &nbsp;&nbsp;&nbsp;&nbsp;Used as: input, layer  
    &nbsp;&nbsp;&nbsp;&nbsp;Default: *1*  
    **node_layer** : str, *optional*  
    &nbsp;&nbsp;&nbsp;&nbsp;Node layer  
    &nbsp;&nbsp;&nbsp;&nbsp;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.  
    &nbsp;&nbsp;&nbsp;&nbsp;Used as: input, layer  
    &nbsp;&nbsp;&nbsp;&nbsp;Default: *2*  
    **arc_column** : str, *optional*  
    &nbsp;&nbsp;&nbsp;&nbsp;Arc forward/both direction(s) cost column (number)  
    &nbsp;&nbsp;&nbsp;&nbsp;Used as: input, dbcolumn, *name*  
    **node_column** : str, *optional*  
    &nbsp;&nbsp;&nbsp;&nbsp;Node cost column (number)  
    &nbsp;&nbsp;&nbsp;&nbsp;Used as: input, dbcolumn, *name*  
    **flags** : str, *optional*  
    &nbsp;&nbsp;&nbsp;&nbsp;Allowed values: *g*  
    &nbsp;&nbsp;&nbsp;&nbsp;**g**  
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Use geodesic calculation for longitude-latitude projects  
    **overwrite** : bool, *optional*  
    &nbsp;&nbsp;&nbsp;&nbsp;Allow output files to overwrite existing files  
    &nbsp;&nbsp;&nbsp;&nbsp;Default: *None*  
    **verbose** : bool, *optional*  
    &nbsp;&nbsp;&nbsp;&nbsp;Verbose module output  
    &nbsp;&nbsp;&nbsp;&nbsp;Default: *None*  
    **quiet** : bool, *optional*  
    &nbsp;&nbsp;&nbsp;&nbsp;Quiet module output  
    &nbsp;&nbsp;&nbsp;&nbsp;Default: *None*  
    **superquiet** : bool, *optional*  
    &nbsp;&nbsp;&nbsp;&nbsp;Very quiet module output  
    &nbsp;&nbsp;&nbsp;&nbsp;Default: *None*

## DESCRIPTION

*v.net.spanningtree* finds the minimum spanning tree in a network.

## NOTES

A spanning tree is a minimum cost subnetwork connecting all nodes in an
undirected network (same forward and backward costs). If a network is
disconnected then the module computes the minimum spanning tree for each
(weakly) connected component. So, strictly speaking,
*v.net.spanningtree* does not compute spanning tree but a spanning
forest. As the name suggests, a spanning tree is a tree. That is, it
contains no cycles and if a component has N nodes then the tree has N-1
edges connecting all nodes. **Accol** is used to specify the costs of
the edges. The **output** consists of the edges in the spanning tree.

## EXAMPLES

Find cheapest set of pipelines connecting all nodes.

```sh
v.net.spanningtree input=projected_pipelines output=spanningtree accol=cost
```

## SEE ALSO

*[v.net](v.net.md), [v.net.steiner](v.net.steiner.md)*

## AUTHORS

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

## SOURCE CODE

Available at: [v.net.spanningtree source code](https://github.com/OSGeo/grass/tree/main/vector/v.net.spanningtree)
([history](https://github.com/OSGeo/grass/commits/main/vector/v.net.spanningcommits))  
Latest change: Friday Feb 07 19:16:09 2025 in commit [a82a39f](https://github.com/OSGeo/grass/commit/a82a39f673b97fafcfce1604dc3e6015cb96487a)
