v.net.allpairs

Computes the shortest path between all pairs of nodes in the network.

Command linePython (grass.script)

v.net.allpairs [-g] input=name output=name [arc_layer=string] [node_layer=string] [cats=range] [where=sql_query] [arc_column=name] [arc_backward_column=name] [node_column=string] [--overwrite] [--verbose] [--quiet] [--qq] [--ui]

Example:

v.net.allpairs input=name output=name

grass.script.run_command("v.net.allpairs", input, output, arc_layer="1", node_layer="2", cats=None, where=None, arc_column=None, arc_backward_column=None, node_column=None, flags=None, overwrite=False, verbose=False, quiet=False, superquiet=False)

Example:

gs.run_command("v.net.allpairs", input="name", output="name")

Parameters

Command linePython (grass.script)

input=name [required]
    Name of input vector map
    Or data source for direct OGR access
output=name [required]
    Name for output vector map
arc_layer=string
    Arc layer
    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
node_layer=string
    Node layer
    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: 2
cats=range
    Category values
    Example: 1,3,7-9,13
where=sql_query
    WHERE conditions of SQL statement without 'where' keyword
    Example: income < 1000 and population >= 10000
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)
-g
    Use geodesic calculation for longitude-latitude projects
--overwrite
    Allow output files to overwrite existing files
--help
    Print usage summary
--verbose
    Verbose module output
--quiet
    Quiet module output
--qq
    Very quiet module output
--ui
    Force launching GUI dialog

input : str, required
    Name of input vector map
    Or data source for direct OGR access
    Used as: input, vector, name
output : str, required
    Name for output vector map
    Used as: output, vector, name
arc_layer : str, optional
    Arc layer
    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.
    Used as: input, layer
    Default: 1
node_layer : str, optional
    Node layer
    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.
    Used as: input, layer
    Default: 2
cats : str, optional
    Category values
    Example: 1,3,7-9,13
    Used as: input, cats, range
where : str, optional
    WHERE conditions of SQL statement without 'where' keyword
    Example: income < 1000 and population >= 10000
    Used as: input, sql_query, sql_query
arc_column : str, optional
    Arc forward/both direction(s) cost column (number)
    Used as: input, dbcolumn, name
arc_backward_column : str, optional
    Arc backward direction cost column (number)
    Used as: input, dbcolumn, name
node_column : str, optional
    Node cost column (number)
flags : str, optional
    Allowed values: g
    g
        Use geodesic calculation for longitude-latitude projects
overwrite: bool, optional
    Allow output files to overwrite existing files
    Default: False
verbose: bool, optional
    Verbose module output
    Default: False
quiet: bool, optional
    Quiet module output
    Default: False
superquiet: bool, optional
    Very quiet module output
    Default: False

DESCRIPTION

v.net.allpairs computes the shortest path between each selected node and all other selected nodes. The output is a vector with the selected nodes and the shortest paths.

NOTES

An attribute table is created and linked to layer arc_layer. The table contains four columns: cat, from_cat, to_cat, cost. Each cat entry denotes the category of the shortest path from the node with category from_cat to the node with category to_cat. If points are specified by cats, layer or where parameters then the table is filled only for the selected points.
If arc_backward_column is not given then then the same costs are used for forward and backward arcs.

EXAMPLE

Find shortest path along roads from selected archsites (Spearfish sample dataset):

# prepare network: connect archsites to roads with threshold 200
v.net input=roads@PERMANENT points=archsites@PERMANENT \
output=roads_net operation=connect thresh=200

# verify result
v.category input=roads_net option=report

# only lines should have a category in layer 1
# only points should have a category in layer 2

# shortest path between all points with categories 1 - 5 in layer 2
v.net.allpairs input=roads_net cats=1-5 out=roads_net_all
v.db.select roads_net_all

Result in matrix form:

from\to 1       3       4       5
1   0       18820.386   17206.651   17373.274
3   18820.386   0       1739.079    9040.575
4   17206.651   1739.079    0       7426.84
5   17373.274   9040.575    7426.84     0

AUTHORS

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

SOURCE CODE

Available at: v.net.allpairs source code (history)
Latest change: Friday Feb 07 19:16:09 2025 in commit a82a39f