v.neighborhoodmatrix

Exports the neighborhood matrix of polygons in a vector map

v.neighborhoodmatrix [-b] input=name [player=integer] [idcolumn=name] [output=name] [separator=character] [--overwrite] [--verbose] [--quiet] [--qq] [--ui]

Example:

v.neighborhoodmatrix input=name

grass.script.run_command("v.neighborhoodmatrix", input, player=1, idcolumn=None, output=None, separator="pipe", flags=None, overwrite=False, verbose=False, quiet=False, superquiet=False)

Example:

gs.run_command("v.neighborhoodmatrix", input="name")

Parameters

Command linePython (grass.script)

input=name [required]
    Name of input vector map
    Or data source for direct OGR access
player=integer
    Layer in map where polygons are to be found
    Default: 1
idcolumn=name
    Name of column containing polygon ids
output=name
    Name for output file (if omitted or "-" output to stdout)
separator=character
    Field separator
    Special characters: pipe, comma, space, tab, newline
    Default: pipe
-b
    create bidirectional matrix (same neighborhood relation repeated twice)
--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
player : int, optional
    Layer in map where polygons are to be found
    Default: 1
idcolumn : str, optional
    Name of column containing polygon ids
    Used as: input, dbcolumn, name
output : str, optional
    Name for output file (if omitted or "-" output to stdout)
    Used as: output, file, name
separator : str, optional
    Field separator
    Special characters: pipe, comma, space, tab, newline
    Used as: input, separator, character
    Default: pipe
flags : str, optional
    Allowed values: b
    b
        create bidirectional matrix (same neighborhood relation repeated twice)
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.neighborhoodmatrix identifies all adjacency relations between polygons in a vector map and exports these as a 2xn matrix where n is the number of neighborhood relations with each relation only listed in one direction (i.e. if a is neighbor of b, the list will contain a,b, but not b,a) unless the b flag is specified. By default, neighbors are identified by the category numbers. Using the idcolumn parameter the user can define a column to use as identifier of the polygons. If a path to an output file is specified, the matrix will be written to that file, otherwise it will be sent to standard output.

NOTES

Currently the module assumes that the layer above the layer containing the polygons is empty and available for adding categories to boundaries. The module uses v.to.db to determine neighborhood relations.

EXAMPLE

Send the neighborhood matrix of the census tracts of the North Carolina dataset to standard output identifying each tract by its category value:

v.neighborhoodmatrix in=census_wake2000

Idem, but identifying each tract by its STFID code and sending the output to a file:

v.neighborhoodmatrix in=census_wake2000 idcolumn=STFID output=census_neighbors.csv

AUTHOR

Moritz Lennert

SOURCE CODE

Available at: v.neighborhoodmatrix source code (history)
Latest change: Thursday Feb 20 13:02:26 2025 in commit 53de819