NAME

       v.neighbors  - Neighborhood analysis tool for vector point maps.
       Makes  each cell value a function of the attribute values assigned to the vector points or centroids in a
       radius around it, and stores new cell values in an output raster map.

KEYWORDS

       vector, algebra, statistics, raster, aggregation

SYNOPSIS

       v.neighbors
       v.neighbors --help
       v.neighbors  input=name   [layer=string]   output=name  method=string  size=float    [points_column=name]
       [cats=range]   [where=sql_query]   [--overwrite]  [--help]  [--verbose]  [--quiet]  [--ui]

   Flags:
       --overwrite
           Allow output files to overwrite existing files

       --help
           Print usage summary

       --verbose
           Verbose module output

       --quiet
           Quiet module output

       --ui
           Force launching GUI dialog

   Parameters:
       input=name [required]
           Name of input vector map
           Or data source for direct OGR access

       layer=string
           Layer number or name
           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

       output=name [required]
           Name for output raster map

       method=string [required]
           Method for aggregate statistics (count if non given)
           Options: count, sum, average, median, mode, minimum, maximum, range, stddev, variance, diversity
           Default: count

       size=float [required]
           Neighborhood diameter in map units

       points_column=name
           Column name of points map to use for statistics
           Column of points map must be numeric

       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

DESCRIPTION

       This module makes each cell value a function of the attribute values assigned to  the  vector  points  or
       centroids in an area around the cell with a diameter of size around it, and stores the new cell values in
       the  output  raster map layer. By default, the module just counts the number of points. The user can also
       choose amongst a variety of aggregate  statistics  using  the  parameter  method.  These  statistics  are
       calculated  on the attributes in the point_column. Using the usual cats and where parameters the user can
       chose to take only a subset of the points into account.

       Note that size is defined as the diameter, and so has to be twice the wanted search radius, and that  the
       module  works within the current computational region which can be adjusted using g.region. If the vector
       map falls completely outside the current region, the module will stop with an error.

EXAMPLE

       Count the number of schools for a given grid (North Carolina sample dataset):
       g.region vector=schools_wake res=100 -p -a
       v.neighbors input=schools_wake output=schools_wake_3000m method=count size=3000
       d.mon wx0
       d.rast schools_wake_3000m
       d.vect schools_wake
       The result gives for each grid cell the number of points (here: schools) not farther than 1500 meter away
       (half of the given size value) from the respective cell center.

       Calculate the mean capacity of schools for the same grid:
       v.neighbors input=schools_wake output=schools_capacity point_column=CAPACITYTO \
                   method=average size=3000

SEE ALSO

        r.neighbors, v.vect.stats

AUTHORS

       Radim Blazek,
       Moritz Lennert

SOURCE CODE

       Available at: v.neighbors source code (history)

       Accessed: Monday Apr 01 03:08:42 2024

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

       © 2003-2024 GRASS Development Team, GRASS GIS 8.3.2 Reference Manual

GRASS 8.3.2                                                                                  v.neighbors(1grass)