Note: This document is for an older version of GRASS GIS that will be discontinued soon. You should upgrade, and read the current manual page.

## 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

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.

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

*
r.neighbors,
v.vect.stats
*
Radim Blazek,

Moritz Lennert

## SOURCE CODE

Available at:
v.neighbors source code
(history)

Latest change: Thursday Jan 26 14:10:26 2023 in commit: cdd84c130cea04b204479e2efdc75c742efc4843

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GRASS Development Team,
GRASS GIS 8.3.3dev Reference Manual