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