Flags:¶

-p

Print output to stdout, do not update attribute table
First column is always area category

--help

Print usage summary

--verbose

Verbose module output

--quiet

Quiet module output

--ui

Force launching GUI dialog

Parameters:¶

points=name [required]

Name of input vector map
Name of existing vector map with points

areas=name [required]

Name of input vector map
Name of existing vector map with areas

type=string[,string,...]

Feature type
Input feature type
Options: point, centroid
Default: point

points_layer=string

Layer number for points map
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

areas_layer=string

Layer number for area map
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

method=string

Method for aggregate statistics
Options: sum, average, median, mode, minimum, min_cat, maximum, max_cat, range, stddev, variance, diversity

points_column=name

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

count_column=string

Column name to upload points count
Column to hold points count, must be of type integer, will be created if not existing

stats_column=string

Column name to upload statistics
Column to hold statistics, must be of type double, will be created if not existing

separator=character

Field separator
Special characters: pipe, comma, space, tab, newline
Default: pipe

Preparation for examples¶

# work on map copy for attribute editing
g.copy vector=zipcodes_wake,myzipcodes_wake
# set computational region: extent of ZIP code map, raster pixels
# aligned to raster map
g.region vector=myzipcodes_wake align=elev_state_500m -p
#  generate random elevation points
r.random elev_state_500m vector=rand5000 n=5000
v.colors rand5000 color=elevation
# visualization
d.mon wx0
d.vect myzipcodes_wake -c
d.vect rand5000

Count points per polygon with printed output¶

Counting points per polygon, print results to terminal:

v.vect.stats points=rand5000 area=myzipcodes_wake -p

Count points per polygon with column update¶

Counting of points per polygon, with update of "num_points" column (will be automatically created):

v.vect.stats points=rand5000 area=myzipcodes_wake count_column=num_points
# verify result
v.db.select myzipcodes_wake column=ZIPCODE_,ZIPNAME,num_points

Average values of points in polygon with printed output¶

Calculation of average point elevation per ZIP code polygon, printed to terminal in comma separated style:

# check name of point map column:
v.info -c rand5000
v.vect.stats points=rand5000 area=myzipcodes_wake \
  method=average points_column=value separator=comma -p

Average values of points in polygon with column update¶

Calculation of average point elevation per ZIP code polygon, with update of "avg_elev" column and counting of points per polygon, with update of "num_points" column (new columns will be automatically created):

# check name of point map column:
v.info -c rand5000
v.vect.stats points=rand5000 area=myzipcodes_wake count_column=num_points \
  method=average points_column=value stats_column=avg_elev
# verify result
v.db.select myzipcodes_wake column=ZIPCODE_,ZIPNAME,avg_elev

Point statistics in a hexagonal grid¶

g.region vector=points_of_interest res=2000 -pa

v.mkgrid map=hexagons -h

v.vect.stats points=points_of_interest areas=hexagons method=average \
  points_column=elev_m count_column=count stats_column=average

v.colors map=hexagons use=attr column=average color=viridis