v.rast.stats  Calculates univariate statistics from a raster map
based on a vector map and uploads statistics to new attribute columns.
vector, statistics, raster, univariate statistics, zonal statistics, sampling,
querying
v.rast.stats
v.rast.stats help
v.rast.stats [
cd]
map=
name
[
layer=
string]
raster=
name
column_prefix=
string
[
method=
string[,
string,...]] [
percentile=
integer] [
help] [
verbose]
[
quiet] [
ui]
 c

Continue if upload column(s) already exist
 d

Create densified lines (default: thin lines)
All cells touched by the line will be set, not only those on the render
path
 help

Print usage summary
 verbose

Verbose module output
 quiet

Quiet module output
 ui

Force launching GUI dialog
 map=name [required]

Name of 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
 raster=name [required]

Name of input raster map to calculate statistics from
 column_prefix=string [required]

Column prefix for new attribute columns
 method=string[,string,...]

The methods to use
Options: number, minimum, maximum, range, average, stddev, variance,
coeff_var, sum, first_quartile, median, third_quartile, percentile
Default:
number,minimum,maximum,range,average,stddev,variance,coeff_var,sum,first_quartile,median,third_quartile,percentile
 percentile=integer

Percentile to calculate
Options: 0100
Default: 90
v.rast.stats calculates basic univariate statistics from a raster map
only for the parts covered by the specified vector map. The vector map will be
rasterized according to the raster map resolution. Then univariate statistics
are calculated per vector category (cat) from the raster map and the results
uploaded to the vector map attribute table. A new column is generated in the
attribute table for each statistic requested in
method (if not already
present).
The univariate statistics include the number of raster cells counted, minimum
and maximum cell values, range, average, standard deviation, variance,
coefficient of variation, sum, first quartile, median, third quartile, and
percentile.
v.rast.stats is only meaningful for lines or polygons.
The module may take a long time to run if the raster region contains a large
number of cells. In this case the
verbose flag may be used to track
progress.
The script stops if a (prefixed) upload column is already present in the vector
map attribute table, unless otherwise instructed with the
c continue
flag. The column prefix will be separated from the statistic name with an
underscore. For example with a prefix of "elev" the sum column will
be named elev_sum.
If a DBF database is being used, note that column names are restricted by the
DBF specification to 10 characters. Therefore it is advised to be economical
in the use of the column prefix when using DBF as any additional characters
will be chopped off.
If a MASK is present, it will be restored after the script finished. The script
changes temporarily to the resolution of the given raster map.
Large amounts of system memory can be used when extended statistics (
first_quartile,median,third_quartile,percentile ) are being requested
with a very large region setting. If the region is too large the module should
display memory allocation errors. Basic statistics can be calculated using any
size input region.
Example to upload DEM statistics to ZIP codes vector map (North Carolina sample
dataset):
g.copy vect=zipcodes_wake,myzipcodes_wake
# set computational region to DEM:
g.region raster=elevation p
# calculate DEM statistics, upload to vector map table:
v.rast.stats myzipcodes_wake raster=elevation \
column_prefix=elev method=minimum,maximum,average,range,stddev,percentile \
percentile=95
# verify results:
v.info c myzipcodes_wake
v.db.select myzipcodes_wake
v.univar myzipcodes_wake column=elev_range type=centroid
r.univar, v.univar, v.vect.stats,
v.what.rast, v.what.rast3, v.what.vect
Markus Neteler, CEA (for the EDEN EU/FP6 Project)
Last changed: $Date: 20170215 12:56:19 +0100 (Wed, 15 Feb 2017) $
Available at: v.rast.stats source code (history)
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