NAME
r.stats.zonal - Calculates category or object oriented statistics (accumulator-based statistics).
KEYWORDS
raster,
statistics,
zonal statistics
SYNOPSIS
r.stats.zonal
r.stats.zonal --help
r.stats.zonal [-cr] base=name cover=name method=string output=name [--overwrite] [--help] [--verbose] [--quiet] [--ui]
Flags:
- -c
- Cover values extracted from the category labels of the cover map
- -r
- Create reclass map with statistics as category labels
- --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:
- base=name [required]
- Name of base raster map
- cover=name [required]
- Name of cover raster map
- method=string [required]
- Method of object-based statistic
- Options: count, sum, min, max, range, average, avedev, variance, stddev, skewness, kurtosis, variance2, stddev2, skewness2, kurtosis2
- count: Count of values in specified objects
- sum: Sum of values in specified objects
- min: Minimum of values in specified objects
- max: Maximum of values in specified objects
- range: Range of values (max - min) in specified objects
- average: Average of values in specified objects
- avedev: Average deviation of values in specified objects
- variance: Variance of values in specified objects
- stddev: Standard deviation of values in specified objects
- skewness: Skewness of values in specified objects
- kurtosis: Kurtosis of values in specified objects
- variance2: (2-pass) Variance of values in specified objects
- stddev2: (2-pass) Standard deviation of values in specified objects
- skewness2: (2-pass) Skewness of values in specified objects
- kurtosis2: (2-pass) Kurtosis of values in specified objects
- output=name [required]
- Resultant raster map
r.stats.zonal is a tool to analyse exploratory statistics of a
floating-point "cover layer" according to how it intersects with objects
in a "base layer". A variety of standard statistical measures are possible.
This type of analysis is often called
zonal statistics.
The zones are specified as the
base raster map and
the statistics are computed from cells in the
cover raster map.
Notably, the output of this module is spatial:
The resulting values are recorded as cell values in the
output raster map.
NOTES
r.stats.zonal is intended to be a partial replacement for
r.statistics, with support
for floating-point cover maps at the expense of not supporting
quantiles. For this, see
r.stats.quantile.
In this example, the raster polygon map
zipcodes in the North
Carolina sample dataset is used to calculate zonal raster statistics using
the
elevation raster map:
g.region raster=zipcodes -p
# pixel count in zipcode areas
r.stats.zonal base=zipcodes cover=elevation method=count output=zipcodes_elev_count
r.colors zipcodes_elev_count color=gyr -g
# average elevation in zipcode areas
r.stats.zonal base=zipcodes cover=elevation method=average output=zipcodes_elev_avg
r.colors zipcodes_elev_avg color=elevation -g
Figure: ZIP code map on the left shows ZIP code areas,
elevation map the respective values per pixel,
zonal statistics map on the right shows the average elevation per zone
(all maps: spatial subset).
-
r.stats.quantile
for computing quantiles in zones (objects in base raster map),
-
r.quantile
for computing quantiles of a whole raster map,
-
r.statistics
for categorical (integer) zonal statistics,
-
r.univar
for zonal statistics with textual (non-spatial) output,
-
v.vect.stats
for statistics of vector points in vector areas.
Glynn Clements
SOURCE CODE
Available at:
r.stats.zonal source code
(history)
Latest change: Wednesday Jul 10 23:03:36 2024 in commit: 6b38ffbc1004d735db0797abd170f0eaf4c4cd43
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GRASS Development Team,
GRASS GIS 8.5.0dev Reference Manual