GRASS GIS manual: r.stats

Note: A new GRASS GIS stable version has been released: GRASS GIS 7.4, available here.
Updated manual page: here

NAME

r.stats - Generates area statistics for raster map.

KEYWORDS

raster, statistics

SYNOPSIS

r.stats

r.stats --help

r.stats [-acpl1gxArnNCi] input=name[,name,...] [output=name] [separator=character] [null_value=string] [nsteps=integer] [sort=string] [--overwrite] [--help] [--verbose] [--quiet] [--ui]

Flags:

-a: Print area totals in square meters
-c: Print cell counts (sortable)
-p: Print approximate (total percent may not be 100%) percents
-l: Print category labels
-1: One cell (range) per line
-g: Print grid coordinates (east and north)
-x: Print x and y (column and row)
-A: Print averaged values instead of intervals (floating-point maps only)
-r: Print raw indexes of floating-point ranges (floating-point maps only)
-n: Do not report no data value
-N: Do not report cells where all maps have no data
-C: Report for cats floating-point ranges (floating-point maps only)
-i: Read floating-point map as integer (use map's quant rules)
--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[,name,...] [required]: Name of raster map(s) to report on
output=name: Name for output file (if omitted or "-" output to stdout)
separator=character: Field separator; Special characters: pipe, comma, space, tab, newline; Default: space
null_value=string: String representing NULL value; Default: *
nsteps=integer: Number of floating-point subranges to collect stats from; Default: 255
sort=string: Sort output statistics by cell counts; Default: sorted by categories or intervals; Options: asc, desc; asc: Sort by cell counts in ascending order; desc: Sort by cell counts in descending order

DESCRIPTION
NOTES
EXAMPLES
SEE ALSO
AUTHORS

DESCRIPTION

r.stats calculates the area present in each of the categories or floating-point intervals of user-selected input raster map. Area statistics are given in units of square meters and/or cell counts. This analysis uses the current geographic region (g.region) and mask settings (r.mask). The output statistics can be saved to a output file.

Area statistics is printed in square meters for each category when -a is given. Similarly if -c flag is chosen, areas will be stated also in number of cells.

NOTES

If a single raster map is specified, a list of categories will be printed. If multiple raster maps are specified, a cross-tabulation table for each combination of categories in the raster maps will be printed.

For example, if one raster map was specified, the output would look like:

1 1350000.00
2 4940000.00
3 8870000.00

If three raster maps were specified, the output would look like:

0 0 0 8027500.00
0 1 0 1152500.00
1 0 0 164227500.00
1 0 1 2177500.00
1 1 0 140092500.00
1 1 1 3355000.00
2 0 0 31277500.00
2 0 1 2490000.00
2 1 0 24207500.00
2 1 1 1752500.00
3 0 0 17140000.00
3 1 0 11270000.00
3 1 1 2500.00

Within each grouping, the first field represents the category value of first raster map, the second represents the category values associated with second raster map, the third represents category values for third raster map, and the last field gives the area in square meters for the particular combination of these three raster maps' categories. For example, above, combination 3,1,1 covered 2500 square meters. Fields are separated by the separator option. The output from r.stats is sorted by category or category intervals (for floating-point raster maps).

Note that the user has only the option of printing out cell statistics in terms of cell counts and/or area totals. Users wishing to use different units than are available here should use r.report.

EXAMPLES

Report area for each category in the single raster map:

r.stats -a in=geology_30m nv=no-data sep=tab

217     71960000.000000
262     19760000.000000
270     67760000.000000
405     25120000.000000
583     2520000.000000
720     480000.000000
766     840000.000000
862     6560000.000000
910     4360000.000000
921     1200000.000000
946     360000.000000
948     80000.000000
no-data 33375200000.000004

Report sorted number of cells for each category in the single raster map (suppress NULL data):

r.stats -cn in=geology_30m sort=desc

217 1799
270 1694
405 628
262 494
862 164
910 109
583 63
921 30
766 21
720 12
946 9
948 2

Report area, number of cells, and percents (separated by tabs) for each category in the multiple raster maps (suppress NULL data):

r.stats -nacp in=towns,urban sep=tab

1       55      23840000.000000 596     11.89%
2       55      13680000.000000 342     6.82%
3       55      1360000.000000  34      0.68%
4       55      16040000.000000 401     8.00%
5       55      98240000.000000 2456    48.98%
6       55      19760000.000000 494     9.85%

Report sorted area for each interval of floating-point input raster map. Number of intervals are given by nsteps option.

r.stats -an in=elevation nsteps=10 sort=desc sep=tab

95.879221-105.954329    36440000.000000
85.804114-95.879221     30800000.000000
105.954329-116.029436   30080000.000000
116.029436-126.104543   27960000.000000
126.104543-136.17965    26440000.000000
136.17965-146.254757    20880000.000000
75.729007-85.804114     15880000.000000
65.6539-75.729007       6040000.000000
146.254757-156.329865   5720000.000000
55.578793-65.6539       760000.000000

AUTHORS

Michael Shapiro, U.S. Army Construction Engineering Research Laboratory
Sort option by Martin Landa, Czech Technical University in Prague, 2013

Last changed: $Date: 2014-12-11 15:16:30 -0800 (Thu, 11 Dec 2014) $

SOURCE CODE

Available at: r.stats source code (history)