# r3.stats.1grass - Man Page

Generates volume statistics for 3D raster maps.

## Keywords

raster3d, statistics, voxel, volume

## Synopsis

`r3.statsr3.stats --helpr3.stats [-ec] input=name  [nsteps=integer]   [--help]  [--verbose]  [--quiet]  [--ui]`

### Flags

-e

Calculate statistics based on equal value groups

-c

Only print cell counts

--help

Print usage summary

--verbose

Verbose module output

--quiet

Quiet module output

--ui

Force launching GUI dialog

### Parameters

input=nameÂ [required]

Name of input 3D raster map

nsteps=integer

Number of subranges to collect stats from
Default: 20

## Description

r3.stats calculates volume statistics for 3D raster maps. Volumes are created on base of value subranges or groups of equal values. The default number of subranges is 20 and can vary from 1 to infinite. Larger number of subranges will result in larger memory consumption. The volumes are calculated in qubic meters. Null values are marked with "*". If the flag -e is set, the number of subranges will be ignored.

## Examples

### Lausanne FOSS4G 2006 3D demo dataset example

The 3D raster map geology has three values. Each value represents a specific geological layer, clay = 1, sand = 2 and bedrock = 3. To calculate the volume of each geological layer, we can use the flag -e to group equal values into single volumes. r3.stats geology -e will produce the following output:

```  num   |        value       |     volume    |   perc  |    count
1             1.000000   300822000.000   50.13700        50137
2             2.000000   101400000.000   16.90000        16900
3             3.000000   197778000.000   32.96300        32963
4                    *           0.000   0.00000            0
Number of groups with equal values: 3
Sum of non Null cells:
Volume = 600000000.000
Percentage = 100.000
Count = 100000
Sum of all cells:
Volume = 600000000.000
Percentage = 100.000
Count = 100000```

### Generic example

```#create a small 3D region
g.region n=1000 s=0 e=2000 w=0 t=300 b=0 res3=100
#create a raster3D map with row() and null values
r3.mapcalc "volmap = if(row() == 5, null(), row())"
#run r3.stats with a subrange of 10
r3.stats input=volmap nsteps=10
#the result should look like this
num   | minimum <= value   | value < maximum    |     volume    |   perc  | cell count
1          1.000000000          1.900000000    60000000.000   10.00000           60
2          1.900000000          2.800000000    60000000.000   10.00000           60
3          2.800000000          3.700000000    60000000.000   10.00000           60
4          3.700000000          4.600000000    60000000.000   10.00000           60
5          4.600000000          5.500000000           0.000   0.00000            0
6          5.500000000          6.400000000    60000000.000   10.00000           60
7          6.400000000          7.300000000    60000000.000   10.00000           60
8          7.300000000          8.200000000    60000000.000   10.00000           60
9          8.200000000          9.100000000    60000000.000   10.00000           60
10          9.100000000         10.000000001    60000000.000   10.00000           60
11                    *                    *    60000000.000   10.00000           60
Sum of non Null cells:
Volume = 540000000.000
Percentage =  90.000
Cell count = 540
Sum of all cells:
Volume = 600000000.000
Percentage = 100.000
Cell count = 600```

g.region, r3.univar, r.stats, r.statistics, v.univar

SÃ¶ren Gebbert

## Source Code

Available at: r3.stats source code (history)

Accessed: Thursday Jul 20 05:48:54 2023

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Â© 2003-2023 GRASS Development Team, GRASS GIS 8.3.0 Reference Manual

## Info

GRASS 8.3.0 GRASS GIS User's Manual