1r3.univar(1) GRASS GIS User's Manual r3.univar(1)
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6 r3.univar - Calculates univariate statistics from the non-null cells
7 of a 3D raster map.
8 Statistics include number of cells counted, minimum and maximum cell
9 values, range, arithmetic mean, population variance, standard devia‐
10 tion, coefficient of variation, and sum.
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13 raster3d, statistics, univariate statistics
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16 r3.univar
17 r3.univar --help
18 r3.univar [-get] map=name [zones=name] [output=name] [per‐
19 centile=float[,float,...]] [separator=character] [--overwrite]
20 [--help] [--verbose] [--quiet] [--ui]
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22 Flags:
23 -g
24 Print the stats in shell script style
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26 -e
27 Calculate extended statistics
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29 -t
30 Table output format instead of standard output format
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32 --overwrite
33 Allow output files to overwrite existing files
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35 --help
36 Print usage summary
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38 --verbose
39 Verbose module output
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41 --quiet
42 Quiet module output
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44 --ui
45 Force launching GUI dialog
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47 Parameters:
48 map=name [required]
49 Name of 3D raster map
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51 zones=name
52 3D Raster map used for zoning, must be of type CELL
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54 output=name
55 Name for output file (if omitted or "-" output to stdout)
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57 percentile=float[,float,...]
58 Percentile to calculate (requires extended statistics flag)
59 Options: 0-100
60 Default: 90
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62 separator=character
63 Field separator
64 Special characters: pipe, comma, space, tab, newline
65 Default: pipe
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68 r3.univar calculates the univariate statistics for a 3D raster map.
69 This includes the number of cells counted, minimum and maximum cell
70 values, range, arithmetic mean, population variance, standard devia‐
71 tion, coefficient of variation, and sum. Statistics are calculated sep‐
72 arately for every category/zone found in the zones input map if given.
73 If the -e extended statistics flag is given the 1st quartile, median,
74 3rd quartile, and given percentile are calculated. If the -g flag is
75 given the results are presented in a format suitable for use in a shell
76 script. If the -t flag is given the results are presented in tabular
77 format with the given field separator. The table can immediately be
78 converted to a vector attribute table which can then be linked to a
79 vector, e.g. the vector that was rasterized to create the zones input
80 raster.
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83 As with most GRASS raster3d modules, r3.univar operates on the voxel
84 array defined by the current 3d region settings, not the original
85 extent and resolution of the input map. See g.region.
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87 This module can use large amounts of system memory when the -e extended
88 statistics flag is used with a very large region setting. If the region
89 is too large the module should exit gracefully with a memory allocation
90 error. Basic statistics can be calculated using any size input region.
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93 Computing univariate statistics of a 3D raster with randomly generated
94 values:
95 # define volume
96 g.region n=10 s=0 w=0 e=10 b=0 t=10 res=1 res3=1 -p3
97 # generate random map
98 r3.mapcalc "random_0_1 = rand(0., 1)" -s
99 # compute univariate statistics, along with extended statistics
100 r3.univar -e map=random_0_1 percentile=98
101 100%
102 total null and non-null cells: 1000
103 total null cells: 0
104 Of the non-null cells:
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106 n: 1000
107 minimum: 0.00053905
108 maximum: 0.998322
109 range: 0.997783
110 mean: 0.513676
111 mean of absolute values: 0.513676
112 standard deviation: 0.289969
113 variance: 0.0840821
114 variation coefficient: 56.4498 %
115 sum: 513.676463040334
116 1st quartile: 0.257654
117 median (even number of cells): 0.524313
118 3rd quartile: 0.763637
119 98th percentile: 0.982924
120 # script style output, along with extended statistics
121 r3.univar -ge map=random_0_1 percentile=98
122 n=1000
123 null_cells=0
124 cells=1000
125 min=0.000539049520323687
126 max=0.998322037540536
127 range=0.997782988020212
128 mean=0.513676463040334
129 mean_of_abs=0.513676463040334
130 stddev=0.289969154194666
131 variance=0.0840821103843701
132 coeff_var=56.4497646005434
133 sum=513.676463040334
134 first_quartile=0.257654
135 median=0.524313
136 third_quartile=0.763637
137 percentile_98=0.982924
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140 To be implemented mode, skewness, kurtosis.
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143 g.region, r.univar, r.mode, r.quantile, r.series, r3.stats, r.statis‐
144 tics, v.rast.stats, v.univar
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147 Soeren Gebbert
148 Code is based on r.univar from
149 Hamish Bowman, Otago University, New Zealand
150 and Martin Landa
151 Zonal loop by Markus Metz
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154 Available at: r3.univar source code (history)
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156 Main index | 3D raster index | Topics index | Keywords index | Graphi‐
157 cal index | Full index
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159 © 2003-2020 GRASS Development Team, GRASS GIS 7.8.5 Reference Manual
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163GRASS 7.8.5 r3.univar(1)