1r3.stats(1) Grass User's Manual r3.stats(1)
2
6 r3.stats - Generates volume statistics for raster3d maps.
7
9 raster3d, statistics
10
12 r3.stats
13 r3.stats help
14 r3.stats [-e] input=name [nsteps=integer] [--verbose] [--quiet]
15 Flags:
17 -e
18 Calculate statistics based on equal value groups
19 --verbose
21 Verbose module output
22 --quiet
24 Quiet module output
25 Parameters:
27 input=name
28 Name of input raster3d map
29 nsteps=integer
31 Number of sub-ranges to collect stats from
32 Default: 20
33
35 r3.stats calculates volume statistics for raster3d maps. Volumes are
36 created on base of value subranges or groups of equal values. The
37 default number of subranges is 20 and can vary from 1 to infinite.
38 Larger subranges will result in larger memory consumption. The volumes
39 are calculated in qubic meters. Null values are marked with "*". If
40 the flag -e is set, the number of subrange will be ignored.
41
43 As with most GRASS raster3d modules, r3.univar operates on the cell
44 array defined by the current 3d region settings, not the original
45 extent and resolution of the input map. See g.region.
46 The region setting will not effect the memory consumption of this mod‐
48 ule. The number of subranges in case of value range calculation or the
49 number of equal value groups effect the memory consumption and the cal‐
50 culation time. You can expect a huge time consumption to calculate the
51 equal value groups (flag -e) if you use large region settings + maps
52 which have many equal value groups (> 100000).
53
55 Lausanne FOSS4G 2006 3d demo dataset example
56 The 3d raster map geology has three values. Each value represents a
57 specific geological layer, clay = 1, sand = 2 and bedrock = 3. To cal‐
58 culate the volume of each geological layer, we can use the flag -e to
59 group equal values into single volumes. r3.stats geology -e will pro‐
60 duce the following output:
61 num | value | volume | perc | count
63 1 1.000000 300822000.000 50.13700 50137
64 2 2.000000 101400000.000 16.90000 16900
65 3 3.000000 197778000.000 32.96300 32963
66 4 * 0.000 0.00000 0
67 Number of groups with equal values: 3
68 Sum of non Null cells:
69 Volume = 600000000.000
70 Percentage = 100.000
71 Count = 100000
72 Sum of all cells:
73 Volume = 600000000.000
74 Percentage = 100.000
75 Count = 100000
76 Generic example
79 #create a small 3d region
81 g.region n=1000 s=0 e=2000 w=0 t=300 b=0 res3=100
82 #create a raster3d map with row() and null values
83 r3.mapcalc "volmap = if(row() == 5, null(), row())"
84 #run r3.stats with a subrange of 10
85 r3.stats input=volmap nsteps=10
86 #the result should look like this
87 num | minimum <= value | value < maximum | volume |
88 perc | cell count
89 1 1.000000000 1.900000000 60000000.000
90 10.00000 60
91 2 1.900000000 2.800000000 60000000.000
92 10.00000 60
93 3 2.800000000 3.700000000 60000000.000
94 10.00000 60
95 4 3.700000000 4.600000000 60000000.000
96 10.00000 60
97 5 4.600000000 5.500000000 0.000
98 0.00000 0
99 6 5.500000000 6.400000000 60000000.000
100 10.00000 60
101 7 6.400000000 7.300000000 60000000.000
102 10.00000 60
103 8 7.300000000 8.200000000 60000000.000
104 10.00000 60
105 9 8.200000000 9.100000000 60000000.000
106 10.00000 60
107 10 9.100000000 10.000000001 60000000.000
108 10.00000 60
109 11 * * 60000000.000
110 10.00000 60
111 Sum of non Null cells:
112 Volume = 540000000.000
113 Percentage = 90.000
114 Cell count = 540
115 Sum of all cells:
116 Volume = 600000000.000
117 Percentage = 100.000
118 Cell count = 600
119
122 g.region
123 r3.univar
124 r.stats
125 r.statistics
126 v.univar
127
130 Soeren Gebbert
131 Last changed: $Date: 2007-03-04 01:24:01 +0100 (Sun, 04 Mar 2007) $
133 Full index
135 © 2003-2008 GRASS Development Team
137GRASS 6.3.0 r3.stats(1)