1r.volume(1) Grass User's Manual r.volume(1)
2
6 r.volume - Calculates the volume of data "clumps", and (optionally)
7 produces a GRASS vector points map containing the calculated centroids
8 of these clumps.
9
11 raster
12
14 r.volume
15 r.volume help
16 r.volume [-f] data=string [clump=string] [centroids=string]
17 [--overwrite] [--verbose] [--quiet]
18 Flags:
20 -f
21 Generate unformatted report
22 --overwrite
24 Allow output files to overwrite existing files
25 --verbose
27 Verbose module output
28 --quiet
30 Quiet module output
31 Parameters:
33 data=string
34 Existing raster map representing data that will be summed within
35 clumps
36 clump=string
38 Existing raster map, preferably the output of r.clump
39 centroids=string
41 Vector points map to contain clump centroids
42
44 r.volume is a tool for summing cell values within clumps and calculat‐
45 ing volumes and centroids of patches or clumps.
46 r.volume generates a table containing the sum of all cells from a
48 data_map layer sorted by category on a clump map, and optionally gener‐
49 ates a vector points map of the centroids for each clump. If a clump
50 map is not specified, the current MASK is used. The sum is multiplied
51 by the area of a cell to give the volume occupied by that cell. See
52 below for an example of the output table.
53
55 If a clump map is not given and a MASK not set, the program exits with
56 an error message.
57 r.volume works in the current region and respects the current MASK.
59
61 The following report was generated by the command: (spearfish data
62 base; fields.only is the fields layer without the National Forest cate‐
63 gory)
64 r.volume data=elevation clump=fields.only centroids=field.centers
66 Volume report on data from elevation using clumps on fields.only map
69 Cat Average Data # Cells Centroid Total
70 Number in clump Total in clump Easting Northing Volume
71 1 1181.09 75590 64 595500.00 4927700.00 755900000.00
72 2 1163.50 69810 60 597100.00 4927700.00 698100000.00
73 3 1146.83 34405 30 598300.00 4927700.00 344050000.00
74 4 1193.20 366311 307 599400.00 4927300.00 3663110000.00
75 .....
76 .....
77 .....
78 60 1260.08 351563 279 603100.00 4921000.00 3515630000.00
79 61 1213.93 35204 29 603700.00 4921500.00 352040000.00
80 62 1207.71 33816 28 604100.00 4921500.00 338160000.00
81 Total Volume = 67226740000.00
82 The Data Total column is the sum of the elevations for each in each of
83 the fields. The Total Volume is the sum multiplied by the e-w resolu‐
84 tion times the n-s resolution. Note that the units on the volume may
85 be difficult if the units of cell values on the data_map layer and the
86 resolution units differ.
87 CENTROIDS
89 The centroid coordinates are the same as those stored in the sites file
90 (if one was requested). They are guaranteed to fall on a cell of the
91 appropriate category, thus they are not always the true, mathematical
92 centroid. They will always fall at a cell center.
93 FORMAT OF CENTROIDS table
95 For each line of above table the vector points table contains these
96 columns: easting, northing, cat, volume, average, sum, count
97 This can be converted directly to a raster map with each point a sepa‐
99 rate category using v.to.rast.
100 APPLICATIONS
102 By preprocessing the elevation layer with r.mapcalc and using suitable
103 masking or clump maps, very interesting applications can be done with
104 r.volume. Such as, calculating the volume of rock in a potential
105 quarry; calculating cut/fill volumes for roads; finding water volumes
106 in potential reservoirs. Data layers of other measures of real values.
107
109 Dr. James Hinthorne, Central Washington University GIS Laboratory
110 December 1988.
111 Full index
113 © 2003-2008 GRASS Development Team
115GRASS 6.3.0 r.volume(1)