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 [-fq] data=string [clump=string] [centroids=string]
17 [--overwrite]
18 Flags:
20 -f Generate unformatted report
21 -q Run quietly
23 --overwrite
25 Parameters:
27 data=string
28 Existing raster map representing data that will be summed within
29 clumps
30 clump=string
32 Existing raster map, preferably the output of r.clump
33 centroids=string
35 Vector points map to contain clump centroids
36
38 r.volume is a tool for summing cell values within clumps and calculat‐
39 ing volumes and centroids of patches or clumps.
40 r.volume generates a table containing the sum of all cells from a
42 data_map layer sorted by category on a clump map, and optionally gener‐
43 ates a vector points map of the centroids for each clump. If a clump
44 map is not specified, the current MASK is used. The sum is multiplied
45 by the area of a cell to give the volume occupied by that cell. See
46 below for an example of the output table. The table is placed in the
47 user's home directory in the file Gvol.report. (or not???)
48
50 If a clump map is not given and a MASK not set, the program exits with
51 an error message.
52 r.volume works in the current window and respects the current MASK.
54
56 The following report was generated by the command: (spearfish data
57 base; fields.only is fields layer without the National Forest category)
58 r.volume d=elevation c=fields.only centr=field.centers
60 Volume report on data from elevation using clumps on fields.only map
63 Cat Average Data # Cells Centroid Total
64 Number in clump Total in clump Easting Northing Volume
65 1 1181.09 75590 64 595500.00 4927700.00 755900000.00
66 2 1163.50 69810 60 597100.00 4927700.00 698100000.00
67 3 1146.83 34405 30 598300.00 4927700.00 344050000.00
68 4 1193.20 366311 307 599400.00 4927300.00 3663110000.00
69 .....
70 .....
71 .....
72 60 1260.08 351563 279 603100.00 4921000.00 3515630000.00
73 61 1213.93 35204 29 603700.00 4921500.00 352040000.00
74 62 1207.71 33816 28 604100.00 4921500.00 338160000.00
75 Total Volume = 67226740000.00
76 The Data Total column is the sum of the elevations for each in each of
77 the fields. The Total Volume is the sum multiplied by the e-w resolu‐
78 tion times the n-s resolution. Note that the units on the volume may
79 be difficult if the units of cell values on the data_map layer and the
80 resolution units differ.
81 CENTROIDS
83 The centroid coordinates are the same as those stored in the sites file
84 (if one was requested). They are guaranteed to fall on a cell of the
85 appropriate category, thus they are not always the true, mathematical
86 centroid. They will always fall at a cell center.
87 FORMAT OF CENTROIDS table
89 For each line of above table the vector points table contains these
90 columns: easting, northing, cat, volume, average, sum, count
91 This can be converted directly to a raster map with each point a sepa‐
93 rate category using v.to.rast.
94 APPLICATIONS
96 By preprocessing the elevation layer with r.mapcalc and using suitable
97 masking or clump maps, very interesting applications can be done with
98 r.volume. Such as, calculating the volume of rock in a potential
99 quarry; calculating cut/fill volumes for roads; finding water volumes
100 in potential reservoirs. Data layers of other measures of real values.
101
103 Dr. James Hinthorne, Central Washington University GIS Laboratory
104 December 1988.
105 Full index
107GRASS 6.2.2 r.volume(1)