Note: A new GRASS GIS stable version has been released: GRASS GIS 7.6, available here.
Updated manual page: here
NAME
r.volume - Calculates the volume of data "clumps".
Optionally produces a GRASS vector points map containing the calculated centroids of these clumps.
KEYWORDS
raster,
volume,
clumps
SYNOPSIS
r.volume
r.volume --help
r.volume [-f] input=name [clump=name] [centroids=name] [output=name] [--overwrite] [--help] [--verbose] [--quiet] [--ui]
Flags:
- -f
- Generate unformatted report (items separated by colon)
- --overwrite
- Allow output files to overwrite existing files
- --help
- Print usage summary
- --verbose
- Verbose module output
- --quiet
- Quiet module output
- --ui
- Force launching GUI dialog
Parameters:
- input=name [required]
- Name of input raster map representing data that will be summed within clumps
- clump=name
- Name of input clump raster map
- Preferably the output of r.clump. If no clump map is given than MASK is used.
- centroids=name
- Name for output vector points map to contain clump centroids
- output=name
- Name for output file to hold the report
- If no output file given report is printed to standard output
r.volume is a tool for summing cell values within clumps and
calculating volumes and centroids of patches or clumps.
r.volume generates a table containing the sum of all cells
from a input raster map sorted by category on a clump
raster map, and optionally generates a vector points map of the
centroids for each clump. If a clump map is not specified, the
current MASK is used. The MASK can be defined
by r.mask. The sum is multiplied by
the area of a cell to give the volume occupied by that cell. See below
for an example of the output table.
If a clump map is not given and a MASK not set, the program exits with
an error message.
r.volume works in the current region and respects the current
MASK.
The centroid coordinates are the same as those stored in the vector
map (if one was requested by
centroids parameter). They are
guaranteed to fall on a cell of the appropriate category, thus they
are not always the true, mathematical centroid. They will always fall
at a cell center.
Attribute table linked to the vector map with centroids contains several columns:
- cat - category value (integer)
- volume - volume value (double precision)
- average - average value in the clump (double precision)
- sum - sum of cell values in the clump (double precision)
- count - number of cells with the category (integer)
Vector points can be converted directly to a raster map with each
point a separate category
using v.to.rast.
By preprocessing the elevation raster map
with
r.mapcalc and using
suitable masking or clump maps, very interesting applications can be
done with
r.volume. Such as, calculating the volume of rock
in a potential quarry; calculating cut/fill volumes for roads; finding
water volumes in potential reservoirs.
The following report was generated by the command (North Carolina dataset):
# set computational region
g.region raster=elevation
# compute volume
r.volume input=elevation clump=geology_30m
Volume report on data from <elevation> using clumps on <geology_30m> raster map
Category Average Data # Cells Centroid Total
Number in clump Total in clump Easting Northing Volume
-----------------------------------------------------------------------------
217 118.93 86288828 725562 635325.00 221535.00 8628882798.63
262 108.97 21650560 198684 638935.00 222495.00 2165056037.02
270 92.23 63578874 689373 642405.00 221485.00 6357887443.53
405 132.96 33732662 253710 631835.00 224095.00 3373266208.59
583 139.35 3011288 21609 630205.00 224665.00 301128821.55
720 124.30 599618 4824 634075.00 227995.00 59961816.06
766 132.43 936791 7074 631425.00 227845.00 93679120.08
862 118.31 7302317 61722 630505.00 218885.00 730231746.74
910 94.20 4235816 44964 639215.00 216365.00 423581613.11
921 135.22 1693985 12528 630755.00 215445.00 169398523.05
945 127.24 1145 9 630015.00 215015.00 114512.03
946 89.91 365748 4068 639085.00 215255.00 36574833.85
948 129.02 112632 873 630185.00 215115.00 11263181.57
-----------------------------------------------------------------------------
Total Volume = 22351026655.81
The
Data Total column is the sum of the elevations for each
in each of the fields. The
Total Volume is the sum
multiplied by the east-west resolution times the north-south
resolution. Note that the units on the volume may be difficult if the
units of cell values on the
input raster map and the resolution
units differ.
r.clump,
r.mask,
r.mapcalc
Dr. James Hinthorne, Central Washington University GIS Laboratory,
December 1988.
Updated to GRASS 7 by Martin Landa, Czech Technical University in Prague, Czech Republic
Last changed: $Date: 2014-12-19 13:17:36 -0800 (Fri, 19 Dec 2014) $
SOURCE CODE
Available at: r.volume source code (history)
Note: A new GRASS GIS stable version has been released: GRASS GIS 7.6, available here.
Updated manual page: here
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© 2003-2019
GRASS Development Team,
GRASS GIS 7.2.4svn Reference Manual