NAME¶
r.contour - Produces a vector map of specified contours from a
raster map.
KEYWORDS¶
raster, DEM, contours, vector
SYNOPSIS¶
r.contour
r.contour help
r.contour [-
qn]
input=
name output=
name
[
levels=
float[,
float,...]]
[
minlevel=
float] [
maxlevel=
float]
[
step=
float] [
cut=
integer] [--
overwrite]
[--
verbose] [--
quiet]
Flags:¶
- -q
-
Run quietly
- -n
-
Suppress single crossing error messages
- --overwrite
-
Allow output files to overwrite existing files
- --verbose
-
Verbose module output
- --quiet
-
Quiet module output
Parameters:¶
- input=name
-
Name of input raster map
- output=name
-
Name for output vector map
- levels=float[,float,...]
-
List of contour levels
- minlevel=float
-
Minimum contour level
- maxlevel=float
-
Maximum contour level
- step=float
-
Increment between contour levels
- cut=integer
-
Minimum number of points for a contour line (0 -> no limit)
Default: 0
DESCRIPTION¶
r.contour produces a GRASS binary vector map of specified contours from a
GRASS raster map. Contours can be produced using a comma-separated list of
values in
levels, or at some regular increment using the
step
parameter, using
minlevel and
maxlevel as minimum and maximum
contour values, respectively. If no
minlevel or
maxlevel is
specified, the minimum and maximum cell values in the
input raster map
will be used.
NOTES¶
r.contour will either step through incremental contours or produce
contours from a list of levels, not both. If both a list of levels and a step
are specified, the list will be produced and the step will be ignored.
Zero is treated as a valid data value by
r.contour.
If a contour level exactly matches a category value in the raster map, the
contour line may backtrack on itself, causing illegal arcs to be produced in
the output GRASS vector map.
The optional
cut parameter allows the user to specify a minimum number of
raster cells eligilble to be included in a contour line written to the
output vector map. It acts like a filter, omitting spurs, single
points, etc., making the output more generalized.
EXAMPLE¶
In the Spearfish location, produce a vector contour map from input raster
elevation.dem with contour levels from 1000m to 2000m, 100m contour
step, and a minimum of 200 input raster points contributing to the contour
line: r.contour input=elevation.dem output=elevation_dem_contours
minlevel=1000 maxlevel=2000 step=100 cut=200
AUTHORS¶
Terry Baker, U.S. Army Construction Engineering Research Laboratory
3/2001: cut parameter and fixes by Andrea Aime (aaime@libero.it)
Last changed: $Date: 2008-05-16 21:09:06 +0200 (Fri, 16 May 2008) $
Full index
© 2003-2014 GRASS Development Team