NAME
r.contour - Produces a GRASS binary vector map of
specified contours from GRASS raster map layer.
(GRASS Raster Program)
SYNOPSIS
r.contour
r.contour help
r.contour
input=name output=name
[levels=value,value,...,value]
[minlevel=value]
[maxlevel=value]
[step=value]
DESCRIPTION
r.contour produces a contour map of user-specified
levels from a raster map layer. This program works two
ways:
- Contours are produced from a user-specified list of levels.
- Contours are produced at some regular increment from
user-specified minimum level to maximum level. If no
minimum or maximum level is specified, minimum or maximum
data value will be used.
OPTIONS
Parameters:
- input=name
- Name of input raster map layer.
- output=name
- Name of the binary vector file created.
- levels=value,value,...,value
- Comma separated list of desired levels.
- minlevel=value
- Beginning (lowest) value to be used when stepping
through contours. Default is minimum data value.
- maxlevel=value
- Ending (highest) value to be used when stepping through
contours. Default is maximum data value.
- step=value
- Increment between contour levels.
r.contour may be run interactively or
non-interactively. To run the program non-interactively,
the user must specify the input and output file names,
either a list of levels or a step value and, optionally,
minimum and maximum levels:
-
r.contour
input=name output=name
[levels=value,value,...,value]
[minlevel=value]
[maxlevel=value]
[step=value]
To run the program interactively, the user may simply type
r.contour at the command line and will be prompted
for parameter values.
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.
Currently, 0 is treated as a valid data value by
r.contour.
If a contour level exactly matches a category value in the
raster file, the contour line may backtrack on itself,
causing illegal arcs to be produced in the output GRASS
vector file.
AUTHOR
Terry Baker, U.S. Army Construction Engineering
Research Laboratory