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NAME
r.circle - Creates a raster map containing concentric rings around a given point.
KEYWORDS
raster
SYNOPSIS
r.circle
r.circle help
r.circle [-b] output=name coordinate=x,y [min=float] [max=float] [mult=float] [--overwrite] [--verbose] [--quiet]
Flags:
- -b
- Generate binary raster map
- --overwrite
- Allow output files to overwrite existing files
- --verbose
- Verbose module output
- --quiet
- Quiet module output
Parameters:
- output=name
- Name for output raster map
- coordinate=x,y
- The coordinate of the center (east,north)
- min=float
- Minimum radius for ring/circle map (in meters)
- max=float
- Maximum radius for ring/circle map (in meters)
- mult=float
- Data value multiplier
DESCRIPTION
This module creates an output raster map centered on the x,y values specified
with the coordinate parameter, out to the edge of the current region.
The output cell values increase linearly from the specified center. The min
and max parameters control the inner and outer output raster map radii, respectively.
The mult parameter can be used to multiply the output raster cells by a common factor.
Note that this parameter does not affect the output raster position or size; only the z-values
are changed with this parameter.
Binary-output raster maps (solid circles of one value) can be created
with the -b flag. Raster maps so created can be used to create
binary filters for use in i.ifft (inverse Fourier transformations;
apply filter with r.mask).
EXAMPLES
Generate a raster circle at current map center with a radius of 300m and outwardly
increasing raster values:
EASTCENTER=`g.region -c | awk ' /center easting:/ { print $3 }'`
NORTHCENTER=`g.region -c | awk ' /center northing:/ { print $3 }'`
r.circle output=circle coordinate=${EASTCENTER},${NORTHCENTER} max=300
Generate a binary raster ring around current map center with an inner radius
of 500m and an outer radius of 1000m:
EASTCENTER=`g.region -c | awk ' /center easting:/ { print $3 }'`
NORTHCENTER=`g.region -c | awk ' /center northing:/ { print $3 }'`
r.circle -b output=circle coordinate=${EASTCENTER},${NORTHCENTER} min=500 max=1000
SEE ALSO
g.region,
g.remove,
g.rename,
i.fft,
i.ifft,
r.mask
AUTHOR
Bill Brown, U.S. Army Construction Engineering Research Laboratory
Additional flag/min/max parameter by Markus Neteler, University of Hannover
Last changed: $Date: 2009-01-05 14:11:47 -0800 (Mon, 05 Jan 2009) $
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