r.circle

## 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]

### Flags:

-b
  Generate binary raster map
--overwrite
  Force overwrite of output files

### 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
  Multiplier

## DESCRIPTION

This module creates a raster map containing concentric rings around a given point. The cell values are increasing linear from the center point to outer rings. Minimum and maximum radius can be selected. Optionally a "donut" ring can be created to use as (binary) filter for i.ifft inverse Fourier transform (apply filter with r.mask).

## EXAMPLES

Generate a circle at current map center with a radius of 300m:

          EASTCENTER=`g.region -c |  awk ' /region center easting:/ { print $4 }'`
          NORTHCENTER=`g.region -c | awk ' /region center northing:/ { print $4 }'`
          r.circle -b out=circle coordinate=$EASTCENTER,$NORTHCENTER max=300

## SEE ALSO

g.remove, g.rename, i.fft, i.ifft

## AUTHOR

Bill Brown, U.S. Army Construction Engineering Research Laboratory
Additional flag/min/max parameter by Markus Neteler, University of Hannover

Last changed: $Date: 2006/04/13 19:01:37 $

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