NAME
r.median - Finds the median of values in a cover map within
areas assigned the same category value in a user-specified base map.
(GRASS Raster Program)
SYNOPSIS
r.median
r.median help
r.median base=name
cover=name output=name
DESCRIPTION
r.median calculates the median category of data
contained in a cover raster map layer for areas
assigned the same category value in the user-specified
base raster map layer. These median values are
stored in the new output map layer.
The output map is actually a reclass of the base map.
OPTIONS
If the user simply types r.median on the command line, the
user is prompted for the parameter values
through the standard
parser interface.
Alternately, the user can supply all needed parameter values
on the command line.
Parameters:
- base=name
- An existing raster map layer in the user's current
mapset search path. For each group of cells assigned the
same category value in the base map, the median of
the values assigned these cells in the cover map
will be computed.
- cover=name
- An existing raster map layer containing the values
to be used to compute the median within each category of the base map.
- output=name
- The name of a new map layer to contain program output
(a reclass of the base map). The median values will be stored
in the output map.
NOTES
The user should use the results of r.median with
care. Since this utility assigns a value to each cell
which is based on global information (i.e., information at
spatial locations other than just the location of the cell
itself), the resultant map layer is only valid if the
geographic region and mask settings are the same as they
were at the time that the result map was created.
Results are affected by the current region settings and mask.
SEE ALSO
AUTHOR
Michael Shapiro,
U.S.Army Construction Engineering
Research Laboratory
Last changed: $Date$