.\" %W% %G%
.TH filtermap 1
.SH NAME
filtermap \- generate filtered map layer
.br
.I (GRASS-GRID Tool)
.SH SYNOPSIS
.nf
filtermap
.fi
.SH DESCRIPTION
Filtermap
generates an output layer from the input layer by filtering
the data. Input is interactive.  The user enters input map
name, output map name, and the desired number of filter
iterations.  The filtering is done on 3x3 neighborhoods,
with the following weighted average:
.NF
1 2 1
2 4 2  /  16
1 2 1
.FI
The filtering is done only on the input values, not on rows
already averaged during the filtering process.
.SH NOTES
filtermap works properly with supercell layers.
The current window setting is ignored.  Instead,
the window of the input map layer is used.

.SH "AUTHOR"
Marjorie Larson, U.S. Army Construction Engineering Research Laboratory
.br
Larry Band, Dept. of Geography, University of Toronto
