.\" %W% %G%
.TH thin 1
.SH NAME
thin \- generate stream network map layer
.br
.I (GRASS-GRID Tool)
.SH SYNOPSIS
.nf
thin
.fi
.SH DESCRIPTION
Thin
generates a stream network map layer from a drainage
accumulation input layer.  Input is interactive.
User supplies an accumulation
threshold, as well as the desired number of thinning
iterations.  The accumulation threshold will determine
the detail of the tributaries in the resulting stream
network.  (The smaller the threshold, the more detail
in the result.)  All cells within the watershed which have
category values less than the threshold will be eliminated.
If the resulting stream network is to be used in the rest
of the watershed software series (for programs "clcode"
and "catch"), then it is essential the thinning be done
to one pixel wide.  This may require a high number of
thinning iterations.
.SH NOTES
thin works properly with supercell layers.
The current window setting is ignored.  Instead,
the window of the input map layer is used.

.SH SEE ALSO
river[1]

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