.TH r.carve 1grass "" "GRASS 7.8.5" "GRASS GIS User's Manual"
.SH NAME
\fI\fBr.carve\fR\fR  \- Generates stream channels.
.br
Takes vector stream data, transforms it to raster and subtracts depth from the output DEM.
.SH KEYWORDS
raster, hydrology
.SH SYNOPSIS
\fBr.carve\fR
.br
\fBr.carve \-\-help\fR
.br
\fBr.carve\fR [\-\fBn\fR] \fBraster\fR=\fIname\fR \fBvector\fR=\fIname\fR \fBoutput\fR=\fIname\fR  [\fBpoints\fR=\fIname\fR]   [\fBwidth\fR=\fIfloat\fR]   [\fBdepth\fR=\fIfloat\fR]   [\-\-\fBoverwrite\fR]  [\-\-\fBhelp\fR]  [\-\-\fBverbose\fR]  [\-\-\fBquiet\fR]  [\-\-\fBui\fR]
.SS Flags:
.IP "\fB\-n\fR" 4m
.br
No flat areas allowed in flow direction
.IP "\fB\-\-overwrite\fR" 4m
.br
Allow output files to overwrite existing files
.IP "\fB\-\-help\fR" 4m
.br
Print usage summary
.IP "\fB\-\-verbose\fR" 4m
.br
Verbose module output
.IP "\fB\-\-quiet\fR" 4m
.br
Quiet module output
.IP "\fB\-\-ui\fR" 4m
.br
Force launching GUI dialog
.SS Parameters:
.IP "\fBraster\fR=\fIname\fR \fB[required]\fR" 4m
.br
Name of input raster elevation map
.IP "\fBvector\fR=\fIname\fR \fB[required]\fR" 4m
.br
Name of input vector map containing stream(s)
.br
Or data source for direct OGR access
.IP "\fBoutput\fR=\fIname\fR \fB[required]\fR" 4m
.br
Name for output raster map
.IP "\fBpoints\fR=\fIname\fR" 4m
.br
Name for output vector map for adjusted stream points
.IP "\fBwidth\fR=\fIfloat\fR" 4m
.br
Stream width (in meters)
.br
Default is raster cell width
.IP "\fBdepth\fR=\fIfloat\fR" 4m
.br
Additional stream depth (in meters)
.SH DESCRIPTION
\fIr.carve\fR accepts vector stream data as input, transforms them to
raster, and subtracts a default\-depth + additional\-depth from a DEM. If
the given width is more than 1 cell, it will carve the stream with the
given width. With the \fB\-n\fR flag it should eliminate all flat cells within
the stream, so when and if the water gets into the stream it will
flow. The \fIpoints\fR option generates x,y,z for points which define the stream
with the z\-value of the bottom of the carved\-in stream. These points
can then be combined with contours to interpolate a new DEM with
better representation of valleys.
.SH NOTES
\fIr.carve\fR does not create a depressionless DEM because many
depressions are in flat areas and not in the streams.
.SH EXAMPLE
North Carolina sample dataset:
.br
.nf
\fC
# set computational region
g.region raster=elev_lid792_1m \-p
# digitize a ditch for the farm pond
echo \(dqL  3 1
 638692.93595422 220198.90026383
 638737.42270627 220149.74706926
 638984.43306379 220148.19158842
 1     1\(dq | v.in.ascii \-n input=\- output=ditch format=standard
# visualize original data
d.mon wx0
d.rast elev_lid792_1m
d.vect ditch
# carve
r.carve raster=elev_lid792_1m vector=ditch output=carved_dem width=3 depth=0.5
# visualize resulting carved DEM map
d.rast carved_dem
# visualize
r.relief input=elev_lid792_1m output=elev_lid792_1m_shaded
r.relief input=carved_dem output=carved_dem_shaded
d.rast elev_lid792_1m_shaded
d.erase
d.rast carved_dem_shaded
# flow accumulation
r.watershed elevation=elev_lid792_1m accumulation=elev_lid792_1m_accum
r.watershed elevation=carved_dem accumulation=carved_dem_accum
d.rast elev_lid792_1m_accum
d.erase
d.rast carved_dem_accum
# differences
r.mapcalc \(dqaccum_diff = elev_lid792_1m_accum \- carved_dem_accum\(dq
r.colors accum_diff color=differences
d.erase
d.rast accum_diff
\fR
.fi
.TS
expand;
lw60 lw1 lw60.
T{
\fIFig: Original 1m LiDAR based DEM with vector streams map on top\fR
T}	 	T{
\fIFig: Original 1m LiDAR based DEM shown as shaded terrain\fR
T}
.sp 1
T{
\fIFig: Carved 1m LiDAR based DEM\fR
T}	 	T{
\fIFig: Carved 1m LiDAR based DEM shown as shaded terrain\fR
T}
.sp 1
T{
\fIFig: Flow accumulation in original 1m LiDAR based DEM\fR
T}	 	T{
\fIFig: Flow accumulation in carved 1m LiDAR based DEM\fR
T}
.sp 1
.TE
.SH KNOWN ISSUES
The module does not operate yet in latitude\-longitude locations.  It
has not been thoroughly tested, so not all options may work properly \-
but this was the intention.
.SH REFERENCES
Terrain
modeling and Soil Erosion Simulations for Fort Hood and Fort Polk test
areas, by Helena Mitasova, Lubos Mitas, William M. Brown, Douglas
M.  Johnston, GMSL (Report for CERL 1999)
.SH SEE ALSO
\fI
r.flow,
r.fill.dir,
r.watershed
\fR
.SH AUTHOR
Bill Brown (GMSL)
.br
GRASS 6 update: Brad Douglas
.SH SOURCE CODE
.PP
Available at: r.carve source code (history)
.PP
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.PP
© 2003\-2020
GRASS Development Team,
GRASS GIS 7.8.5 Reference Manual