.TH r.buildvrt 1grass "" "GRASS 7.8.5" "GRASS GIS User's Manual"
.SH NAME
\fI\fBr.buildvrt\fR\fR  \- Build a VRT (Virtual Raster) from the list of input raster maps.
.SH KEYWORDS
raster, mosaic, virtual raster
.SH SYNOPSIS
\fBr.buildvrt\fR
.br
\fBr.buildvrt \-\-help\fR
.br
\fBr.buildvrt\fR  [\fBinput\fR=\fIname\fR[,\fIname\fR,...]]   [\fBfile\fR=\fIname\fR]  \fBoutput\fR=\fIname\fR  [\fBtitle\fR=\fIphrase\fR]   [\-\-\fBoverwrite\fR]  [\-\-\fBhelp\fR]  [\-\-\fBverbose\fR]  [\-\-\fBquiet\fR]  [\-\-\fBui\fR]
.SS Flags:
.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 "\fBinput\fR=\fIname[,\fIname\fR,...]\fR" 4m
.br
Name of input raster files
.IP "\fBfile\fR=\fIname\fR" 4m
.br
Input file with one raster map name per line
.IP "\fBoutput\fR=\fIname\fR \fB[required]\fR" 4m
.br
Name for output raster map
.IP "\fBtitle\fR=\fIphrase\fR" 4m
.br
Title for resultant raster map
.SH DESCRIPTION
\fIr.buildvrt\fR builds a virtual raster (VRT) that is a mosaic of
the list of input raster maps. The purpose of such a VRT is to provide
fast access to small subsets of the VRT, also with multiple simultaneous
read requests.
.SH NOTES
\fIr.buildvrt\fR creates a list of raster maps that can be
located in different mapsets. The output is a read\-only link to
the original raster maps which is only valid if the original raster
maps remain in the originally indicated mapset. A VRT can also be built
from raster maps registered with \fIr.external\fR.
.PP
Reading the whole VRT is slower than reading the equivalent single
raster map. Only reading small parts of the VRT provides a performance
benefit.
.PP
A GRASS virtual raster can be regarded as a simplified version of GDAL\(cqs
virtual raster format.
The GRASS equivalent is simpler because issues like nodata, projection,
resolution, resampling, masking are already handled by native GRASS
raster routines.
.SH EXAMPLES
.SS VRT from a DEM in the North Carolina sample dataset
In this exercise a low resolution DEM is resampled to a high
resolution DEM. This is subsequently cut into small tiles and
from that a virtual tile mosaik is created:
.br
.nf
\fC
# set the computational region to elevation map
g.region raster=elev_state_500m \-p
# enforce higher resolution
g.region res=50 \-p
# resample the 500 meter DEM to 50 meter resolution
r.resamp.interp input=elev_state_500m output=elev_state_50m method=bilinear
# create tiles from resulting large 50 m elevation map
r.tile input=elev_state_50m output=elev_state_50m_tile_ width=1000 height=1000 overlap=0
# for convenience, dump list of tile names to a file
g.list type=raster pattern=elev_state_50m_tile_* output=tilelist.csv
# build a mosaik as VRT from tile list
r.buildvrt file=tilelist.csv output=elev_state_50m_vrt
\fR
.fi
.SH SEE ALSO
\fI
r.tile,
r.patch,
r.external
\fR
.PP
The equivalent GDAL utility
\fI
gdalbuildvrt
\fR
.SH AUTHOR
Markus Metz
.br
Sponsored by mundialis
.SH SOURCE CODE
.PP
Available at: r.buildvrt source code (history)
.PP
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.PP
© 2003\-2020
GRASS Development Team,
GRASS GIS 7.8.5 Reference Manual