.TH v.extrude 1grass "" "GRASS 7.8.5" "GRASS GIS User's Manual"
.SH NAME
\fI\fBv.extrude\fR\fR  \- Extrudes flat vector features to 3D vector features with defined height.
.br
Optionally the height can be derived from sampling of elevation raster map.
.SH KEYWORDS
vector, geometry, sampling, 3D
.SH SYNOPSIS
\fBv.extrude\fR
.br
\fBv.extrude \-\-help\fR
.br
\fBv.extrude\fR [\-\fBt\fR] \fBinput\fR=\fIname\fR  [\fBlayer\fR=\fIstring\fR]   [\fBcats\fR=\fIrange\fR]   [\fBwhere\fR=\fIsql_query\fR]   [\fBtype\fR=\fIstring\fR[,\fIstring\fR,...]]  \fBoutput\fR=\fIname\fR  [\fBzshift\fR=\fIfloat\fR]   [\fBheight\fR=\fIfloat\fR]   [\fBheight_column\fR=\fIname\fR]   [\fBelevation\fR=\fIname\fR]   [\fBmethod\fR=\fIstring\fR]   [\fBscale\fR=\fIfloat\fR]   [\fBnull_value\fR=\fIfloat\fR]   [\-\-\fBoverwrite\fR]  [\-\-\fBhelp\fR]  [\-\-\fBverbose\fR]  [\-\-\fBquiet\fR]  [\-\-\fBui\fR]
.SS Flags:
.IP "\fB\-t\fR" 4m
.br
Trace elevation
.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\fR \fB[required]\fR" 4m
.br
Name of input vector map
.br
Or data source for direct OGR access
.IP "\fBlayer\fR=\fIstring\fR" 4m
.br
Layer number or name (\(cq\-1\(cq for all layers)
.br
A single vector map can be connected to multiple database tables. This number determines which table to use. When used with direct OGR access this is the layer name.
.br
Default: \fI\-1\fR
.IP "\fBcats\fR=\fIrange\fR" 4m
.br
Category values
.br
Example: 1,3,7\-9,13
.IP "\fBwhere\fR=\fIsql_query\fR" 4m
.br
WHERE conditions of SQL statement without \(cqwhere\(cq keyword
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Example: income < 1000 and population >= 10000
.IP "\fBtype\fR=\fIstring[,\fIstring\fR,...]\fR" 4m
.br
Input feature type
.br
Options: \fIpoint, line, area\fR
.br
Default: \fIpoint,line,area\fR
.IP "\fBoutput\fR=\fIname\fR \fB[required]\fR" 4m
.br
Name for output vector map
.IP "\fBzshift\fR=\fIfloat\fR" 4m
.br
Shifting value for z coordinates
.br
Default: \fI0\fR
.IP "\fBheight\fR=\fIfloat\fR" 4m
.br
Fixed height for 3D vector features
.IP "\fBheight_column\fR=\fIname\fR" 4m
.br
Name of attribute column with feature height
.IP "\fBelevation\fR=\fIname\fR" 4m
.br
Elevation raster map for height extraction
.IP "\fBmethod\fR=\fIstring\fR" 4m
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Sampling interpolation method
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Options: \fInearest, bilinear, bicubic\fR
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Default: \fInearest\fR
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\fBnearest\fR: Nearest\-neighbor interpolation
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\fBbilinear\fR: Bilinear interpolation
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\fBbicubic\fR: Bicubic interpolation
.IP "\fBscale\fR=\fIfloat\fR" 4m
.br
Scale factor sampled raster values
.br
Default: \fI1.0\fR
.IP "\fBnull_value\fR=\fIfloat\fR" 4m
.br
Height for sampled raster NULL values
.SH DESCRIPTION
\fIv.extrude\fR creates faces, kernels or 3D lines based on input
2D vector features. Points are converted to 3D vertical lines, lines
to faces and areas to volumes (composition of closed set of faces and
kernel).
.PP
If \fBelevation\fR parameter is used then 3D vector features follow
the elevation model by using individual elevation values for the
vertices. Height for vertices is interpolated from elevation raster
map using given interpolation \fBmethod\fR.
.SH NOTES
\fIv.extrude\fR extrudes vector features which means that points
are converted to vertical lines. Lines and area boundaries are
extruded to a set of faces, each segment defines one face. Area
centroids are written as kernels. Area as a composition of boundaries
and centroid is stored as a closed set of faces and kernel which
define a volume.
.PP
For conversion of 2D points or lines to 3D can be
used \fIv.to.3d\fR
or \fIv.drape\fR. In opposite
to \fIv.extrude\fR, these modules do not extrude vector features,
they defines z\-coordinate for the features from given parameters or by
sampling elevation raster map values. It means that no feature type
conversion is applied, points remain still points in the output vector
map. Same applies for the lines.
.PP
\fIv.extrude\fR modifies only features geometry. Feature categories
remain untouched and attribute data is copied from input vector map to
the output.
.PP
By default, all features (including features without category) from
input vector map are processed (\fBlayer=\-1\fR). Feature selection
can be applied by \fBlayer\fR, \fBcats\fR or \fBwhere\fR
parameter.
.SH EXAMPLES
.SS 3D houses with fixed height
.br
.nf
\fC
v.extrude input=houses output=houses3D height=5 type=area
\fR
.fi
.SS 3D houses with individual height
.br
.nf
\fC
v.extrude input=houses output=houses3D elevation=dem height_column=height type=area
\fR
.fi
.SS Convert 2D points to 3D vertical lines with fixed height
.br
.nf
\fC
v.extrude input=geodetic_pts output=points3D height=200 type=point
\fR
.fi
.SH SEE ALSO
\fI
v.transform,
v.drape,
v.to.3d
\fR
.PP
\fI
wxGUI 3D viewer
\fR
.SH AUTHORS
Jachym Cepicky,
.br
Updated for GRASS 7 by Martin Landa, FBK\-irst,
Italy and Czech Technical University in Prague, Czech Republic
.SH SOURCE CODE
.PP
Available at: v.extrude source code (history)
.PP
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.PP
© 2003\-2020
GRASS Development Team,
GRASS GIS 7.8.5 Reference Manual