v.to.3d(1)

NAME
v.to.3d - Performs transformation of 2D vector features to 3D.

KEYWORDS
vector, geometry, 3D

SYNOPSIS
v.to.3d
v.to.3d --help
v.to.3d [-rt] input=name [layer=string] [type=string[,string,...]] output=name [column=name] [height=float] [--overwrite] [--help] [--verbose] [--quiet] [--ui]

  Flags:

-r
    Reverse transformation; 3D vector features to 2D

-t
    Do not copy attribute table

--overwrite
    Allow output files to overwrite existing files

--help
    Print usage summary

--verbose
    Verbose module output

--quiet
    Quiet module output

--ui
    Force launching GUI dialog

  Parameters:

input=name [required]
    Name of input vector map
    Or data source for direct OGR access

layer=string
    Layer number or name (’-1’ for all layers)
    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.
    Default: 1

type=string[,string,...]
    Input feature type
    Options: point, line, boundary, centroid
    Default: point,line,boundary,centroid

output=name [required]
    Name for output vector map

column=name
    Name of attribute column used for height
    Can be used for reverse transformation, to store height of points

height=float
    Fixed height for 3D vector features

DESCRIPTION
The v.to.3d module is used to transform 2D vector features to 3D. Height (z-coordinate) of 3D vector features can be specified by height parameter as fixed value or by column parameter.

Flag -r enables to perform reverse transformation, i.e., transform 3D vector to 2D by omitting z-coordinate. Height of input 3D features can be optionally stored in column.

NOTES
When transforming 2D vector features to 3D based on attribute, all NULL values are silently converted to height 0.0.

Reverse transformation is possible for points and lines. In case of lines, the reverse transformation should be used only when all vertices of a line have the same z-coordinate (for example contours).

EXAMPLES

  Transform 2D vector features to 3D

# convert z-values from string to double
v.db.addcolumn map=geodetic_pts columns="Z_VALUE_D double precision"
v.db.update map=geodetic_pts column=Z_VALUE_D qcolumn=Z_VALUE
v.db.select map=geodetic_pts columns=cat,Z_VALUE,Z_VALUE_D
# convert 2D vector point map to 3D based on attribute
v.to.3d input=geodetic_pts out=geodetic_pts_3d column=Z_VALUE_D

  Transform 3D vector features to 2D

v.to.3d -rt input=elev_lid792_bepts output=elev_lid_2d

SEE ALSO
v.transform, v.extrude, v.drape

AUTHOR
Martin Landa, Czech Technical University in Prague, Czech Republic

SOURCE CODE

Available at: v.to.3d source code (history)

Accessed: Sunday Jun 28 03:49:46 2026

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