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


vector, geometry, 3D

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


Reverse transformation; 3D vector features to 2D

Do not copy attribute table

Allow output files to overwrite existing files

Print usage summary

Verbose module output

Quiet module output

Force launching GUI dialog


Name of input vector map
Or data source for direct OGR access

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

Input feature type
Options: point, line, boundary, centroid
Default: point,line,boundary,centroid

Name for output vector map

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

Fixed height for 3D vector features


The 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.


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).


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 map=geodetic_pts columns=cat,Z_VALUE,Z_VALUE_D
# convert 2D vector point map to 3D based on attribute input=geodetic_pts out=geodetic_pts_3d column=Z_VALUE_D

Transform 3D vector features to 2D -rt input=elev_lid792_bepts output=elev_lid_2d


v.transform, v.extrude, v.drape


Martin Landa, Czech Technical University in Prague, Czech Republic


Available at: source code (history)

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GRASS 7.8.5