Flags:

-t

Shift all z values to bottom=0

-w

Swap coordinates x, y and then apply other parameters

-x

Swap coordinates x, z and then apply other parameters

-y

Swap coordinates y, z and then apply other parameters

-a

Swap coordinates after the other transformations

-b

Do not build topology

--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

output=name [required]

Name for output vector map

xshift=float

Shifting value for x coordinates
Default: 0.0

yshift=float

Shifting value for y coordinates
Default: 0.0

zshift=float

Shifting value for z coordinates
Default: 0.0

xscale=float

Scaling factor for x coordinates
Default: 1.0

yscale=float

Scaling factor for y coordinates
Default: 1.0

zscale=float

Scaling factor for z coordinates
Default: 1.0

zrotation=float

Rotation around z axis in degrees (counter-clockwise)
Default: 0.0

columns=name[,name,...]

Name of attribute column(s) used as transformation parameters
Format: parameter:column, e.g. xshift:xs,yshift:ys,zrot:zr

DXF/DWG drawings

Most DXF/DWG drawings are done within XY coordinate space. To transform them to a national grid, we can use v.transform together with v.rectify and a first-order transformation.

v.transform -t in=watertowerXY out=watertower_z zscale=0.04 zshift=1320
v.rectify in=watertower_z out=watertowerUTM points=wt.points order=1

Extrude 2D vector points to 3D based on attribute column values

Spearfish example with manual table editing for vertical shift:

# work on own map copy:
g.copy vect=archsites@PERMANENT,myarchsites
# add new ’zs’ column to later store height of each site:
v.db.addcolumn myarchsites col="zs double precision"
v.db.update myarchsites layer=1 column=zs value="cat * 1000"
# perform z transformation:
v.transform -t input=archsites output=myarchsites3d column="zshift:zs" table="archsites_t"
# drop table containing transformation parameters:
echo "drop table archsites_t" | db.execute

The resulting map is a 3D vector map.

Extrude 2D vector points to 3D based on attribute column values

Spearfish example with automated elevation extraction for vertical shift:

# work on own map copy:
g.copy vect=archsites@PERMANENT,myarchsites
# add new ’zs’ column to later store height of each site:
v.db.addcolumn myarchsites col="zs double precision"
# set region to elevation map and fetch individual heights:
g.region raster=elevation.10m -p
v.what.rast myarchsites rast=elevation.10m col=zs
# verify:
v.db.select myarchsites
# perform transformation to 3D
v.transform -t myarchsites output=myarchsites3d column="zshift:zs" layer=1
# drop table containing transformation parameters
v.db.dropcolumn myarchsites3d col=zs

The resulting map is a 3D vector map.