NAME

       v.extrude  - Extrudes flat vector features to 3D vector features with defined height.
       Optionally the height can be derived from sampling of elevation raster map.

KEYWORDS

       vector, geometry, sampling, 3D

SYNOPSIS

       v.extrude
       v.extrude --help
       v.extrude [-t] input=name  [layer=string]   [cats=range]   [where=sql_query]   [type=string[,string,...]]
       output=name  [zshift=float]   [height=float]   [height_column=name]   [elevation=name]    [method=string]
       [scale=float]   [null_value=float]   [--overwrite]  [--help]  [--verbose]  [--quiet]  [--ui]

   Flags:
       -t
           Trace elevation

       --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

       cats=range
           Category values
           Example: 1,3,7-9,13

       where=sql_query
           WHERE conditions of SQL statement without ’where’ keyword
           Example: income < 1000 and population >= 10000

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

       output=name [required]
           Name for output vector map

       zshift=float
           Shifting value for z coordinates
           Default: 0

       height=float
           Fixed height for 3D vector features

       height_column=name
           Name of attribute column with feature height

       elevation=name
           Elevation raster map for height extraction

       method=string
           Sampling interpolation method
           Options: nearest, bilinear, bicubic
           Default: nearest
           nearest: Nearest-neighbor interpolation
           bilinear: Bilinear interpolation
           bicubic: Bicubic interpolation

       scale=float
           Scale factor sampled raster values
           Default: 1.0

       null_value=float
           Height for sampled raster NULL values

DESCRIPTION

       v.extrude 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).

       If  elevation  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 method.

NOTES

       v.extrude  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.

       For conversion of 2D points or lines to 3D can be used v.to.3d or  v.drape.  In  opposite  to  v.extrude,
       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.

       v.extrude  modifies  only  features  geometry.  Feature categories remain untouched and attribute data is
       copied from input vector map to the output.

       By default, all features (including features without  category)  from  input  vector  map  are  processed
       (layer=-1). Feature selection can be applied by layer, cats or where parameter.

EXAMPLES

   3D houses with fixed height
       v.extrude input=houses output=houses3D height=5 type=area

   3D houses with individual height
       v.extrude input=houses output=houses3D elevation=dem height_column=height type=area

   Convert 2D points to 3D vertical lines with fixed height
       v.extrude input=geodetic_pts output=points3D height=200 type=point

SEE ALSO

        v.transform, v.drape, v.to.3d

        wxGUI 3D viewer

AUTHORS

       Jachym Cepicky,
       Updated  for  GRASS  7  by  Martin Landa, FBK-irst, Italy and Czech Technical University in Prague, Czech
       Republic

SOURCE CODE

       Available at: v.extrude source code (history)

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       © 2003-2019 GRASS Development Team, GRASS GIS 7.8.2 Reference Manual