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v.drape.1grass - Man Page

Converts 2D vector features to 3D by sampling of elevation raster map.


vector, geometry, sampling, 3D, surface information


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



Allow output files to overwrite existing files


Print usage summary


Verbose module output


Quiet module output


Force launching GUI dialog


input=name [required]

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


Category values
Example: 1,3,7-9,13


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


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

output=name [required]

Name for output vector map

elevation=name [required]

Elevation raster map for height extraction


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


Scale factor sampled raster values
Default: 1.0


Height for sampled raster NULL values


v.drape converts 2D/3D vector data into 3D vector format via sampling of an elevation surface. Three sampling algorithms adapted from v.sample were incorporated into this module: nearest neighbor, bilinear, and cubic convultion.

v.drape will skip vector features outside of current computational region or where raster map has NULL value. It’s possible to include all vector features by specifying height value that will be assigned to verticles whose values can not be determined from raster map.


Additional vertices can be added to the input 2D vector map with v.split.

The module can be used in conjunction with v.out.pov and r.out.pov to export a complete set of vector and raster data for display in POVRAY.


Spearfish example:

v.drape in=roads elevation=elevation.10m method=bilinear out=roads3d
v.info roads3d

Create 3D vector roads map containing only "unimproved" roads. Set road height to 1000 m for all parts without height information.

v.drape input=roads type=line elevation=elevation.dem output=roads_3d \
        method=nearest scale=1.0 where=’cat=5’ layer=1 null_value=1000

POVRAY example

#export the vector data
v.drape in=roads out=roads3d elevation=elevation.10m
v.out.pov roads3d out=roads3d.pov
#export the raster data
r.out.pov elevation.10m tga=elevation.tga
r.out.png landcover.30m out=landcover30m.png
# now write a complete povray-script and launch povray

See Also

v.extrude, v.to.3d, r.out.pov, v.in.region, v.out.pov, v.overlay, v.split, v.what.rast


Dylan Beaudette, University of California at Davis.
Updated for GRASS 7 by Martin Landa, Czech Technical University in Prague, Czech Republic

Source Code

Available at: v.drape source code (history)

Accessed: Tuesday May 14 13:41:09 2024

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