## NAME

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

## KEYWORDS

vector, geometry, sampling, 3D, surface information

## SYNOPSIS

v.drape
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]

### Flags:

--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, boundary, centroid
  Default: point,line,boundary,centroid
output=name [required]
  Name for output vector map
elevation=name [required]
  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.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.

## NOTES

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.

## EXAMPLES

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

## AUTHORS

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: Sunday Sep 03 20:21:05 2023

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