GRASS logo

Note: A new GRASS GIS stable version has been released: GRASS GIS 7, available here. And see the new manual page here

NAME

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

KEYWORDS

vector, geometry, sampling

SYNOPSIS

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

Flags:

--overwrite
Allow output files to overwrite existing files
--verbose
Verbose module output
--quiet
Quiet module output

Parameters:

input=name
Name of input vector map
type=string[,string,...]
Feature type
Options: point,centroid,line,boundary,face,kernel
Default: point,centroid,line,boundary,face,kernel
rast=name
Elevation raster map for height extraction
output=name
Name for output vector map
method=string
Sampling method
Options: nearest,bilinear,cubic
Default: nearest
nearest: nearest neighbor
bilinear: bilinear interpolation
cubic: cubic convolution interpolation
scale=float
Scale sampled raster values
Default: 1.0
where=sql_query
WHERE conditions of SQL statement without 'where' keyword
Example: income < 1000 and inhab >= 10000
layer=integer
Layer number
Layer is only used for WHERE SQL statement
Default: 1
null_value=float
Vector Z value for unknown height
Will set Z to this value, if value from raster map can not be read

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 rast=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 rast=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 rast=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

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

AUTHOR

Dylan Beaudette, University of California at Davis.

Last changed: $Date: 2011-11-08 03:29:50 -0800 (Tue, 08 Nov 2011) $


Main index - vector index - Full index

© 2003-2016 GRASS Development Team