
NAME
v.drape - Convert 2D vector to 3D vector by sampling of elevation raster. Default sampling by nearest neighbor
KEYWORDS
vector
SYNOPSIS
v.drape
v.drape help
v.drape input=name [type=string[,string,...]] [rast=string] [method=string] output=name [--overwrite]
Flags:
- --overwrite
- Force overwrite of output files
Parameters:
- input=name
- Name of input vector map
- type=string[,string,...]
- Type
- Options: point,centroid,line,boundary,face,kernel
- Default: point,centroid,line,boundary,face,kernel
- rast=string
- Elevation raster for height extraction
- method=string
- Sampling method
- Options: nearest,bilinear,cubic
- Default: nearest
- nearest: nearest neighbor
- bilinear: bilinear interpolation
- cubic: cubic convolution interpolation
- output=name
- Name for output vector map
DESCRIPTION
v.drape converts 2D vector point or line data into 3D vector
format via sampling of an elevation surface. Three sampling algorithms
adapted fromv v.sample were incorporated into this module:
nearest neighbor, bilinear, and cubic convultion.
NOTES
Please run beforehand
and make sure that the extent of the elevation raster is at least as
big as the vector to convert.
Additional vertices can be added to the input 2D vector 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.
EXAMPLE
Spearfish example:
g.region -p vect=roads align=elevation.10m
v.drape in=roads rast=elevation.10m method=bilinear out=roads3d
v.info roads3d
POVRAY EXAMPLE
#setup the region
g.region vect=roads align=elevation.10m -p
#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
ERROR MESSAGES
If the following error message appears
WARNING: [demname in mapset] - read request for row -1 is outside region
ERROR: problem reading raster cell file
it indicates that the vector map is spatially larger than the raster map.
To avoid this problem, the vector map needs to be clipped to the raster
map extent, for example:
g.region rast=demname
v.in.region clipbox
v.overlay ain=clipbox bin=vectmap out=vectmap_clipped op=and
v.drape vectmap_clipped out=vectdrape rast=demname
Then v.drape should perform the draping.
SEE ALSO
r.out.pov,
v.in.region,
v.out.pov,
v.overlay,
v.split,
v.what.rast
AUTHOR
Dylan Beaudette, University of California at Davis.
Raster sampling routines borrowed from v.sample.
Last changed: $Date: 2007/07/09 15:15:57 $
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