v.drapegrass - Online in the Cloud

PROGRAM:

NAME

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

KEYWORDS

vector, geometry, sampling, 3D

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 inhab >= 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

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