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 = 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) $

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       © 2003-2013 GRASS Development Team