<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <title>GRASS GIS: v.drape</title> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> <link rel="stylesheet" href="grassdocs.css" type="text/css"> </head> <body bgcolor="white"> <img src="grass_logo.png" alt="GRASS logo"><hr align=center size=6 noshade> <h2>NAME</h2> <em><b>v.drape</b></em> - Converts 2D vector to 3D vector by sampling of elevation raster. Default sampling by nearest neighbor. <h2>KEYWORDS</h2> vector <h2>SYNOPSIS</h2> <b>v.drape</b><br> <b>v.drape help</b><br> <b>v.drape</b> <b>input</b>=<em>name</em> [<b>type</b>=<em>string</em>[,<i>string</i>,...]] [<b>rast</b>=<em>string</em>] [<b>method</b>=<em>string</em>] <b>output</b>=<em>name</em> [--<b>overwrite</b>] [--<b>verbose</b>] [--<b>quiet</b>] <h3>Flags:</h3> <DL> <DT><b>--overwrite</b></DT> <DD>Allow output files to overwrite existing files</DD> <DT><b>--verbose</b></DT> <DD>Verbose module output</DD> <DT><b>--quiet</b></DT> <DD>Quiet module output</DD> </DL> <h3>Parameters:</h3> <DL> <DT><b>input</b>=<em>name</em></DT> <DD>Name of input vector map</DD> <DT><b>type</b>=<em>string[,<i>string</i>,...]</em></DT> <DD>Type</DD> <DD>Feature type(s)</DD> <DD>Options: <em>point,centroid,line,boundary,face,kernel</em></DD> <DD>Default: <em>point,centroid,line,boundary,face,kernel</em></DD> <DT><b>rast</b>=<em>string</em></DT> <DD>Elevation raster for height extraction</DD> <DT><b>method</b>=<em>string</em></DT> <DD>Sampling method</DD> <DD>Options: <em>nearest,bilinear,cubic</em></DD> <DD>Default: <em>nearest</em></DD> <DD><b>nearest</b>: nearest neighbor</DD> <DD><b>bilinear</b>: bilinear interpolation</DD> <DD><b>cubic</b>: cubic convolution interpolation</DD> <DT><b>output</b>=<em>name</em></DT> <DD>Name for output vector map</DD> </DL> <h2>DESCRIPTION</h2> <em>v.drape</em> converts 2D vector point or line data into 3D vector format via sampling of an elevation surface. Three sampling algorithms adapted from<em>v v.sample</em> were incorporated into this module: nearest neighbor, bilinear, and cubic convultion. <h2>NOTES</h2> Please run beforehand <div class="code"><pre> g.region vect=2D_vector </pre></div> and make sure that the extent of the elevation raster is at least as big as the vector to convert. <P> Additional vertices can be added to the input 2D vector with <em>v.split</em>. <P> The module can be used in conjunction with <em>v.out.pov</em> and <em>r.out.pov</em> to export a complete set of vector and raster data for display in POVRAY. <h2>EXAMPLE</h2> Spearfish example: <P> <div class="code"><pre> g.region -p vect=roads align=elevation.10m v.drape in=roads rast=elevation.10m method=bilinear out=roads3d v.info roads3d </pre></div> <h2>POVRAY EXAMPLE</h2> <div class="code"><pre> #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 </pre></div> <h2>ERROR MESSAGES</h2> If the following error message appears <div class="code"><pre> WARNING: [demname in mapset] - read request for row -1 is outside region ERROR: problem reading raster cell file </pre></div> 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: <div class="code"><pre> 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 </pre></div> Then <em>v.drape</em> should perform the draping. <h2>SEE ALSO</h2> <EM> <A HREF="r.out.pov.html">r.out.pov</A>, <A HREF="v.in.region.html">v.in.region</A>, <A HREF="v.out.pov.html">v.out.pov</A>, <A HREF="v.overlay.html">v.overlay</A>, <A HREF="v.split.html">v.split</A>, <A HREF="v.what.rast.html">v.what.rast</A> </EM> <h2>AUTHOR</h2> Dylan Beaudette, University of California at Davis. <br> Raster sampling routines borrowed from v.sample. <p><i>Last changed: $Date: 2007-07-09 17:15:36 +0200 (Mon, 09 Jul 2007) $</i> <HR> <P><a href="index.html">Main index</a> - <a href="vector.html">vector index</a> - <a href="full_index.html">Full index</a></P> <P>© 2003-2008 <a href="http://grass.osgeo.org">GRASS Development Team</a></p> </body> </html>
