<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <title>GRASS GIS: v.lrs.where</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.lrs.where</b></em> - Finds line id and real km+offset for given points in vector map using linear reference system. <h2>KEYWORDS</h2> vector, LRS, networking <h2>SYNOPSIS</h2> <b>v.lrs.where</b><br> <b>v.lrs.where help</b><br> <b>v.lrs.where</b> <b>lines</b>=<em>name</em> <b>points</b>=<em>name</em> [<b>llayer</b>=<em>integer</em>] [<b>player</b>=<em>integer</em>] <b>rstable</b>=<em>string</em> [<b>thresh</b>=<em>float</em>] [--<b>verbose</b>] [--<b>quiet</b>] <h3>Parameters:</h3> <DL> <DT><b>lines</b>=<em>name</em></DT> <DD>Input vector map containing lines</DD> <DT><b>points</b>=<em>name</em></DT> <DD>Input vector map containing points</DD> <DT><b>llayer</b>=<em>integer</em></DT> <DD>Layer number</DD> <DD>Line layer</DD> <DD>Default: <em>1</em></DD> <DT><b>player</b>=<em>integer</em></DT> <DD>Layer number</DD> <DD>Point layer</DD> <DD>Default: <em>1</em></DD> <DT><b>rstable</b>=<em>string</em></DT> <DD>Name of the reference system table</DD> <DT><b>thresh</b>=<em>float</em></DT> <DD>Maximum distance to nearest line</DD> <DD>Default: <em>1000</em></DD> </DL> <h2>DESCRIPTION</h2> <em>v.lrs.where</em> identifies line id and real milepost+offset for points in vector map using linear reference system. <h2>EXAMPLE</h2> This example is written for the Spearfish dataset (it continues the example from <em>v.lrs.create</em>). <p> In this example, the 'route_lrs' shall be queried for unknown positions (points, stored in the map <em>newpoints</em>) along the LRS: <div class="code"><pre> # generate query points echo "590866.15|4926737.0 590933|4927133" | v.in.ascii out=newpoints v.lrs.where lines=route_lrs points=newpoints rstable=route_lrs pcat|lid|mpost|offset pcat|lid|mpost|offset 1|22|4.000000+212.091461 2|22|6.000000+188.112093 # verification g.region vect=route_lrs n=n+100 s=s-100 -p d.erase d.vect route_lrs d.vect busstops disp=attr attr=cat size=10 bg=white lcol=blue yref=bottom d.vect busstops icon=basic/circle fcol=blue d.vect newpoints col=red # measure distance to previous bus stop d.measure </pre></div> <h2>SEE ALSO</h2> <em><a HREF="lrs.html">LRS tutorial</a></em>,<br> <em><a HREF="http://gisws.media.osaka-cu.ac.jp/grass04/viewpaper.php?id=50">Introducing the Linear Reference System in GRASS</a></em>,<br> <em><a HREF="v.lrs.create.html">v.lrs.where</a></em>, <em><a HREF="v.lrs.segment.html">v.lrs.segment</a></em>, <em><a HREF="v.lrs.label.html">v.lrs.label</a></em> <h2>AUTHOR</h2> Radim Blazek, ITC-irst/MPA Solutions<br> Documentation update (based on above journal article and available fragments): Markus Neteler <p><i>Last changed: $Date: 2007-06-28 17:28:50 +0200 (Thu, 28 Jun 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>
