NAME

       v.lrs.where   -  Finds  line  id and real km+offset for given points in vector map using linear reference
       system.

KEYWORDS

       vector, LRS, networking

SYNOPSIS

       v.lrs.where
       v.lrs.where help
       v.lrs.where   lines=name    points=name     [llayer=integer]      [player=integer]      [rsdriver=string]
       [rsdatabase=string]  rstable=string  [thresh=float]   [--verbose]  [--quiet]

   Parameters:
       lines=name
           Input vector map containing lines

       points=name
           Input vector map containing points

       llayer=integer
           Layer number
           Line layer
           Default: 1

       player=integer
           Layer number
           Point layer
           Default: 1

       rsdriver=string
           Driver name for reference system table
           Default: dbf

       rsdatabase=string
           Database name for reference system table
           Default: $GISDBASE/$LOCATION_NAME/$MAPSET/dbf/

       rstable=string
           Name of the reference system table

       thresh=float
           Maximum distance to nearest line
           Default: 1000

DESCRIPTION

       v.lrs.where  identifies  line id and real milepost+offset for points in vector map using linear reference
       system.

EXAMPLE

       This example is written for the Spearfish dataset (it continues the example from v.lrs.create).

       In this example, the 'route_lrs' shall be queried for  unknown  positions  (points,  stored  in  the  map
       newpoints) along the LRS:
       # 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

SEE ALSO

       LRS tutorial,
       Introducing the Linear Reference System in GRASS,
       v.lrs.where, v.lrs.segment, v.lrs.label

AUTHOR

       Radim Blazek, ITC-irst/MPA Solutions
       Documentation update (based on above journal article and available fragments): Markus Neteler

       Last changed: $Date: 2007-06-28 08:28:50 -0700 (Thu, 28 Jun 2007) $

       Full index

       © 2003-2013 GRASS Development Team

GRASS 6.4.3                                                                                  v.lrs.where(1grass)