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) $

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       © 2003-2013 GRASS Development Team