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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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