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v.lrs.where.1grass

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 17:28:50 +0200 (gio, 28 giu 2007) $

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