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v.lrs.where(1grass) Grass User's Manual v.lrs.where(1grass)

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

vector, linear reference system, network

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


Print usage summary

Verbose module output

Quiet module output

Force launching GUI dialog


Name of input vector map
Input vector map containing lines

Name of input vector map
Input vector map containing points

Layer number or name
Line layer
Default: 1

Layer number or name
Point layer
Default: 1

Driver name for reference system table
Options: dbf, mysql, odbc, ogr, pg, sqlite
Default: sqlite

Database name for reference system table
Default: $GISDBASE/$LOCATION_NAME/$MAPSET/sqlite/sqlite.db

Name of the reference system table

Maximum distance to nearest line
Default: 1000

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

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 vector=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:
# use measuring tool in graphical user interface

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

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

Last changed: $Date: 2014-12-19 22:17:36 +0100 (Fri, 19 Dec 2014) $

Available at: v.lrs.where source code (history)

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GRASS 7.6.0