NAME
v.lrs.where - Finds line id and real km+offset for given points in vector map using linear reference system.
KEYWORDS
vector,
linear reference system,
network
SYNOPSIS
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]
Flags:
- --help
- Print usage summary
- --verbose
- Verbose module output
- --quiet
- Quiet module output
- --ui
- Force launching GUI dialog
Parameters:
- lines=name [required]
- Name of input vector map
- Input vector map containing lines
- points=name [required]
- Name of input vector map
- Input vector map containing points
- llayer=string
- Layer number or name
- Line layer
- Default: 1
- player=string
- Layer number or name
- Point layer
- Default: 1
- rsdriver=string
- Driver name for reference system table
- Options: dbf, odbc, ogr, pg, sqlite
- Default: sqlite
- rsdatabase=string
- Database name for reference system table
- Default: $GISDBASE/$LOCATION_NAME/$MAPSET/sqlite/sqlite.db
- rstable=string [required]
- Name of the reference system table
- threshold=float
- 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
v.lrs.where,
v.lrs.segment,
v.lrs.label
LRS tutorial,
Introducing the Linear Reference System in GRASS
Radim Blazek, ITC-irst/MPA Solutions
Documentation update (based on above journal article and available fragments): Markus Neteler
SOURCE CODE
Available at:
v.lrs.where source code
(history)
Latest change: Thursday Jan 26 14:10:26 2023 in commit: cdd84c130cea04b204479e2efdc75c742efc4843
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© 2003-2024
GRASS Development Team,
GRASS GIS 8.5.0dev Reference Manual