---
name: "v.lrs.where"
section: "1grass"
platform: "linux"
package: "grass-doc"
version: "8.4.1-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/v.lrs.where"
---

# v.lrs.where(1grass)

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

## 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, mysql, 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*

## 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 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
```

## SEE ALSO

*v.lrs.where,* *v.lrs.segment,* *v.lrs.label*

*LRS tutorial,*\
 *Introducing the Linear Reference System in GRASS*

## AUTHORS

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)

Accessed: Monday Feb 24 17:51:19 2025

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