r.transect - GRASS manual
Author: GRASS Development Team
Description: r.transect: Outputs raster map layer values lying along user defined transect line(s).
Keywords: raster, profile, transect

## NAME

r.transect - Outputs raster map layer values lying along user defined transect line(s).

## KEYWORDS

raster, profile, transect

## SYNOPSIS

r.transect
r.transect --help
r.transect [-g] map=name line=east,north,azimuth,distance[,east,north,azimuth,distance,...] [null_value=string] [--help] [--verbose] [--quiet] [--ui]

### Flags:

-g
  Output easting and northing in first two columns of four column output
--help
  Print usage summary
--verbose
  Verbose module output
--quiet
  Quiet module output
--ui
  Force launching GUI dialog

### Parameters:

map=name [required]
  Raster map to be queried
line=east,north,azimuth,distance[,east,north,azimuth,distance,...] [required]
  Transect definition
null_value=string
  String representing NULL value
  Default: *

## DESCRIPTION

r.transect outputs, in ASCII, the values in a raster map which lie along one or more user-defined transect lines. The transects are described by their starting coordinates, azimuth, and distance.

The line parameter is a definition of (each) transect line, specified by the geographic coordinates of its starting point (easting, northing), the angle and direction of its travel (azimuth), and its distance (distance).

The azimuth is an angle, in degrees, measured to the east of north. The distance is in map units (meters for a metered database, like UTM).

The null parameter can optionally be set to change the character string representing null values.

## NOTES

This program is a front-end to the r.profile program. It simply converts the azimuth and distance to an ending coordinate and then runs r.profile. There once were width= and result=raw|median|average options which are not currently implemented.

## SEE ALSO

r.profile, wxGUI profile tool

## AUTHOR

Michael Shapiro, U.S. Army Construction Engineering Research Laboratory

## SOURCE CODE

Available at: r.transect source code (history)

Accessed: Saturday May 09 13:00:18 2026

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