t.rast.contour(1grass)

NAME
t.rast.contour - Produces a space time vector dataset of specified contours from a space time raster dataset.

KEYWORDS
temporal, contour, raster, vector, time

SYNOPSIS
t.rast.contour
t.rast.contour --help
t.rast.contour [-nt] input=name output=name [where=sql_query] basename=string [suffix=string] [step=float] [levels=float[,float,...]] [minlevel=float] [maxlevel=float] [cut=integer] [nprocs=integer] [--overwrite] [--help] [--verbose] [--quiet] [--ui]

  Flags:

-n
    Register empty vector maps

-t
    Do not create attribute tables

--overwrite
    Allow output files to overwrite existing files

--help
    Print usage summary

--verbose
    Verbose module output

--quiet
    Quiet module output

--ui
    Force launching GUI dialog

  Parameters:

input=name [required]
    Name of the input space time raster dataset

output=name [required]
    Name of the output space time vector dataset

where=sql_query
    WHERE conditions of SQL statement without ’where’ keyword used in the temporal GIS framework
    Example: start_time > ’2001-01-01 12:30:00’

basename=string [required]
    Basename of the new generated output maps
    A numerical suffix separated by an underscore will be attached to create a unique identifier

suffix=string
    Suffix to add at basename: set ’gran’ for granularity, ’time’ for the full time format, ’num’ for numerical suffix with a specific number of digits (default %05)
    Default: gran

step=float
    Increment between contour levels

levels=float[,float,...]
    List of contour levels

minlevel=float
    Minimum contour level

maxlevel=float
    Maximum contour level

cut=integer
    Minimum number of points for a contour line (0 -> no limit)
    Default: 0

nprocs=integer
    Number of r.contour processes to run in parallel, more than 1 process works only in conjunction with flag -t
    Default: 1

DESCRIPTION
t.rast.contour is designed to produce a space time vector dataset of specified contours from a space time raster dataset. This module works as a front-end to r.contour and therefore supports all parameter of this module. Hence, all raster map layers in a space time raster dataset are successively passed to r.contour that computes the contour lines. Please refer to the r.contour documentation for a detailed description. The new generated vector contour map layers will be registered in the output space time vector dataset, using the same time stamps as their raster map layer origins.

This module supports the parallel processing of r.contour module instances. The number of parallel processes can be set with the nprocs option. However, this will only work in conjunction with the -t flag, that avoids the creation of attribute tables. The parallel creation of attribute tables is not supported.

The where option allows selecting subsets of the input space time raster dataset.

The flag -n can be used to force the registration of empty vector map layers. Empty vector maps may occur in case that empty raster map layers should be converted into vector map layers, or in case the chosen steps or contour levels are not present in the raster map layers.

SEE ALSO
r.contour, t.rast.db.select, t.info

AUTHOR
Sören Gebbert, Geoinformatikbüro Dassau

SOURCE CODE

Available at: t.rast.contour source code (history)

Accessed: Thursday Oct 30 22:18:59 2025

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