## NAME

t.rast.to.vect - Converts a space time raster dataset into a space time vector dataset

## KEYWORDS

temporal, conversion, raster, vector, time

## SYNOPSIS

t.rast.to.vect
t.rast.to.vect --help
t.rast.to.vect [-ntszbv] input=name output=name [where=sql_query] type=string basename=string [suffix=string] [column=string] [nprocs=integer] [--overwrite] [--help] [--verbose] [--quiet] [--ui]

### Flags:

-n
  Register empty vector maps
-t
  Do not create attribute tables
-s
  Smooth corners of area features
-z
  Write raster values as z coordinate
  Table is not created. Currently supported only for points.
-b
  Do not build vector topology
  Name must be SQL compliant
-v
  Use raster values as categories instead of unique sequence (CELL only)
--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'
type=string [required]
  Output feature type
  Options: point, line, area
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
column=string
  Name of attribute column to store value
  Default: value
nprocs=integer
  Number of r.to.vect processes to run in parallel, more than 1 process works only in conjunction with flag -t
  Default: 1

## DESCRIPTION

t.rast.to.vect is designed to convert a space time raster dataset into a space time vector dataset. This module works as a front-end to r.to.vect and therefore supports all parameter of this module. Hence, all raster map layers in a space time raster dataset are passed to r.to.vect that converts them into vector map layers (using point,line or area as conversion criteria). Please refer to the r.to.vect documentation for a detailed description of the raster to vector conversion options. The new generated vector 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.to.vect 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.

## SEE ALSO

r.to.vect, t.rast.db.select, t.info

## AUTHOR

Sören Gebbert, Geoinformatikbüro Dassau

Last changed: $Date$

## SOURCE CODE

Available at: t.rast.to.vect source code (history)

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© 2003-2019 GRASS Development Team, GRASS GIS 7.8.0 Reference Manual