t.vect.extract(1)

NAME
t.vect.extract - Extracts a subset of a space time vector dataset.

KEYWORDS
temporal, extract, vector, time

SYNOPSIS
t.vect.extract
t.vect.extract --help
t.vect.extract [-n] input=name [where=sql_query] [expression=sql_query] output=name [layer=string] [type=string[,string,...]] [basename=string] [suffix=string] [nprocs=integer] [--overwrite] [--help] [--verbose] [--quiet] [--ui]

  Flags:

-n
    Register empty maps

--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 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’

expression=sql_query
    WHERE conditions of SQL statement without ’where’ keyword
    Example: income < 1000 and population >= 10000

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

layer=string
    Layer number or name
    Vector features can have category values in different layers. This number determines which layer to use. When used with direct OGR access this is the layer name.
    Default: 1

type=string[,string,...]
    Input feature type
    Options: point, line, boundary, centroid, area
    Default: point,line,boundary,centroid,area

basename=string
    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

nprocs=integer
    The number of v.extract processes to run in parallel. Use only if database backend is used which supports concurrent writing
    Default: 1

DESCRIPTION
The purpose of t.vect.extract is to extract a subset of a space time vector dataset and to store that subset in a different space time vector dataset.

EXAMPLE
In the following example a new space time vector dataset will be create with all the data later than the year 2000:

t.vect.extract input=shoreline where="start_time > 2000" \
               output=shoreline_later_2000 basename=new_shoreline
t.info shoreline_later_2000@shoreline type=stvds
 +-------------------- Space Time Vector Dataset -----------------------------+
 |                                                                            |
 +-------------------- Basic information -------------------------------------+
 | Id: ........................ shoreline_later_2000@shoreline
 | Name: ...................... shoreline_later_2000
 | Mapset: .................... shoreline
 | Creator: ................... lucadelu
 | Temporal type: ............. relative
 | Creation time: ............. 2014-11-29 08:43:50.043219
 | Modification time:.......... 2014-11-29 08:43:50.085407
 | Semantic type:.............. mean
 +-------------------- Relative time -----------------------------------------+
 | Start time:................. 2003
 | End time:................... 2009
 | Relative time unit:......... years
 | Granularity:................ 1
 | Temporal type of maps:...... point
 +-------------------- Spatial extent ----------------------------------------+
 | North:...................... 1039175.31479
 | South:...................... 34705.216018
 | East:.. .................... 3052322.44671
 | West:....................... 2130004.16779
 | Top:........................ 0.0
 | Bottom:..................... 0.0
 +-------------------- Metadata information ----------------------------------+
 | Vector register table:...... vector_map_register_8395740fc8de42149fef74a3d25bbb05
 | Number of points ........... 0
 | Number of lines ............ 407
 | Number of boundaries ....... 0
 | Number of centroids ........ 0
 | Number of faces ............ 0
 | Number of kernels .......... 0
 | Number of primitives ....... 407
 | Number of nodes ............ 767
 | Number of areas ............ 0
 | Number of islands .......... 0
 | Number of holes ............ 0
 | Number of volumes .......... 0
 | Number of registered maps:.. 3
 |
 | Title:
 | North Carolina shoreline
 | Description:
 | North Caroline shoreline from 2000 to 2009
 | Command history:
 | # 2014-11-29 08:43:50
 | t.vect.extract input="shoreline"
 |     where="start_time > 2000" output="shoreline_later_2000"
 |     basename="new_shoreline"
 | # 2014-11-29 08:44:14
 | t.support type="stvds"
 |     input="shoreline_later_2000@shoreline"
 |     descr="North Caroline shoreline from 2000 to 2009"
 +----------------------------------------------------------------------------+
t.vect.list shoreline_later_2000
name|layer|mapset|start_time|end_time
shoreline_2003|None|shoreline|2003|None
shoreline_2004|None|shoreline|2004|None
shoreline_2009|None|shoreline|2009|None

SEE ALSO
t.create, t.info

AUTHOR
Sören Gebbert, Thünen Institute of Climate-Smart Agriculture

SOURCE CODE

Available at: t.vect.extract source code (history)

Accessed: Wednesday Feb 04 01:06:58 2026

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