t.vect.extract
Extracts a subset of a space time vector dataset.
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] [--verbose] [--quiet] [--qq] [--ui]
Example:
t.vect.extract input=name output=name
grass.script.run_command("t.vect.extract", input, where=None, expression=None, output, layer="1", type="point,line,boundary,centroid,area", basename=None, suffix="gran", nprocs=1, flags=None, overwrite=False, verbose=False, quiet=False, superquiet=False)
Example:
gs.run_command("t.vect.extract", input="name", output="name")
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
Allowed values: 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
-n
Register empty maps
--overwrite
Allow output files to overwrite existing files
--help
Print usage summary
--verbose
Verbose module output
--quiet
Quiet module output
--qq
Very quiet module output
--ui
Force launching GUI dialog
input : str, required
Name of the input space time vector dataset
Used as: input, stvds, name
where : str, optional
WHERE conditions of SQL statement without 'where' keyword used in the temporal GIS framework
Example: start_time > '2001-01-01 12:30:00'
Used as: sql_query
expression : str, optional
WHERE conditions of SQL statement without 'where' keyword
Example: income < 1000 and population >= 10000
Used as: input, sql_query, sql_query
output : str, required
Name of the output space time vector dataset
Used as: output, stvds, name
layer : str, optional
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.
Used as: input, layer
Default: 1
type : str | list[str], optional
Input feature type
Allowed values: point, line, boundary, centroid, area
Default: point,line,boundary,centroid,area
basename : str, optional
Basename of the new generated output maps
A numerical suffix separated by an underscore will be attached to create a unique identifier
suffix : str, optional
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 : int, optional
The number of v.extract processes to run in parallel. Use only if database backend is used which supports concurrent writing
Default: 1
flags : str, optional
Allowed values: n
n
Register empty maps
overwrite: bool, optional
Allow output files to overwrite existing files
Default: False
verbose: bool, optional
Verbose module output
Default: False
quiet: bool, optional
Quiet module output
Default: False
superquiet: bool, optional
Very quiet module output
Default: False
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
AUTHOR
Sören Gebbert, Thünen Institute of Climate-Smart Agriculture
SOURCE CODE
Available at: t.vect.extract source code
(history)
Latest change: Wednesday Apr 02 17:48:37 2025 in commit 571253a