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t.rast.extract - Extracts a subset of a space time raster datasets.


temporal, extract, raster, time


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


Register Null maps
Allow output files to overwrite existing files
Print usage summary
Verbose module output
Quiet module output
Force launching GUI dialog


input=name [required]
Name of the input space time raster dataset
WHERE conditions of SQL statement without 'where' keyword used in the temporal GIS framework
Example: start_time > '2001-01-01 12:30:00'
r.mapcalc expression assigned to all extracted raster maps
output=name [required]
Name of the output space time raster dataset
Basename of the new generated output maps
A numerical suffix separated by an underscore will be attached to create a unique identifier
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
Number of r.mapcalc processes to run in parallel
Default: 1

Table of contents


The purpose of t.rast.extract is to extract a subset of a space time raster dataset and to store that subset in a different space time raster dataset. The where condition is used to select the subset. In addition a r.mapcalc sub-expression can be specified that performs operations on all maps of the selected subset. In this expression the name of the input space time raster dataset can be used as simple map name. Other STRDS than the input STRDS can not be specified, but any raster map. In case a r.mapcalc sub-expression is defined, the base name of the resulting raster maps must be specified. The r.mapcalc expression can be used to select maps as well, since by default resulting empty maps are not registered in the output space time raster dataset and removed after processing. The number of parallel GRASS GIS processes can be specified to speed up the processing.

If no r.mapcalc expression is defined, the selected maps are simply registered in the new created output space time raster dataset to avoid data duplication.


The r.mapcalc sub-expression should not contain the left side "map =" of a full r.mapcalc expression, only the right side, eg.:
t.rast.extract input=tempmean_monthly where="start_time > '2010-01-05'" \
               output=selected_tempmean_monthly basename=new_tmean_month \
               expression="if(tempmean_monthly < 0, null(), tempmean_monthly)"


t.rast.extract input=tempmean_monthly output=tempmean_monthly_later_2012 \
               where="start_time >= '2012-01-01'"

t.rast.list tempmean_monthly_later_2012
2012_01_tempmean|climate_2000_2012|2012-01-01 00:00:00|2012-02-01 00:00:00
2012_02_tempmean|climate_2000_2012|2012-02-01 00:00:00|2012-03-01 00:00:00
2012_03_tempmean|climate_2000_2012|2012-03-01 00:00:00|2012-04-01 00:00:00
2012_04_tempmean|climate_2000_2012|2012-04-01 00:00:00|2012-05-01 00:00:00
2012_05_tempmean|climate_2000_2012|2012-05-01 00:00:00|2012-06-01 00:00:00
2012_06_tempmean|climate_2000_2012|2012-06-01 00:00:00|2012-07-01 00:00:00
2012_07_tempmean|climate_2000_2012|2012-07-01 00:00:00|2012-08-01 00:00:00
2012_08_tempmean|climate_2000_2012|2012-08-01 00:00:00|2012-09-01 00:00:00
2012_09_tempmean|climate_2000_2012|2012-09-01 00:00:00|2012-10-01 00:00:00
2012_10_tempmean|climate_2000_2012|2012-10-01 00:00:00|2012-11-01 00:00:00
2012_11_tempmean|climate_2000_2012|2012-11-01 00:00:00|2012-12-01 00:00:00
2012_12_tempmean|climate_2000_2012|2012-12-01 00:00:00|2013-01-01 00:00:00




Sören Gebbert, Thünen Institute of Climate-Smart Agriculture


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

Latest change: Thursday Feb 03 11:10:06 2022 in commit: 547ff44e6aecfb4c9cbf6a4717fc14e521bec0be

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