NAME

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

KEYWORDS

       temporal, extract, raster, time

SYNOPSIS

       t.rast.extract
       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]

   Flags:
       -n
           Register Null 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 raster 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=string
           r.mapcalc expression assigned to all extracted raster maps

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

       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
           Number of r.mapcalc processes to run in parallel
           Default: 1

DESCRIPTION

       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.

NOTES

       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)"

EXAMPLE

       t.rast.extract input=tempmean_monthly output=tempmean_monthly_later_2012 \
                      where="start_time >= ’2012-01-01’"
       t.rast.list tempmean_monthly_later_2012
       name|mapset|start_time|end_time
       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

SEE ALSO

        t.create, t.info

AUTHOR

       Sören Gebbert, Thünen Institute of Climate-Smart Agriculture

SOURCE CODE

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

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