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]
       [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

       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

       Last changed: $Date: 2015-09-22 10:12:20 +0200 (Tue, 22 Sep 2015) $

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       © 2003-2016 GRASS Development Team, GRASS GIS 7.0.3 Reference Manual

GRASS 7.0.3                                                                               t.rast.extract(1grass)