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NAME

       t.rast.accdetect   -  Detects  accumulation  patterns in temporally accumulated space time
       raster datasets created by t.rast.accumulate.

KEYWORDS

       temporal, accumulation, raster, time

SYNOPSIS

       t.rast.accdetect
       t.rast.accdetect --help
       t.rast.accdetect  [-nr]  input=name   [minimum=name]     [maximum=name]    occurrence=name
       [indicator=name]      start=string      [stop=string]     cycle=string     [offset=string]
       basename=string    [suffix=string]     [range=min,max]     [staend=start,intermediate,end]
       [--overwrite]  [--help]  [--verbose]  [--quiet]  [--ui]

   Flags:
       -n
           Register  empty  maps  in the output space time raster dataset, otherwise they will be
           deleted

       -r
           Reverse time direction in cyclic accumulation

       --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

       minimum=name
           Input space time raster dataset that  specifies  the  minimum  values  to  detect  the
           accumulation pattern

       maximum=name
           Input  space  time  raster  dataset  that  specifies  the maximum values to detect the
           accumulation pattern

       occurrence=name [required]
           The  output  space  time  raster  dataset  that  stores  the  occurrence  of  the  the
           accumulation pattern using the provided data range

       indicator=name
           The  output  space  time  raster  dataset  that  stores  the  indication of the start,
           intermediate and end of the specified data range

       start=string [required]
           The temporal starting point to begin the accumulation, eg ’2001-01-01’

       stop=string
           The temporal date to stop the accumulation, eg ’2009-01-01’

       cycle=string [required]
           The temporal cycle to restart the accumulation, eg ’12 months’

       offset=string
           The temporal offset to the begin of the next cycle, eg ’6 months’

       basename=string [required]
           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, ’count’ for numerical suffix with a specific number of digits (default %05)
           Default: gran

       range=min,max
           The minimum and maximum value of the occurrence of accumulated  values,  these  values
           will be used if the min/max space time raster datasets are not specified

       staend=start,intermediate,end
           The  user  defined  values  that  indicate  start,  intermediate and end status in the
           indicator output space time raster dataset
           Default: 1,2,3

DESCRIPTION

       t.rast.accdetect is designed to detect  accumulation  pattern  in  temporally  accumulated
       space  time  raster datasets created by t.rast.accumulate.  This module’s input is a space
       time raster dataset resulting from a t.rast.accumulate run.

       The start time and the end time  of  the  pattern  detection  process  must  be  set,  eg.
       start="2000-03-01" end="2011-01-01".  The start and end time do not need to be the same as
       for the accumulation run that produced the input space time raster dataset.  In addition a
       cycle,  eg.  "8  months",  can  be  specified,  that defines after which time interval the
       accumulation pattern detection process restarts. The offset option specifies the time that
       should be skipped between two cycles, eg. "4 months". The cycle and offset options must be
       exactly the same that were used in the accumulation process that generated the input space
       time  raster  dataset,  otherwise  the  accumulation  pattern detection will produce wrong
       results.

       The minimum and maximum values for the pattern detection process  can  be  set  either  by
       using  space  time  raster datasets or by using fixed values for all raster cells and time
       steps.

       Using space time raster datasets allows specifying minimum and  maximum  values  for  each
       raster  cell  and  each time step. For example, we want to detect the germination (minimum
       value) and harvesting (maximum value) dates for  different  crops  in  Germany  using  the
       growing-degree-day  (GDD)  method for several years. Different crops may grow in different
       raster cells and change with time because of crop  rotation.  Hence  we  need  to  specify
       different  GDD  germination/harvesting (minimum/maximum) values for different raster cells
       and different years.

       The raster maps that specify the minimum and maximum values of the actual granule will  be
       detected  using the following temporal relations: equals, during, overlaps, overlapped and
       contains. First, all maps with time stamps equal to the current granule of the input STRDS
       will  be  detected, the first minimum map and the first maximum map that are found will be
       used as range definitions. If no equal maps are found, then maps with  a  temporal  during
       relation  will  be  detected,  then  maps  that temporally overlap the actual granules and
       finally, maps that have a temporal contain relation will be detected. If no maps are found
       or minimum/maximum STRDS are not set, then the range option is used, eg. range=480,730.

       The base name of of the generated maps must always be set.

       This  module produces two output space time raster datasets: occurrence and indicator. The
       occurrence output STRDS stores the time in days from the beginning of a  given  cycle  for
       each raster cell and time step that has a value within the minimum and maximum definition.
       These values can be used to compute the duration of the recognized  accumulation  pattern.
       The  indicator  output  STRDS uses three integer values to mark raster cells as beginning,
       intermediate state or end of an accumulation pattern. By default, the  module  uses  1  to
       indicate the start, 2 for the intermediate state and 3 to mark the end of the accumulation
       pattern in a cycle. These default values can be changed using the staend option.

EXAMPLE

       Please have a look at the t.rast.accumulate example.

SEE ALSO

         t.rast.accumulate,  t.rast.aggregate,   t.rast.mapcalc,   t.info,   r.series.accumulate,
       g.region

AUTHOR

       Sören Gebbert, Thünen Institute of Climate-Smart Agriculture

       Last changed: $Date: 2017-11-18 09:59:58 +0100 (Sat, 18 Nov 2017) $

SOURCE CODE

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

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