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NAME

       r.series.accumulate   - Makes each output cell value a accumulationfunction of the values assigned to the
       corresponding cells in the input raster map layers.

KEYWORDS

       raster, series, accumulation

SYNOPSIS

       r.series.accumulate
       r.series.accumulate --help
       r.series.accumulate   [-nzf]    [basemap=name]     [input=name[,name,...]]     [file=name]    output=name
       [scale=float]    [shift=float]    [lower=name]    [upper=name]    [range=min,max]    [limits=lower,upper]
       [method=string]   [--overwrite]  [--help]  [--verbose]  [--quiet]  [--ui]

   Flags:
       -n
           Propagate NULLs

       -z
           Do not keep files open

       -f
           Create a FCELL map (floating point single precision) as output

       --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:
       basemap=name
           Existing map to be added to output

       input=name[,name,...]
           Name of input raster map(s)

       file=name
           Input file with raster map names, one per line

       output=name [required]
           Name for output raster map

       scale=float
           Scale factor for input
           Default: 1.0

       shift=float
           Shift factor for input
           Default: 0.0

       lower=name
           The raster map specifying the lower accumulation limit, also called baseline

       upper=name
           The raster map specifying the upper accumulation limit, also called  cutoff.  Only  applied  to  BEDD
           computation.

       range=min,max
           Ignore values outside this range

       limits=lower,upper
           Use these limits in case lower and/or upper input maps are not defined
           Default: 10,30

       method=string
           This method will be applied to compute the accumulative values from the input maps
           Options: gdd, bedd, huglin, mean
           Default: gdd
           gdd: Growing Degree Days or Winkler indices
           bedd: Biologically Effective Degree Days
           huglin: Huglin Heliothermal index
           mean: Mean: sum(input maps)/(number of input maps)

DESCRIPTION

       r.series.accumulate  calculates  (accumulated)  raster  value  using  growing  degree days (GDDs)/Winkler
       indices’s, Biologically Effective Degree Days (BEDD), Huglin heliothermal indices or an average  approach
       from  several input maps for a given day. Accumulation of e.g.  degree-days to growing degree days (GDDs)
       can be done by providing a basemap with GDDs of the previous day.

       The flag -a determines the average computation of the input raster maps.  In case the flag  is  not  set,
       the average calculation is:
           average = (min + max) / 2
       In case the flag was set, the calculation changes to arithmetic mean
           average = sum(input maps) / (number of input maps)

       GDD Growing Degree Days are calculated as
           gdd = average - lower

       In  case  the  -a  is set, the Winkler indices are calculated instead of GDD, usually accumulated for the
       period April 1st to October 31st (northern hemisphere) or the period October 1st to April 30th  (southern
       hemisphere).

       BEDDs Biologically Effective Degree Days are calculated as
           bedd = average - lower
       with an optional upper cutoff applied to the average instead of the temperature values.

       The Huglin heliothermal index is calculated as
           huglin = (average + max) / 2 - lower
       usually  accumulated  for  the  period  April  1st  to September 30th (northern hemisphere) or the period
       September 1st to April 30th (southern hemisphere).

       Mean raster values are calculated as
           mean = average

       For all the formulas min is the minimum value, max the maximum value and average the average value.   The
       min, max and average values are automatically calculated from the input maps.

       The shift and scale values are applied directly to the input values. The lower and upper maps, as well as
       the range options are applied to constrain the accumulation. In case the lower and  upper  maps  are  not
       provided the limits option with default values will be applied.

       If an existing map is provided with the basemap option, the values of this map are added to the output.

NOTES

       The scale and shift parameters are used to transform input values with
           new = old * scale + shift

       With  the  -n flag, any cell for which any of the corresponding input cells are NULL is automatically set
       to NULL (NULL propagation) and the accumulated value is not calculated.

       Negative results are set to 0 (zero).

       Without the -n flag, all non-NULL cells are used for calculation.

       If the range= option is given, any values which fall outside that range will be treated as if  they  were
       NULL. Note that the range is applied to the scaled and shifted input data. The range parameter can be set
       to low,high thresholds: values outside of this range are treated as NULL (i.e., they will be  ignored  by
       most  aggregates,  or  will  cause  the  result  to  be NULL if -n is given). The low,high thresholds are
       floating point, so use -inf or inf for a single threshold (e.g., range=0,inf to ignore  negative  values,
       or range=-inf,-200.4 to ignore values above -200.4).

       The  maximum  number  of  raster  maps  that  can be processed is given by the user-specific limit of the
       operating system. For example, the soft limits for users are typically 1024 files. The soft limit can  be
       changed  with  e.g.   ulimit -n 4096 (UNIX-based operating systems) but it cannot be higher than the hard
       limit. If the latter is too low, you can as superuser add an entry in:
       /etc/security/limits.conf
       # <domain>      <type>  <item>         <value>
       your_username  hard    nofile          4096
       This will raise the hard limit to 4096 files. Also have a look at the  overall  limit  of  the  operating
       system
       cat /proc/sys/fs/file-max
       which on modern Linux systems is several 100,000 files.

       Use  the  -z  flag  to analyze large amounts of raster maps without hitting open files limit and the file
       option to avoid hitting the size limit of command line arguments.  Note that the  computation  using  the
       file  option  is  slower than with the input option.  For every single row in the output map(s) all input
       maps are opened and closed. The amount of RAM will rise linearly with the number of specified input maps.
       The  input  and  file  options are mutually exclusive: the former is a comma separated list of raster map
       names and the latter is a text file with a new line separated list of raster map names.

EXAMPLES

       Example with MODIS Land Surface Temperature, transforming values from Kelvin * 50 to degrees Celsius:
       r.series.accumulate in=MOD11A1.Day,MOD11A1.Night,MYD11A1.Day,MYD11A1.Night out=MCD11A1.GDD \
             scale=0.02 shift=-273.15 limits=10,30

SEE ALSO

        g.list, g.region, r.series, r.series.interp

       Hints for large raster data processing

REFERENCES

           •   Jones, G.V., Duff, A.A., Hall, A., Myers, J.W., 2010.  Spatial analysis of climate  in  winegrape
               growing regions in the Western United States. Am. J. Enol. Vitic. 61, 313-326.

AUTHORS

       Markus Metz and Soeren Gebbert (based on r.series)

SOURCE CODE

       Available at: r.series.accumulate source code (history)

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       © 2003-2019 GRASS Development Team, GRASS GIS 7.8.2 Reference Manual