Ubuntu Manpage: r.series.accumulate - Makes each output cell value a accumulationfunction of the values

Provided by: grass-doc_7.8.2-1build3_all

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

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