r.series.accumulate(1grass) GRASS GIS User's Manualr.series.accumulate(1grass)
NAME
r.series.accumulate - Makes each output cell value a accumulationfunc-
tion 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 de-
fined
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 (north-
ern 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 au-
tomatically 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 re-
sult 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 lim-
its 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 su-
peruser 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 op-
tion 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 sepa-
rated 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)
Accessed: unknown
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GRASS 7.8.7 r.series.accumulate(1grass)
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