NAME

       t.rast.univar   -  Calculates  univariate  statistics  from  the  non-null  cells for each
       registered raster map of a space time raster dataset.

KEYWORDS

       temporal, statistics, raster, time, parallel

SYNOPSIS

       t.rast.univar
       t.rast.univar --help
       t.rast.univar   [-eru]   input=name    [zones=name]     [nprocs=integer]     [output=name]
       [percentile=float[,float,...]]          [where=sql_query]         [region_relation=string]
       [separator=character]   [--overwrite]  [--help]  [--verbose]  [--quiet]  [--ui]

   Flags:
       -e
           Calculate extended statistics

       -r
           Use the raster map regions for univar statistical calculation instead of  the  current
           region

       -u
           Suppress printing of column names

       --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

       zones=name
           Raster map used for zoning, must be of type CELL

       nprocs=integer
           Number of threads for parallel computing
           Default: 1

       output=name
           Name for output file

       percentile=float[,float,...]
           Percentile to calculate (requires extended statistics flag)
           Options: 0-100

       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’

       region_relation=string
           Process only maps with this spatial relation to the current computational region
           Options: overlaps, contains, is_contained

       separator=character
           Field separator character between the output columns
           Special characters: pipe, comma, space, tab, newline
           Default: pipe

DESCRIPTION

       t.rast.univar calculates univariate statistics from the non-null cells for each registered
       raster map of a space time raster dataset.

       By  default  it  returns the name of the map, the semantic label of the map, the start and
       end date of the map and the following values: mean, minimum and maximum vale, mean_of_abs,
       standard deviation, variance, coeff_var, number of null cells, total number of cells.

       Using  the e flag it can calculate also extended statistics: first quartile, median value,
       third quartile and percentile 90.

       If a zones raster map is provided, statistics are computed for  each  zone  (category)  in
       that  input  raster  map.  The  zones  option  does not support space time raster datasets
       (STRDS) but only a single, static raster map.

       Space time raster datasets may contain raster maps with varying spatial  extent  like  for
       example   series   of  scenes  of  satellite  images.  With  the  region_relation  option,
       computations can be limited to maps of the space time raster dataset  that  have  a  given
       spatial relation to the current computational region. Supported spatial relations are:

           •   "overlaps":  process  only  maps  that  spatially  overlap  ("intersect") with the
               current computational region

           •   "is_contained": process only maps that are fully within the current  computational
               region

           •   "contains": process only maps that contain (fully cover) the current computational
               region

EXAMPLE

       Obtain the univariate statistics for the  raster  space  time  dataset  "tempmean_monthly"
       (precision reduced to 2 decimals in this example):
       t.rast.univar -e tempmean_monthly
       id|start|end|mean|min|max|mean_of_abs|stddev|variance|coeff_var|sum|null_cells|cells|first_quartile|median|third_quartile|percentile_90
       2009_01_tempmean@climate_2009_2012|2009-01-01 00:00:00|2009-02-01 00:00:00|3.90|-3.38|7.43|3.95|1.79|3.20|45.91|1977967.31|503233|1010600|2.80|3.92|5.21|6.23
       2009_02_tempmean@climate_2009_2012|2009-02-01 00:00:00|2009-03-01 00:00:00|5.91|-1.82|8.01|5.92|1.63|2.65|27.53|2999555.60|503233|1010600|5.44|6.26|7.07|7.48
       ...
       2012_11_tempmean@climate_2009_2012|2012-11-01 00:00:00|2012-12-01 00:00:00|8.03|1.79|10.91|8.03|1.32|1.73|16.41|4072472.77|503233|1010600|7.49|8.13|8.96|9.48
       2012_12_tempmean@climate_2009_2012|2012-12-01 00:00:00|2013-01-01 00:00:00|8.71|1.76|11.98|8.71|1.72|2.95|19.74|4418403.77|503233|1010600|7.84|8.95|9.99|10.67

SEE ALSO

        t.create, t.info t.create,

AUTHOR

       Sören  Gebbert, Thünen Institute of Climate-Smart Agriculture Stefan Blumentrath, (Support
       for zones, parallel processing, and spatial relations)

SOURCE CODE

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

       Accessed: Thursday Aug 01 11:31:55 2024

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       © 2003-2024 GRASS Development Team, GRASS GIS 8.4.0 Reference Manual