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: Friday Apr 04 01:21:14 2025

       Main index | Temporal index | Topics index | Keywords index | Graphical index | Full index

       © 2003-2025 GRASS Development Team, GRASS GIS 8.4.1 Reference Manual

GRASS 8.4.1                                                                                t.rast.univar(1grass)