This module can use large amounts of system memory when the **-e**
extended statistics flag is used with a very large region setting. If the
region is too large the module should exit gracefully with a memory allocation
error. Basic statistics can be calculated using any size input region.

# define volume g.region n=10 s=0 w=0 e=10 b=0 t=10 res=1 res3=1 -p3 # generate random map r3.mapcalc "random_0_1 = rand(0., 1)" -s # compute univariate statistics, along with extended statistics r3.univar -e map=random_0_1 percentile=98 100% total null and non-null cells: 1000 total null cells: 0 Of the non-null cells: ---------------------- n: 1000 minimum: 0.00053905 maximum: 0.998322 range: 0.997783 mean: 0.513676 mean of absolute values: 0.513676 standard deviation: 0.289969 variance: 0.0840821 variation coefficient: 56.4498 % sum: 513.676463040334 1st quartile: 0.257654 median (even number of cells): 0.524313 3rd quartile: 0.763637 98th percentile: 0.982924 # script style output, along with extended statistics r3.univar -ge map=random_0_1 percentile=98 n=1000 null_cells=0 cells=1000 min=0.000539049520323687 max=0.998322037540536 range=0.997782988020212 mean=0.513676463040334 mean_of_abs=0.513676463040334 stddev=0.289969154194666 variance=0.0840821103843701 coeff_var=56.4497646005434 sum=513.676463040334 first_quartile=0.257654 median=0.524313 third_quartile=0.763637 percentile_98=0.982924

Code is based on r.univar from

Hamish Bowman, Otago University, New Zealand

and Martin Landa

Zonal loop by Markus Metz

*Last changed: $Date$*