Skip to contents

Irrigation uniformity within units

Source: R/performance_indicators.R
wapor_calc_uniformity.Rd

Per unit: uniformity_cv = 1 - CV (Chukalla proxy), Christiansen CU, and low-quarter DU. Classes come from uniformity_<method> and are applied to uniformity_cv. With irrigation_method = "unknown" only values are returned. Units smaller than min_area_ha are NA.

Usage

wapor_calc_uniformity(
  aeti,
  units,
  id = NULL,
  mask = NULL,
  weights = NULL,
  irrigation_method = c("unknown", "surface", "sprinkler", "pivot", "drip"),
  measures = c("uniformity_cv", "cu", "du_lq"),
  min_area_ha = 1,
  min_cell_fraction = 0.5,
  sd_type = "population"
)

Source

Chukalla et al. (2022); Pitts et al. (1996); Christiansen (1942); Merriam and Keller (1978).

Arguments

aeti

SpatRaster of AETI (or another ET layer).

units

sf polygons, SpatVector, file path, or a single number: block size in metres (projected CRS required).

id

Polygon id column. Default: first attribute, or block_id.

mask, weights

Passed to wapor_zonal_stats().

irrigation_method

One of unknown, surface, sprinkler, pivot, drip.

measures

Statistics to return.

min_area_ha

Units below this valid area (ha) get NA (default 1; heuristic).

min_cell_fraction

Passed to the zonal engine (default 0.5; heuristic).

sd_type

"population" (default) or "sample".

Value

A data frame, one row per unit.

Details

The method standards are for applied water. 1 - CV of ET overstates irrigation uniformity; DU_lq is the closer comparison. Blocks generated from a numeric size measure landscape heterogeneity, not field uniformity.