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Flag implausible year-on-year jumps in a per-unit extent

Source: R/admin_shares_seam.R
check_extent_jumps.Rd

Run check_series_jumps() on extent_ha per unit series, the check the plan's seam section asks for before an extent modulates a share. WHEP repairs LUH2's isolated single-year cropland collapses nationally (.fix_luh2_crop_collapse(), R/build_production.R:627-695); the same collapse reaches a unit series unrepaired, where it would propagate into every earlier back-cast year through the growth chain.

The scan covers whatever years extent carries. backcast_admin_shares() calls it on the back-cast window alone – t0 and everything before it, the years the modulation actually reads – so a jump after the seam is not a reason to refuse a back-cast.

Usage

check_extent_jumps(
  extent,
  ratio_bounds = c(0.55, 1.6),
  min_value = 0,
  verbose = FALSE
)

Arguments

extent

A per-unit extent table as returned by aggregate_unit_extent(). Every column that is not year, extent_ha or extent_basis identifies the series.

ratio_bounds

Length-2 numeric c(low, high) plausible band for the ratio of consecutive years, passed to check_series_jumps(), whose own default it inherits.

min_value

Minimum extent both members of a pair must exceed to be flagged, passed to check_series_jumps().

verbose

Logical, passed to check_series_jumps(). Default FALSE, so a guard inside a back-cast stays quiet.

Value

The check_series_jumps() flags tibble: the series key columns, year, prev_value, value, ratio and allowlisted.

Examples

extent <- tibble::tibble(
  area_code = 900L,
  level_polity_code = "A1",
  level = 1L,
  year = 1900:1903,
  extent_ha = c(1000, 1010, 5, 1020),
  extent_basis = "cropland_ha"
)
check_extent_jumps(extent)
#> # A tibble: 2 × 8
#>   area_code level_polity_code level  year prev_value value     ratio allowlisted
#>       <int> <chr>             <int> <int>      <dbl> <dbl>     <dbl> <lgl>      
#> 1       900 A1                    1  1902       1010     5   0.00495 FALSE      
#> 2       900 A1                    1  1903          5  1020 204       FALSE