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Create Allocation Parameters Table

Source: R/alloc_params_t.R
alloc_params_t.Rd

Creates an alloc_params_t table for storing allocation parameters for each transition and run. This function creates an empty table with the proper structure for storing allocation parameters.

Usage

as_alloc_params_t(x)

# S3 method for class 'alloc_params_t'
print(x, nrow = 10, ...)

isometry_from_elongation(
  elongation,
  curve = data.frame(isometry = c(0, 0.25, 0.5, 0.75, 1, 1.2, 1.5, 2), elongation =
    c(0.34, 0.334, 0.333, 0.328, 0.32, 0.172, 0.171, 0.17)),
  clamp = TRUE
)

compute_alloc_params_single(lulc_ant, lulc_post, id_lulc_ant, id_lulc_post)

create_alloc_params_t(self, n_perturbations = 5L, sd = 0.05)

Arguments

x

A list or data.frame coercible to a data.table

nrow

see data.table::print.data.table

...

passed to data.table::print.data.table

elongation

Numeric vector of elongation values

curve

Data frame with columns isometry and elongation defining the mapping curve

clamp

Logical, whether to clamp values outside the curve range to min/max or to return NA

lulc_ant

SpatRast with LULC data for the anterior (earlier) period

lulc_post

SpatRast with LULC data for the posterior (later) period

id_lulc_ant

Integer ID of the anterior LULC class

id_lulc_post

Integer ID of the posterior LULC class

self

evoland_db instance to query

n_perturbations

Integer number of randomly perturbed parameter sets to create per transition (default: 5)

sd

Numeric standard deviation for random perturbations (default: 0.05)

Value

A data.table of class "alloc_params_t" with columns:

  • id_run: Foreign key to runs_t

  • id_trans: Foreign key to trans_meta_t

  • mean_patch_size: Mean area of new patches (in cell units)

  • patch_size_variance: Standard deviation of patch area

  • patch_isometry: Measure of patch shape regularity

  • frac_expander: Fraction of transition cells adjacent to existing patches

  • frac_patcher: Fraction of transition cells forming new patches

  • similarity: Similarity metric for allocation parameters, see calc_fuzzy_similarity() and eval_alloc_params_t()

A named list with allocation parameters:

  • mean_patch_size: Mean area of patches (hectares)

  • patch_size_variance: Standard deviation of patch area (hectares)

  • patch_isometry: Measure of patch shape regularity (0-1)

  • frac_expander: Fraction of transition cells adjacent to old patches in [0, 1]

  • frac_patcher: Fraction of transition cells forming new patches in [0, 1]

Methods (by generic)

  • print(alloc_params_t): Print a alloc_params_t object, passing params to data.table print

Functions

  • isometry_from_elongation(): Map patch elongation to Dinamica "isometry" patcher parameter, c.f. fig. 3.10 in Mazy, 2022 https://theses.hal.science/tel-04382012v1

  • compute_alloc_params_single(): Compute allocation parameters for a single transition and period pair. This is an internal function used by create_alloc_params_t.

  • create_alloc_params_t(): Create allocation parameters for each transition by estimating patch shape and expansion/patch ratio from observed periods, then aggregate and perturb parameters for use in runs.