response: Objects of class response

In AWF-GAUG/fisim: Forest Inventory Simulator (fisim) is a package for simulating response and samplign designs common in forest inventories.

Description

The function response creates response design objects that store the results of a particular response design that was applied at given sample locations to some tree population. The function is only used internally by the functions that apply the particular response designs: fixed_area, k_tree, angle_count.

Usage

response(data, r_design, r_design_parm)

Arguments

data	A data.table object holding identifiers for the sample and respective point locations and row indices that indicate which population elements are selected into the sample.
r_design	A character string indicating the type of the response design. One of the following: "fixed_area", "k_tree", "angle_count".
r_design_parm	A response design specific parameter of type numeric. For "fixed_area" the plot radius in meter; for "k_tree" the number of trees closest to the sample location; for "angle_count" the basal area factor.
ef	The expansion factor, i.e., the factor that is used to prorate tree attributes to per hectare values (the inverse of the inclusion probabilities). Provided by the particular response design functions.
ef_alt1	Alternative expansion factor that may be applied when using k-tree sampling.
ef_alt2	A third alternative expansion factor approximation for k-tree sampling

Details

The data.table object (data) should have the following columns:

• id_sample

• id_point

• s

• ef

Some response designs (currently only k_tree), may add additional alternative expansion factors as optional approximations, where unbiased estimators are missing or difficult to derive.

Value

An object of class response. A named list with the following entries:

• $data A data.table object as described above.

• $r_design

• $r_design_parm

AWF-GAUG/fisim documentation built on May 28, 2019, 11:02 a.m.