point_data: Create objects of class 'point_data'

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

Description

The function point_data creates point data objects. Such objects store aggregated tree-level information by sample and sample point location. The function is only used internally by sum_data.

Usage

point_data(data, r_design, r_design_parm)

Arguments

data	A data.table object holding aggregated tree data together with identifiers that indicate the sample and the point location.
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.

Details

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

• id_sample

• id_point

• variable

When k_tree sampling was applied at the individual sample locations, there are four approximations for expanding the target variables listed under the variable column (see sum_k_tree). The respective column names are:

• Prodan

• Eberhardt

• d_mean

• a_mean

For other response designs (e.g., angle count, fixed area), expansion to per hectare values is based on known expansion factors that can be derived from the response design parameters and not on approximations. In such cases, the expanded values are listed under ef_ana, meaning analytically derived expansion factors.

The last column is_edge indicates whether some sort of edge correction was performed at the respective sample point or not.

Value

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

2. $r_design

3. $r_design_parm

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