getDesignWgts: Extract design features for FIA inventories
In rFIA: Estimation of Forest Variables using the FIA Database

Description Usage Arguments Details Value Author(s) References See Also Examples

Extracts design information for post-stratified FIA inventories, intended to aid the development of alternative model-based estimators of forest variables. Design information is currently limited to estimation unit land area (AREA_USED) and strata weights (proportion of estimation unit represented by each stratum). This is sufficient to acknowledge design features in an a-spatial model, however, inclusion probabilities and strata boundaries will be necessary to incorporate spatial predictors.

getDesignInfo(db,
              type = c("ALL", "CURR", "VOL", "GROW", "MORT",
                       "REMV", "CHNG", "DWM", "REGEN"),
              mostRecent = TRUE,
              evalid = NULL)

`db`	`FIA.Database` or `Remote.FIA.Database` object produced from `readFIA` or `getFIA`. If a `Remote.FIA.Database`, data will be read in and processed state-by-state to conserve RAM (see details for an example).
`type`	character ('ALL', 'CURR', 'VOL', 'GROW', 'MORT', 'REMV', 'CHNG', 'DWM', 'REGEN'). See Reference Population Evaluation Table Description Type Table in FIADB P2 User Guide (References) for descriptions of evaluation types.
`mostRecent`	logical; if TRUE, returns EVALIDs associated with most recent inventory.
`evalid`	character; unique value which identifies an inventory year and inventory type for a state. If you would like to subset data for an inventory year other than the most recent, use `findEVALID` to look locate this value (see Examples below).

More soon. In the meantime, contact Hunter Stanke at stankehu@msu.edu with questions.

Will generate a data.frame with the columns described below, containing the design information associated one or multiple FIA inventories.

For reference, there are often multiple non-overlapping estimation units within a state, and multiple, non-overlapping, and exhaustive strata within each estimation unit. Estimation unit and strata boundaries vary with inventories (i.e., by reporting year and by inventory type), though multiple inventories may draw from data collected at a single plot visit. Hence, ESTN_UNIT_CN and STRATUM_CN are specific to EVALIDs (or alternatively, the combination of STATE, YEAR, and EVAL_TYP, for all states except Texas). However, a single PLT_CN may be associated with multiple ESTN_UNIT_CNs and STRATUM_CNs.

STATECD: unique identifier for states.
YEAR: reporting year associated with estimates (END_INVYR from POP_EVAL).
EVAL_TYP: an identifier describing the type of evaluation. For example, "EXPVOL" represents current volume inventories.
EVALID: unique identifier that represents the population used to produce a type of estimate.
ESTN_UNIT_CN: unique identifier for estimation unit.
AREA_USED: area of estimation unit used for population estimation.
STRATUM_CN: unique identifier for strata.
STRATUM_WGT: nproportion of estimation unit area (AREA_USED) that is occupied by a particular stratum. Defined on the range (0,1].
pltID: unique identifier for plot location.
PLT_CN: unique identifier for plot visit.

Hunter Stanke and Andrew Finley

FIA Database User Guide: https://www.fia.fs.fed.us/library/database-documentation/

findEVALID

## Load the Rhode Island subset included w/ rFIA
data(fiaRI)

## Extract the design information associated with the most recent current
## volume inventory in the state (2018 for this subset)
wgts <- getDesignInfo(db = fiaRI, mostRecent = TRUE, type = 'VOL')