l4_get_xvar: Get xvar information from a list of GEDI Level 4 file path

In VangiElia/GEDI4R: What the Package Does (One Line, Title Case)

Get xvar information from a list of GEDI Level 4 file path

Description

Get GEDI L4 xvar information from h5 file format.These information are related to the Level 2A predictors used to obtain the AGBD estimates and can be used to reconstruct L2A metrics used for the estimation and the AGBD estimates itself. See here for more documentation on GEDI L4 data. The function use the snowfall package to get data in parallel. There could be memory allocation problems for an high number of file path.

Usage

l4_get_xvar(
  gediL4_path,
  ncore = parallel::detectCores() - 1,
  merge = T,
  source = F
)

Arguments

gediL4_path	Character path to GEDI level 4A h5 file.
ncore	Numeric: numbers of core to be used if the maximum core available is less than the length of gediL4_path Default to the number of cores available minus one.
merge	Logical: if TRUE (default) the resulted list will be merged with rbind. Ignored if length(gediL4_path)==1
source	Logical: if TRUE and merge=TRUE add a column with the source path of each observation.Ignored if length(gediL4_path)==1, and if merge=FALSE

Details

Part of columns in the output are also present in the output of l4_getmulti. The other columns are described in the chapter "data characteristics" on this page. Relevant columns are:

• rh_index.x: Vector of the height percentile associated with the given RH metric in GEDI L2A.

• predictor_is.x: The variable predictor_id provides a mapping between rh_index and par

• par.x: The vector par contains coefficients of the linear model used to predict AGBD, where the first element is the intercept and subsequent elements are slope coefficients

• V.x : Values of scaled and transformed GEDI l2A RH metrics entered in the selected model to estimate AGBD

For more information on these data see the Frequently asked question here. Note that by default the function will drop all footprint in which agbd<0. These observations are considered sensor errors.

Value

an S4 object of class data.table.

VangiElia/GEDI4R documentation built on April 8, 2023, 6:13 p.m.