NDVI2LAI {LAIr}

Derive LAI from NDVI using a set of conversion functions

Description

The function calculates LAI from NDVI values given as a raster or a numeric vector input. The conversion uses the formulas compiled by Bajocco et al. 2022 doi:10.3390/rs14153554. The choice of the equation depends on arguments related to vegetation (category, type, name), or sensor (name, platform, resolution). If no filtering arguments are provided, the function calculate all 199 equations. The function returns a Raster* or a dataframe depending on the input, with the LAI values computed from the available selected conversion equations.

Usage

NDVI2LAI(input,
 ID=NULL,
 biome=NULL,
 category=NULL,
 type=NULL,
 name=NULL,
 sensor=NULL,
 platform=NULL,
 resolution=NULL)

Arguments

input

Raster* or numeric vector. For multi-layer Raster images, the computation is performed for each layer.

ID

Character. Optional parameter to select the function based on its code. For available options, type 'NDVI2LAIeq' (field 'F.ID')

biome

Numeric. Optional integer representing the Biome, sensu Olson and Dinerstein 1998 doi:10.1046/j.1523-1739.1998.012003502.x. For available options, type 'NDVI2LAIeq' (field 'Location.Biome.Code' and 'Location.Biome').

category

Character. Optional parameter to select the Plant Category among: "Crop" "Forest" "Mixed".

type

Character. Optional parameter to select the Plant Type. For available options, type 'NDVI2LAIeq' (field 'Plant.Type')

name

Character. Optional parameter to select the Plant Name. For available options, type 'NDVI2LAIeq' (field 'Plant.Name')

sensor

Character. Optional parameter to select the Sensor Name. For available options, type 'NDVI2LAIeq' (field 'Sensor.Name')

platform

Character. Optional parameter to select the Sensor Platform among: "Satellite" "Field" "Airborne".

resolution

Character. Optional parameter to select the Sensor Resolution Class. For available options, type 'NDVI2LAIeq' (field 'Sensor.ResolutionClass')

Value

A Raster* or a dataframe depending on the input.

See Also

Bajocco et al. (2022). On the Use of NDVI to Estimate LAI in Field Crops: Implementing a Conversion Equation Library. Remote Sens. , 3554, doi: doi:10.3390/rs14153554

Examples

#using a real raster:
file <- system.file('extdata/ndvi-italy.tiff', package='LAIr')
input <- terra::rast(file)
res <- NDVI2LAI(input, category = 'Crop', name = c('Vineyard', 'Barley'), sensor = 'MODIS')
terra::plot(res)

#using a vector
NDVI2LAI(seq(0.5,1,.2), category = 'Mixed', sensor = c('PROBA-V', 'SPOT'))