Package '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'))

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Dataset of empirical functions to convert NDVI to LAI in crops, forests and mixed vegetation.

Description

Dataset of empirical functions to convert NDVI to LAI, compiled by Bajocco et al. 2022. It contains some arguments used by the NDVI2LAI() function to subset the conversion equations.

Usage

NDVI2LAIeq

Format

A data frame with 199 rows and 19 columns:

Function.ID

Equation name.

F.ID

Function ID code varying between F001 and F199.

Plant.Category

Plant categories: "Crop" "Forest" "Mixed".

Plant.Type

Plant types: "Permanent" "Summer" "Winter" "Forest" "Perennial" "Mixed".

Plant.Name

Plant names: "Vineyard" "Maize" "Wheat" "Barley" "Forest" "Poplar" "Soybean" "Rice" "Sunflower" "Sugarcane" "Pasture" "Eucalypt" "Mixed".

Location.Biome.Code

The Biome code of the experimental location, following Olson & Dinerstein (1998) doi:10.1046/j.1523-1739.1998.012003502.x

Location.Biome

The Biome name of the experimental location: "Mediterranean Forests, Woodlands & Scrub" "Temperate Grasslands, Savannas & Shrublands" "Temperate Broadleaf & Mixed Forests""Deserts & Xeric Shrublands" "Tropical & Subtropical Dry Broadleaf Forests" "Montane Grasslands & Shrublands" "Tropical & Subtropical Grasslands, Savannas & Shrublands" "Tropical & Subtropical Moist Broadleaf Forests".

Location.Country

Country.

Sensor.Name

Sensor Names: "IKONOS" "MODIS" "Spectroradiometer" "Landsat" "AVHRR" "SPOT" "UAV" "Hyperion" "RapidEye" "Sentinel-2" "MultispectralCamera" "Quickbird" "WorldView2" "WorldView3" "Pleiades-1A" "GeoEye1" "AISA" "GF1" "HJ" "PROBA-V" "SPOT-VGT" "AWiFS" "BJ1"

Sensor.Platform

Sensor Platform: "Satellite" "Field" "Airborne".

Sensor.Resolution

Spatial resolution of the sensor.

Sensor.ResolutionClass

Sensor spatial resolution class: "High" "Low" "Very-High" "Moderate".

Sensor.PixelSize

Pixel size.

Equation.R2

Coefficient of determination of the equation (when available).

Equation.Codomain

The set of the function's possible outputs.

Equation.Domain

The set of inputs accepted by the function.

Equation.MathematicalForm

Mathematical form of the function: "Linear" "Logarithmic" "Exponential" "Polynomial" "Power".

Reference.DOI

DOI of the publication.

Function.call

Conversion formula used by the NDVI2LAI()

Source

doi:10.3390/rs14153554

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