BandMath: BandMath

In tommasojulitta/FieldSpectroscopyDP: R package for processing fieldspectroscopy data

Description

Compute the mathematic combination of n bands according to a specified formula and to a specified band convlution (average or gaussian)

Usage

BandMath(wl, spectrum, expr, bands, fun = "mean")

Arguments

wl	numeric vector: wavelength vector
spectrum	numeric vector or dataframe: spectrum to analyze
expr	expression containing the arithmetic operations between bands. Incremental alphabetich letter are used.
bands	numeric data.frame: center wavelength and fwhm of each bands to be used. Each row of the data.frame is called incremettally considering alphabetic letters. First row a, ..., 26th row z.
fun	function for the band value calculation (e.g. mean, gaussian)

Value

numeric vector or value containing the spectral index selected.

Author(s)

Tommaso Julitta, Mirco Migliavacca, Thomas Wutzler

Examples

  





data("FloX_data")


data("up_coeffa")


data("dw_coeff")


data("wl_FloX")





#Get Target Radiance 


L<-GetRadiance(DNSignal=FloX_data$L-FloX_data$dcL,IntegrationTime=FloX_data$IT_L/1000,RadCalCoeff=dw_coeff)


#Get Solar Radiance 


E<-GetRadiance(DNSignal=FloX_data$E-FloX_data$dcE,IntegrationTime=FloX_data$IT_E/1000,RadCalCoeff=up_coeff)


#Get Reflectance


Ref<-GetReflectance(UpwellingRadiance = L,DownwellingRadiance=E)





#Define Index expression


expressionND<-"(a-b)/(a+b)"


#Define Index band


ND_bands<-data.frame(cwl= c(780,680),fwhm=c(5,5,5,5))


#Compute index


ND<-BandMath(wl=wl_FloX,spectrum=Ref,expr=parse(text=expressionND),ND_bands,fun="mean")


ND_gaus<-BandMath(wl=wl_FloX,spectrum=Ref,expr=parse(text=expressionND),ND_bands,fun="gaussian")





#plot results    


x11()


par(mar=c(5,5,2,2))


plot(ND,pch=20,xlab="N. measurements",ylab="NDVI - 780nm & 680nm",ylim = c(-1,1),cex=3,col="dark green")


points(ND_gaus,pch=20,col="red")

tommasojulitta/FieldSpectroscopyDP documentation built on March 12, 2020, 1:42 p.m.