waveformlidar (version 1.2.0)

integral: integral

Description

The function allows you to calculate the integral of intensity from ground part, vegetation part, sum of them and ratio between vegation integral and total integral with user-defined vegetation and ground boundary.

Usage

integral(
  y,
  smooth = TRUE,
  rescale = TRUE,
  thres = 0.2,
  width = 3,
  tr = 1,
  dis = 20
)

Arguments

y

is the waveform intensities. If you have other information, you should delete these intensites before you run this function .

smooth

is tell whether you want to smooth the waveform to reduce the effect of some obvious noise. Default is TRUE.

rescale

is to determine whether you want to rescale the waveform intensity or not. Here we used the minimum intensity of each waveform to conduct rescaling. Default is using rescaling.

thres

is to determine if the detected peak is the real peak whose intensity should be higher than threshold*maximum intensity. Default is 0.2.

width

width of moving window.Default is 3, must be integer between 1 and n.This parameter ONLY work when the smooth is TRUE.

tr

the temporal resolution of waveform.Default is 1 ns. Must be integer from 1 to n.

dis

the distance from last echo (assumed ground) which determine the boundary between ground and vegetation. Default is 20 ns which equals to 3 m (20*0.15*1).This means the ground part signals are from the assumed ground location to 20 ns above or the signals of vegetation are from waveform begining to 3 m above ground.

Value

return the integral of waveform intensity for the ground, vegetation parts, the whole waveform above ground and the integral ration betwwen vegetation and the whole waveform .

Examples

# NOT RUN {
data(return)
x<-return[1,]
##if we kept everything as default, before you use this function, you need to know the
## temporal resolution of waveform, default is 1 ns.

##for one peak, it generaly not make too much sense since generally only ground was
##present in this case.

r1<-integral(x)

#if you didn't want to smooth,
r2<-integral(x,smooth=FALSE)

##you also can define the boundary between vegetation and ground by assign adjusting dis
#if we assign 15, it means vegetation starts at 2.25 (15*1*0.15) m above the last echo.

r3<-integral(x,dis=15)
# when it comes to the waveform with several peaks
xx<-return[182,]

rr1<-integral(xx)

# }