trapz: Trapezoid integral calculation
In bishun945/FCMm: Fuzzy Cluster Method Based on the Optimized m Value (Fuzzifier)

Description Usage Arguments Details Value Examples

Trapezoid integral calculation

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trapz(wv, x)

trapz2(x)

`wv`	wavelength
`x`	data.frame that need to be trapzed with ncol equal to length of `wv`. Note that the colnames of `x` should be converted to numbers for `trapz`. Do not name them as "Rrs560", "560nm" or so. Just set as "560".

In 2020-11-02, I created an improved version of trapz, say trapz. So better to use trapz as it calculates much faster than before.

A vector presenting the area result.

library(FCMm)
library(magrittr)
library(stringr)
data("Nechad2015")
w <- Nechad2015 %>% names %>%
    str_extract(.,pattern="\\d") %>%
    is.na %>% {!.}
wv <- w %>% names(Nechad2015)[.] %>%
    gsub('X','',.) %>% as.numeric
x <- w %>% Nechad2015[,.]
names(x) <- wv
rm(w)
Area <- trapz(wv, x)
Area2 <- trapz2(x) # the results are indentical to that from trapz