Melts the spectra data of a Spectra object and returns it as wide format.
This function is very useful when wanting to plot spectra using the lattice or ggplot2 packages
melt_spectra(obj, attr=NULL, ...) ## S4 method for signature 'SpectraDataFrame' melt_spectra(obj, attr = NULL, ...)
obj |
an object of class |
attr |
vector of id variables against which the spectra will be melted (see |
... |
further arguments passed to or from other methods |
x=Spectra
melt_spectra(obj, ...)
obj |
A Spectra object |
|
... |
Ignored | |
x=SpectraDataFrame
melt_spectra(obj, attr=NULL, ...)
obj |
A SpectraDataFrame object |
|
attr |
Character, the name of an attribute in the object data to split the spectra against. | |
... |
Ignored | |
Pierre Roudier pierre.roudier@gmail.com
Hadley Wickham (2011). The Split-Apply-Combine Strategy for Data Analysis. Journal of Statistical Software, 40(1), 1-29. URL http://www.jstatsoft.org/v40/i01/.
# Loading example data data(australia) spectra(australia) <- sr_no ~ ... ~ 350:2500 # Simple melt r <- melt_spectra(australia) head(r) ## Not run: # Melt against some factor (or continuous data), and plot # using ggplot2 # Create some factor australia$fact <- sample( LETTERS[1:3], size = nrow(australia), replace = TRUE ) r <- melt_spectra(australia, attr = 'fact') # Create plot library(ggplot2) p <- ggplot(r) + geom_line(aes(x=wl, y=nir, group=id, colour=fact)) + theme_bw() print(p) ## End(Not run)
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