Map spectra to new wavelength values.
This function returns the result of interpolating spectral data from the original set of wavelengths to a new one.
interpolate_wl(x, w.length.out, fill, length.out, ...) ## Default S3 method: interpolate_wl(x, w.length.out, fill, length.out, ...) ## S3 method for class 'generic_spct' interpolate_wl(x, w.length.out = NULL, fill = NA, length.out = NULL, ...) ## S3 method for class 'generic_mspct' interpolate_wl( x, w.length.out = NULL, fill = NA, length.out = NULL, ..., .parallel = FALSE, .paropts = NULL )
x |
an R object |
w.length.out |
numeric vector of wavelengths (nm) |
fill |
a value to be assigned to out of range wavelengths |
length.out |
numeric value |
... |
not used |
.parallel |
if TRUE, apply function in parallel, using parallel backend provided by foreach |
.paropts |
a list of additional options passed into the foreach function when parallel computation is enabled. This is important if (for example) your code relies on external data or packages: use the .export and .packages arguments to supply them so that all cluster nodes have the correct environment set up for computing. |
If length.out it is a numeric value, then gives the number of rows in the
output, if it is NULL, the values in the numeric vector w.length.out are used.
If both are not NULL then the range of w.length.out and length.out are
used to generate a vector of wavelength. A value of NULL for fill prevents
extrapolation.
A new spectral object of the same class as argument spct.
default: Default for generic function
generic_spct: Interpolate wavelength in an object of class
"generic_spct" or derived.
generic_mspct: Interpolate wavelength in an object of class
"generic_mspct" or derived.
The default fill = NA fills extrapolated values with NA. Giving NULL as
argument for fill deletes wavelengths outside the input data range from the
returned spectrum. A numerical value can be also be provided as fill. This function calls
interpolate_spectrum for each non-wavelength column in the input spectra object.
interpolate_wl(sun.spct, 400:500, NA) interpolate_wl(sun.spct, 400:500, NULL) interpolate_wl(sun.spct, seq(200, 1000, by=0.1), 0) interpolate_wl(sun.spct, c(400,500), length.out=201)
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