R: Calculate spectral values at a different set of wavelengths

interpolate_spectrum {photobiology} | R Documentation

## Calculate spectral values at a different set of wavelengths

### Description

Interpolate/re-express spectral irradiance (or other spectral quantity) values at new wavelengths values. This is a low-level function operating on numeric vectors and called by higher level functions in the package, such as mathematical operators for classes for spectral data.

### Usage

    interpolate_spectrum(w.length.in, s.irrad, w.length.out, fill = NA, ...)

### Arguments

`w.length.in` | numeric vector of wavelengths (nm).
`s.irrad` | a numeric vector of spectral values.
`w.length.out` | numeric vector of wavelengths (nm).
`fill` | a value to be assigned to out of range wavelengths.
`...` | additional arguments passed to `spline()`.

### Value

a numeric vector of interpolated spectral values.

### Note

The current version of interpolate uses `spline` if fewer than 25 data points are available. Otherwise it uses `approx`. In the first case a cubic spline is used, in the second case linear interpolation, which should be faster.

### See Also

`splinefun`.

Other low-level functions operating on numeric vectors.: `as_energy`, `as_quantum_mol`, `calc_multipliers`, `div_spectra`, `energy_irradiance`, `energy_ratio`, `insert_hinges`, `integrate_xy`, `irradiance`, `l_insert_hinges`, `oper_spectra`, `photon_irradiance`, `photon_ratio`, `photons_energy_ratio`, `prod_spectra`, `s_e_irrad2rgb`, `split_energy_irradiance`, `split_photon_irradiance`, `subt_spectra`, `sum_spectra`, `trim_tails`, `v_insert_hinges`

### Examples

    my.w.length <- 300:700
    with(sun.data, interpolate_spectrum(w.length, s.e.irrad, my.w.length))

[Package photobiology version 0.9.21 Index]