Places new spectra on the best-matching unit of a map fitted by som(),
with their quantization error, and flags the spectra that fit no unit.
Usage
# S3 method for class 'specproc_som'
predict(object, newdata, ...)Arguments
- object
A map fitted by
som().- newdata
A numeric matrix or data frame of spectra, with the variables of the training data.
- ...
Not used.
Value
A tibble with one row per spectrum: its best-matching unit, the
coordinates x and y of the unit on the map, the quantization error
qe, and novel, TRUE when the error exceeds the cut-off of the
training spectra (the spectrum fits no known group).
Examples
data(forageLIBS)
# the Na I and K I resonance lines
wl <- suppressWarnings(as.numeric(names(forageLIBS)))
spectra <- forageLIBS[which((wl > 585 & wl < 595) | (wl > 760 & wl < 780))]
fit <- som(spectra[1:300, ])
head(predict(fit, spectra[301:368, ]))
#> # A tibble: 6 × 5
#> unit x y qe novel
#> <int> <dbl> <dbl> <dbl> <lgl>
#> 1 23 1 2.73 6712. FALSE
#> 2 6 6 1 16826. TRUE
#> 3 38 5.5 3.60 6112. FALSE
#> 4 13 2.5 1.87 4720. FALSE
#> 5 3 3 1 5178. FALSE
#> 6 45 1 4.46 9293. FALSE