Combines spectra (by taking the average, for example) according to
an index or a vector of identities.
aggspec(rspecdata, by = NULL, FUN = mean, trim = TRUE)
(required) data frame, possibly of class
containing the spectra to be manipulated. If it contains a wavelength column
named "wl", that column will be ignored.
(required) either a single value specifying the range of spectra within
the data frame to be combined (for example,
by = 3 indicates the function
will be applied to groups of 3 consecutive columns in the spectra data frame);
a vector containing identifications for the columns in the spectra data frame
(in which case the function will be applied to each group of spectra sharing the
same identification); or a list of vectors, e.g.,
by = list(sex, species).
the function to be applied to the groups of spectra. (defaults to
TRUE (default), the function will try to identify and
remove numbers at the end of the names of the columns in the new rspec object.
A data frame of class
rspec containing the spectra after applying the aggregating function.
Montgomerie R (2006) Analyzing colors. In: Hill G, McGraw K (eds)
Bird coloration. Harvard University Press, Cambridge, pp 90-147.
# Average every two spectra
teal.sset1 <- aggspec
, by = 2
# Create factor and average spectra by levels 'a' and 'b'
ind <- rep
), times = 6
teal.sset2 <- aggspec
, by = ind