| surveySpectra {ChemoSpec} | R Documentation |
Compute and plot various measures of central tendency and
spread for a Spectra object. Several different measures/spreads
are available. These are useful as an overview of where a data set varies
the most.
surveySpectra(spectra, method = c("sd", "sem", "sem95", "mad", "iqr"),
by.gr = TRUE, ...)
surveySpectra2(spectra, method = c("sd", "sem", "sem95", "mad", "iqr"),
lab.pos = 0.9 * max(spectra$freq), ...)
spectra |
An object of S3 class |
method |
Character. One of |
by.gr |
Logical, indicating if the analysis is to be done by group or
not. Applies to |
... |
Additional parameters to be passed to the plotting routines. |
lab.pos |
Numeric, giving the frequency where the label should be drawn.
Applies to |
For surveySpectra the method choice works as follows: sd plots
the mean spectrum +/- the standard deviation, sem plots the mean
spectrum +/- the standard error of the mean, sem95 plots the mean
spectrum +/- the standard error at the 95 percent confidence interval,
mad plots the median spectrum +/- the median absolute deviation, and
finally, iqr plots the median spectrum + the upper hinge and - the
lower hinge.
For surveySpectra2, the spectra are mean centered and plotted. Below
that, the relative summary statistic is plotted, offset, but on the same
scale.
None; side effect is a plot
surveySpectra: Spectral survey emphasizing mean or median spectrum, optionally by group.
surveySpectra2: Spectral survey emphasizing variation among spectra.
Bryan A. Hanson, DePauw University.
https://github.com/bryanhanson/ChemoSpec
data(SrE.IR) myt <- expression(bolditalic(Serenoa)~bolditalic(repens)~bold(Extract~IR~Spectra)) surveySpectra(SrE.IR, method = "iqr", main = myt) surveySpectra2(SrE.IR, method = "iqr", main = myt)