Combines and plots spectra (by taking the average and the standard deviation,
for example) according to an index or a vector of identities.

aggplot(
rspecdata,
by = NULL,
FUN.center = mean,
FUN.error = sd,
lcol = NULL,
shadecol = NULL,
alpha = 0.2,
legend = FALSE,
...
)

## Arguments

rspecdata |
(required) a data frame, possibly of class `rspec` , which
contains a column containing a wavelength range, named 'wl', and spectra
data in remaining columns. |

by |
(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)` . |

FUN.center |
the function to be applied to the groups of spectra,
calculating a measure of central tendency (defaults to `base::mean()` ). |

FUN.error |
the function to be applied to the groups of spectra,
calculating a measure of variation (defaults to `stats::sd()` ). |

lcol |
colour of plotted lines indicating central tendency. |

shadecol |
colour of shaded areas indicating variance measure. |

alpha |
transparency of the shaded areas. |

legend |
automatically add a legend. |

... |
additional graphical parameters to be passed to plot. |

## Value

Plot containing the lines and shaded areas of the groups of spectra.

## References

Montgomerie R (2006) Analyzing colors. In: Hill G, McGraw K (eds)
Bird coloration. Harvard University Press, Cambridge, pp 90-147.

## Author

Rafael Maia rm72@zips.uakron.edu,
Chad Eliason cme16@zips.uakron.edu

## Examples

aggplot(sicalis, bysic, shadecol = spec2rgb(sicalis), lcol = 1)