---
title: "User Guide: 0 The R for Photobiology Suite"
subtitle: "Photobiology-related computations in R"
author: "Pedro J. Aphalo"
date: "Built: `r Sys.Date()`"
output: 
  rmarkdown::html_vignette:
    toc: yes
vignette: >
  %\VignetteIndexEntry{User Guide: 0 The R for Photobiology Suite}
  %\VignetteEncoding{UTF-8}
  %\VignetteEngine{knitr::rmarkdown}
editor_options: 
  markdown: 
    wrap: 72
---

The citation for the suite is given by

```{r}
print(citation('photobiology'), style = "textVersion")
```

## Introduction

Package 'photobiology' is at the core of a suite of packages for
analysis and plotting of data relevant to photobiology (described at
<https://www.r4photobiology.info/>). The accompanying packages provide
data and definitions that are to a large extent application-area
specific while the functions in the package 'photobioloy' are widely
useful in photobiology and in radiation quantification in geophysics and
meteorology. Package 'photobiology' has its main focus in the
characterization of the light environment in a biologically relevant
manner and in the manipulation of spectral data to simulate
photo-physical, photo-chemical and photo-biological interactions and
responses. In addition it implements the algorithms of Jean Meeus for
the position of the sun, as this and derived quantities like day- and
night length are important for most organisms.

Data exchange with packages 'pavo', 'colorSpec' and 'hyperSpec' is
supported. The focus of package 'pavo' (Maia et al. 2003) is on color
perception by animals and assessment of animal coloration. The focus of
package 'colorSpec' (Davis 2019) is on color-related computations:
"Calculate with spectral properties of light sources, materials,
cameras, eyes, and scanners." The focus of package 'hyperSpec' (Beleites
and Sergo) is the handling of hyperspectral data sets, such as spectral
images and time series of spectra.

Because of their different focus, these packages mostly complement each
other, in spite of some overlap and differences in approach or even, in
philosophy about data handling.'

### References

Aphalo, P. J., Albert, A., Björn, L. O., McLeod, A. R., Robson, T. M.,
Rosenqvist, E. (Eds.). (2012). *Beyond the Visible: A handbook of best
practice in plant UV photobiology* (1st ed., p. xx + 174). Helsinki:
University of Helsinki, Department of Biosciences, Division of Plant
Biology. ISBN 978-952-10-8363-1 (PDF), 978-952-10-8362-4 (paperback).
Open access at <https://doi.org/10.31885/9789521083631>.

Aphalo, Pedro J. (2015) The r4photobiology suite. *UV4Plants Bulletin*,
2015:1, 21-29. (<https://doi.org/10.19232/uv4pb.2015.1.14>).

Davis G (2019). *A Centroid for Sections of a Cube in a Function Space,
with application to Colorimetry.* *ArXiv e-prints*. 1811.00990,
(<https://arxiv.org/abs/1811.00990>).

Maia, R., Eliason, C. M., Bitton, P. P., Doucet, S. M., Shawkey, M. D.
(2013) pavo: an R package for the analysis, visualization and
organization of spectral data. *Methods in Ecology and Evolution*,
4(10):906-913. (<https://doi.org/10.1111/2041-210X.12069>).

## Packages in the suite

The core package in this suite is called
['**photobiology**'](https://docs.r4photobiology.info/photobiology/) and
all other packages in the suite depend on it. Other specialized packages
for quantification of ultraviolet-, visible- and infra-red radiation
(['**photobiologyWavebands**'](https://docs.r4photobiology.info/photobiologyWavebands/)),
properties of plant photoreceptors and other plant photobiology related
calculations
(['**photobiologyPlants**'](https://docs.r4photobiology.info/photobiologyPlants/)),
example spectral data for filters and objects
(['**photobiologyFilters**'](https://docs.r4photobiology.info/photobiologyFilters/)),
lamps
(['**photobiologyLamps**'](https://docs.r4photobiology.info/photobiologyLamps/)),
LEDs
(['**photobiologyLEDs**'](https://docs.r4photobiology.info/photobiologyLEDs/)),
sunlight
(['**photobiologySun**'](https://docs.r4photobiology.info/photobiologySun/)),
light sensors
(['**photobiologySensors**'](https://docs.r4photobiology.info/photobiologySensors/))
and for exchange of data in *foreign* formats
(['**photobiologyInOut**'](https://docs.r4photobiology.info/photobiologyInOut/))
are part of the suite. One additional package,
(['**ggspectra**'](https://docs.r4photobiology.info/ggspectra/)),
implements facilities for plotting spectral data by extending package
'ggplot2'. Two additional packages (['**rOmniDriver**'](https://docs.r4photobiology.info/rOmniDriver/)) and (['**ooacquire**'](https://docs.r4photobiology.info/ooacquire/)) make it possible to acquire spectral data by controlling _Ocean Insight/Ocean Optics_ spectrometers from within R.

| Package                     | Provides                                                                                                                                                                                                |
|------------------------------------|------------------------------------|
| 'photobiology'              | Core classes, methods and functions                                                                                                                                                                     |
| 'photobiologyWavebands'     | Definitions of standardized and frequently used wavelength band definitions and spectral weighting functions.                                                                                           |
| 'photobiologyPlants'        | Methods, functions and data for plants and vegetation.                                                                                                                                                  |
| 'photobiologyInOut'         | Exchange of data within R and using different proprietary and standard-based formats.                                                                                                                   |
| 'photobiologyLamps'         | Spectral emission and other data for various lamp types.                                                                                                                                                |
| 'photobiologyLEDs'          | Spectral emission and other data for various LEDs and LED arrays.                                                                                                                                       |
| 'photobiologySensors'       | Spectral response and other data for various UV, VIS and NIR sensors.                                                                                                                                   |
| 'photobiologySun'           | Spectral irradiance and other data for sunlight. Both measured and standard definitions for ground level and top of the atmosphere.                                                                     |
| 'photobiologyFilters'       | Spectral transmittance and spectral reflectance data for different materials including optical filters. Spectral data on refractive index.                                                              |
| 'ggspectra'                 | Extensions to package 'ggplot2' for easier plotting of spectral data, including `autoplot()` and `ggplot()` methods for the classes defined in package 'photobiology' and scales, geoms and statistics. |
| 'oocquire' (Not in CRAN)    | Data acquision and control of Ocean Optics (now Ocean Insight) spectrometers.                                                                                                                           |
| 'rOmniDriver' (Not in CRAN) | Interface to OmniDriver drivers for communication with spectrometers from Ocean Optics (now Ocean Insight)                                                                                              |

For additional information on these and other packages by the author
please visit (<https://www.r4photobiology.info>) for news, and
check the menue entry **R Packages > Checks and Issues** for current status
and links to on-line documentation and public Git repositories. Each
package has its own public Git repository at my [GitHub account](<https://github.com/aphalo/>) from
where the source code of the current and earlier versions can be cloned
or forked.

## Acknowledgements

This work was funded in part by the Academy of Finland (decision
252548), and done when the author was employed at the University of
Helsinki, Finland. COST Action FA9604 'UV4Growth' facilitated
discussions and exchanges of ideas that lead to the development of this
package. The contributions of Andy McLeod, Lars Olof Björn, Nigel Paul,
Lasse Ylianttila, Glen Davis, Agnese Fazio, T. Matthew Robson and Titta
Kotilainen were specially significant. Other members of the UV4Plants
Association (<https://www.uv4plants.org/>) and participants in workshops
and training events contributed both problems in need of being solved
and solutions to implement.

Tutorials by Hadley Wickham and comments on my presentation at
*UseR!2015* allowed me to significantly improve the coding and
functionality. The generous on-line help by many members of the R
community over more than 20 years is also warmly thanked.
