In chepec/photoec: Solar spectra and constants for photoelectrochemistry

title: "How to update the datasets" author: "Taha Ahmed" date: "r Sys.Date()" output: rmarkdown::html_vignette vignette: > %\VignetteIndexEntry{How to update the datasets} %\VignetteEngine{knitr::rmarkdown} %\VignetteEncoding{UTF-8}

This vignette demonstrates how the solarconstants datasets is created. It also shows how the ASTMG173 dataset is ingested (from CSV), so if you for some reason want to edit that dataset, just edit the CSV and re-run this vignette.

library(dplyr)
library(knitr)
library(usethis)   # use_data()
library(tibble)    # tribble()
library(constants) # syms
library(here)      # here()

options(
   digits   = 7,
   width    = 84,
   continue = " ",
   prompt   = "> ",
   warn = 0,
   stringsAsFactors = FALSE)
opts_chunk$set(
   echo       = TRUE,
   eval       = TRUE,
   cache      = TRUE,
   collapse   = TRUE,
   results    = 'hide',
   message    = FALSE,
   warning    = FALSE,
   tidy       = FALSE)

This is the solarconstants dataset:

solarconstants <- tribble(
   ~name,                       ~label,     ~value,       ~reference,        ~label.html,                ~label.tex,                      ~unit.html,  ~unit.tex,
   "Speed of light",            "c",        syms$c0,      "per definition",  "<i>c</i>",                 "\\ensuremath{c}",               "m s⁻¹",     "\\si{\\metre\\per\\second}",
   "Elementary charge",         "e",        syms$e,       "CODATA 2018",     "<i>e</i>",                 "\\ensuremath{e}",               "C",         "\\si{\\coulomb}",
   "Planck's constant",         "h",        syms$h,       "CODATA 2018",     "<i>h</i>",                 "\\ensuremath{h}",               "J s⁻¹",     "\\si{\\joule\\second}",
   "Planck's constant",         "h.eV",     syms$hev,     "CODATA 2018",     "<i>h</i>",                 "\\ensuremath{h}",               "eV s⁻¹",    "\\si{\\electronvolt\\second}",
   "Boltzmann's constant",      "k",        syms$k,       "CODATA 2018",     "<i>k</i>",                 "\\ensuremath{k}",               "J K⁻¹",     "\\si{\\joule\\per\\kelvin}",
   "Stefan-Boltzmann constant", "sigma",    syms$sigma0,  "CODATA 2018",     "σ",                        "\\ensuremath{\\sigma}",         "W m⁻² K⁻⁴", "\\si{\\watt\\per\\square\\metre\\per\\kelvin\\tothe{4}}",
   "Temperature of the Sun",    "T.Sun",    5772,         "NASA, Wikipedia", "<i>T</i><sub>Sun</sub>",   "\\ensuremath{T_\\text{Sun}}",   "K",         "\\si{\\kelvin}",
   "Astronomical unit",         "R.AU",     149597870700, "per definition",  "<i>R</i><sub>AU</sub>",    "\\ensuremath{R_\\text{AU}}",    "m",         "\\si{\\metre}",
   "Radius of the Sun",         "R.Sun",    695700000,    "Wikipedia",       "<i>R</i><sub>Sun</sub>",   "\\ensuremath{R_\\text{Sun}}",   "m",         "\\si{\\metre}",
   "Surface area of the Sun",   "A.Sun",    NA,           "A=4×π×R²",        "<i>A</i><sub>Sun</sub>",   "\\ensuremath{A_\\text{Sun}}",   "m²",        "\\si{\\square\\metre}",
   "Radius of the Earth",       "R.Earth",  6371008.7714, "IUGG, Wikipedia", "<i>R</i><sub>Earth</sub>", "\\ensuremath{R_\\text{Earth}}", "m",         "\\si{\\metre}",
   "Surface area of the Earth", "A.Earth",  NA,           "A=4×π×R²",        "<i>A</i><sub>Earth</sub>", "\\ensuremath{A_\\text{Earth}}", "m²",        "\\si{\\square\\metre}")
solarconstants <-
   solarconstants %>%
   # surface area of the Sun
   mutate(value =
      replace(
         value,
         label == "A.Sun",
         4 * pi * filter(solarconstants, label == "R.Sun")$value^2)) %>%
   # surface area of the Earth
   mutate(value =
      replace(
         value,
         label == "A.Earth",
         4 * pi * filter(solarconstants, label == "R.Earth")$value^2))

Don't forget to update metadata in data.R if you edit the solarconstants dataframe.

ASTM G173, defined by ASTM, published by NREL. See links below. For the Earth radius we are using the globally-average radius as defined by the International Union of Geodesy and Geophysics (IUGG, see Wikipedia link below).

# the CSV file we downloaded from NREL is saved in inst/extdata (it's not modified by this script)
ASTMG173 <- read.csv(
   file = here::here("inst/extdata", "ASTMG173.csv"),
   skip = 1,
   col.names = c(
      "wavelength",          # nm
      "extraterrestrial",    # W m⁻² nm⁻¹
      "globaltilt",          # W m⁻² nm⁻¹
      "direct.circumsolar")) # W m⁻² nm⁻¹

# use_data() saves each object as rda file in ./data/
usethis::use_data(solarconstants, ASTMG173, overwrite = TRUE)
# also save the dataset as csv files, for ease of reading
write.csv(solarconstants, file = here::here("data", "solarconstants.csv"), row.names = FALSE)
write.csv(ASTMG173, file = here::here("data", "ASTMG173.csv"), row.names = FALSE)