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suntools

suntools provides functions for calculating the sun’s position,sunrise, sunset, solar noon, and crepuscular (twilight) times for anygiven geographical location and time on earth. Functions in suntoolsused to be part of themaptools package.The functions are based on equations provided by the National Oceanic& Atmospheric Administration (NOAA).

Main package functions: *crepuscule(): Calculatescrepuscular (twilight) times, i.e. the time of dawn or dusk. *sunriset(): Calculates the times of sunrise and sunset at agiven location. *solarpos(): Calculates the solar position(elevation and azimuth) at a given location and time. *solarnoon(): Calculates solar noon time at a givenlocation.

Installation

You can install the released version of suntools fromCRAN with:

install.packages("suntools")

Alternatively, you can install the development version fromGitHub with:

devtools::install_github("adokter/suntools")

Example

library(suntools)#Calculate sunset in Ithaca, NY, USA on June 1, 2023sunriset(matrix(c(-76.4511,42.4800),nrow =1),as.POSIXct("2023-06-01",tz ="America/New_York"),direction='sunset',POSIXct.out=TRUE)#  day_frac                time#1 0.858628 2023-06-01 20:36:25

Author(s)

• Greg Pelletier(gpel461@ecy.wa.gov)- Original VBA code available fromEcologyWA Gov: Models & Tools for TMDLs, who in turn translated it fromoriginal Javascript code by NOAA
• Sebastian P. Luque(spluque@gmail.com),translated from Greg Pelletier’s code
  
• Roger Bivand(roger.bivand@nhh.no)adapted the code to work with sp classes.
• Adriaan M. Dokter(amd427@cornell.edu)adapted the code to work with sf classes.
• Pieter Huijbrechts(pieter.huybrechts@inbo.be)set up continuous integration and automated tests.
• Alexander Tedeschi(at744@cornell.edu)made tests and documentation roxygen compatible

References

This package uses algorithms provided by the National Oceanic &Atmospheric Administration (NOAA), for more information see

• Meeus, J. (1991) Astronomical Algorithms. Willmann-Bell, Inc.
• NOAA’sSunrise/SunsetCalculator
• NOAA’sSolarPosition Calculator
• NOAA’SSolarCalculation Details