daybreak

Compute Sun Rise/Set Times, Start/End of Twilight, and the Length of the Day at Any Date and Latitude

Description

A wrapper for Paul Schlyter’s C-based library for computing sunrise, sunset, twilight start and end, plus the length of day for a given data and coordinates.

What’s Inside The Tin

The following functions are implemented:

astronomical_twilight: Astronomical twilight
civil_twilight: Civil twilight
day_astronomical_twilight_length: Length of astronomical twilight
day_civil_twilight_length: Length of civil twilight
day_length: Length of day
day_nautical_twilight_length: Length of nautical twilight
nautical_twilight: Nautical twilight
sun_rise_set: Sun rise/set times

Installation

install.packages("daybreak", repos = "https://cinc.rud.is")
# or
remotes::install_git("https://git.rud.is/hrbrmstr/daybreak.git")
# or
remotes::install_git("https://git.sr.ht/~hrbrmstr/daybreak")
# or
remotes::install_gitlab("hrbrmstr/daybreak")
# or
remotes::install_bitbucket("hrbrmstr/daybreak")
# or
remotes::install_github("hrbrmstr/daybreak")

NOTE: To use the ‘remotes’ install options you will need to have the {remotes} package installed.

Usage

library(daybreak)

# current version
packageVersion("daybreak")
## [1] '0.1.0'

Near me:

day_length("2019-12-31", -70.8636, 43.2683)
## [1] 9.031444
day_civil_twilight_length("2019-12-31", -70.8636, 43.2683)
## [1] 10.10834
day_nautical_twilight_length("2019-12-31", -70.8636, 43.2683)
## [1] 11.30569
day_astronomical_twilight_length("2019-12-31", -70.8636, 43.2683)
## [1] 12.45998
sun_rise_set("2019-12-31", lon = -70.8636, lat = 43.2683)
## $rise
## [1] 12.25761
## 
## $set
## [1] 21.28906
civil_twilight("2019-12-31", -70.8636, 43.2683)
## $start
## [1] 11.71917
## 
## $end
## [1] 21.82751
nautical_twilight("2019-12-31", -70.8636, 43.2683)
## $start
## [1] 11.12049
## 
## $end
## [1] 22.42618
astronomical_twilight("2019-12-31", -70.8636, 43.2683)
## $start
## [1] 10.54335
## 
## $end
## [1] 23.00332

Tromsø, Norway (Winter)

day_length("2019-12-31", 18.9553, 69.6492)
## [1] 0
day_civil_twilight_length("2019-12-31", 18.9553, 69.6492)
## [1] 4.613116
day_nautical_twilight_length("2019-12-31", 18.9553, 69.6492)
## [1] 8.000323
day_astronomical_twilight_length("2019-12-31", 18.9553, 69.6492)
## [1] 10.5871
sun_rise_set("2019-12-31", 18.9553, 69.6492)
## $rise
## [1] NA
## 
## $set
## [1] NA
civil_twilight("2019-12-31", 18.9553, 69.6492)
## $start
## [1] 8.476866
## 
## $end
## [1] 13.08998
nautical_twilight("2019-12-31", 18.9553, 69.6492)
## $start
## [1] 6.783262
## 
## $end
## [1] 14.78359
astronomical_twilight("2019-12-31", 18.9553, 69.6492)
## $start
## [1] 5.489872
## 
## $end
## [1] 16.07698

Tromsø, Norway (Summer)

day_length("2019-06-01", 18.9553, 69.6492)
## [1] 24
day_civil_twilight_length("2019-06-01", 18.9553, 69.6492)
## [1] 24
day_nautical_twilight_length("2019-06-01", 18.9553, 69.6492)
## [1] 24
day_astronomical_twilight_length("2019-06-01", 18.9553, 69.6492)
## [1] 24
sun_rise_set("2019-06-01", 18.9553, 69.6492)
## $rise
## [1] NA
## 
## $set
## [1] NA
civil_twilight("2019-06-01", 18.9553, 69.6492)
## $start
## [1] NA
## 
## $end
## [1] NA
nautical_twilight("2019-06-01", 18.9553, 69.6492)
## $start
## [1] NA
## 
## $end
## [1] NA
astronomical_twilight("2019-06-01", 18.9553, 69.6492)
## $start
## [1] NA
## 
## $end
## [1] NA

daybreak Metrics

Lang	# Files	(%)	LoC	(%)	Blank lines	(%)	# Lines	(%)
C	3	0.33	267	0.66	110	0.60	245	0.60
R	4	0.44	65	0.16	16	0.09	84	0.20
C/C++ Header	1	0.11	39	0.10	35	0.19	44	0.11
Rmd	1	0.11	32	0.08	21	0.12	37	0.09

Code of Conduct

Please note that this project is released with a Contributor Code of Conduct. By participating in this project you agree to abide by its terms.

Enhancement idea: Adjust sun rise/set hours to match timezone and return `POSIXlt` object

Thanks for the package! I had two ideas that could be a helpful enhancement for sun_rise_set() along with astronomical_twilight, civil_twilight, and nautical_twilight.

The first idea is to match the hours returned to the time zone of the date provided (if the date provided includes a time zone).
The second idea is to optionally return a "POSIXlt" object using the same date as the one provided but the time adjusted to match the sunrise and sunset times (or twilight start and end times).

If you're interested, I put together a helper function that gets this working although I'm open to trying other approaches if you have any suggestions.

sun_rise_set <- function(date, lon, lat, return = "hours", adj_tz = TRUE) {
  date <- valid_date(date)
  lon <- valid_lon(lon)
  lat <- valid_lat(lat)
  times <- .Call("r_sun_rise_set", date$year+1900L, date$mon+1L, date$mday, lon, lat)
  
  if (adj_tz) {
    times$rise <- adjust_tz(date, times$rise, return)
    times$set <- adjust_tz(date, times$set, return)
  }
  times
}

adjust_tz <- function(date, x, return) {
  if ("POSIXt" %in% class(date)) {
    x <- x - as.double(difftime(date, as.POSIXct(date, tz = "UTC"), units = "hours"))
  }
  
  if (return == "hours") {
    x
  } else if (return == "POSIXlt") {
    day <- strftime(date, format="%Y-%m-%d")
    tz <- strftime(date, format="%Z")
    hr <- floor(x)
    min <- (x %% 1) * 60
    sec <- floor((min %% 1) * 60)
    min <- floor(min)
    as.POSIXlt(paste(day, paste0(c(hr, min, sec), collapse = ":"), tz), format = "%Y-%m-%d %H:%M:%S")
  }
}

hrbrmstr / daybreak Goto Github PK

daybreak's Introduction

daybreak

Description

What’s Inside The Tin

Installation

Usage

daybreak Metrics

Code of Conduct

daybreak's People

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daybreak's Issues

Enhancement idea: Adjust sun rise/set hours to match timezone and return `POSIXlt` object

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