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Obtain sunrise and sunset times

Source: R/sunRiseSet.R
sunRiseSet.Rd

Create and add sunrise and sunset columns to tag data. Can take a motus database table, but will always return a collected data frame. Requires data containing at least latitude, longitude, and time.

Usage

sunRiseSet(
  df_src,
  lat = "recvDeployLat",
  lon = "recvDeployLon",
  ts = "ts",
  data
)

Arguments

df_src

Data frame, SQLite connection, or SQLite table. An SQLite connection would be the result of tagme(XXX) or DBI::dbConnect(RSQLite::SQLite(), "XXX.motus"); an SQLite table would be the result of dplyr::tbl(tags, "alltags"); a data frame could be the result of dplyr::tbl(tags, "alltags") %>% dplyr::collect().

lat

Character. Name of column with latitude values, defaults to recvDeployLat.

lon

Character. Name of column with longitude values, defaults to recvDeployLon.

ts

Character. Name of column with timestamp values, defaults to ts.

data

Defunct, use src, df_src, or df instead.

Value

Original data (as a flat data frame), with the following additional columns:

  • sunrise - Time of sunrise in UTC for that row's date and location

  • sunset - Time of sunset in UTC for that row's date and location

Details

Note that this will always return the sunrise and sunset of the local date. For example, 2023-01-01 04:00:00 in Central North American time is 2023-01-01 in UTC, but 2023-01-01 20:00:00 is actually the following date in UTC. Because Motus timestamps are UTC, times are first converted to their local time zone time using the lat/lon coordinates before extracting the date. Thus:

  • A UTC timestamp of 1672624800 for Winnipeg, Canada is 2023-01-02 02:00:00 UTC and 2023-01-01 20:00:00 local time

  • Therefore sunRiseSet() calculates the sunrise/sunset times for 2023-01-01 (not for 2023-01-02)

  • These sunrise/sunset times are returned in UTC: 2023-01-01 14:27:50 UTC and 2023-01-01 22:38:30 UTC

  • Note that the UTC timestamp 2023-01-02 02:00:00 is later than the sunset time of 2023-01-01 22:38:30 UTC. This makes sense, as we know that the timestamp is ~8pm local time, well after sunset in the winter for that date.

Examples

# Download sample project 176 to .motus database (username/password are "motus.sample")
if (FALSE) sql_motus <- tagme(176, new = TRUE)

# Or use example data base in memory
sql_motus <- tagmeSample()

# For SQLite Data base-----------------------------------------------
sun <- sunRiseSet(sql_motus)
#> 'df_src' is a complete motus data base, using 'alltags' view

# For specific SQLite table/view ------------------------------------
library(dplyr)
tbl_alltagsGPS <- tbl(sql_motus, "alltagsGPS") 
sun <- sunRiseSet(tbl_alltagsGPS)

# For a flattened data frame ----------------------------------------
df_alltagsGPS <- collect(tbl_alltagsGPS)
sun <- sunRiseSet(df_alltagsGPS)

# Using alternate lat/lons ------------------------------------------
# Get sunrise and sunset information from tbl_alltags using gps lat/lon
# Note this will only work if there are non-NA values in gpsLat/gpsLon
if (FALSE) sun <- sunRiseSet(tbl_alltagsGPS, lat = "gpsLat", lon = "gpsLon")