Description Usage Arguments Value Author(s) References Examples

Converts a vector of clock times to "sun times", by mapping sunrise to *π/2* and sunset to *3π/2*. Sunrise and sunset times are determined based on the dates and locations provided. See Nouvellet et al (2012) for a discussion. Requires the maptools package.

1 |

`clockTime` |
a vector of times of observations in |

`Dates` |
a POSIXct object with the dates of the observations; the time zone must be set to the time zone used for 'clockTime'. |

`Coords` |
a SpatialPoints object with the locations of the observations, or with a single point giving a approximate location for the study area; the coordinates must be geographical coordinates, eg, WGS84, with long before lat. |

Returns a vector of "sun times" in *radians*, where *π/2* corresponds to sunrise and *3π/2* to sunset.

Mike Meredith.

Nouvellet et al (2012) Noisy clocks and silent sunrises: measurement methods of daily activity pattern. *Journal of Zoology* 286:179-184.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 | ```
# Check that sp and maptools packages are installed
if(requireNamespace("sp") && requireNamespace("maptools")) {
# Get example data:
data(simCalls)
str(simCalls)
# Convert dates to a POSIXct object with the right time zone (GMT):
Dates <- as.POSIXct(simCalls$dates, tz="GMT")
# Create a SpatialPoints object with the location
coords <- matrix(c(-3, 56), nrow=1)
Coords <- sp::SpatialPoints(coords, proj4string=sp::CRS("+proj=longlat +datum=WGS84"))
st <- sunTime(simCalls$time, Dates, Coords)
par(mfrow=2:1)
densityPlot(st, col='red', lwd=2, xaxt='n', main="Sun time")
axis(1, at=c(0, 6, 12, 18, 24),
labels=c("midnight", "sunrise", "noon", "sunset", "midnight"))
densityPlot(simCalls$time, lwd=2, main="Clock time")
par(mfrow=c(1,1))
}
``` |

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