# Transforms clock time to solar times. Transforms time expressed relative to either the time of a single solar event (anchor times - Nouvellet et al. 2012), or two solar events (such as sun rise and sun set - Vazquez et al. in press). ```r transtime( dat, anchor, mnanchor = NULL, type = c("average", "equinoctial", "single") ) ``` ## Arguments - `dat`: A vector of radian event clock times. - `anchor`: A vector or matrix matched with `dat` containing radian anchor times on the day of each event (see Details). - `mnanchor`: A scalar or two-element vector of numeric radian mean anchor times (see Details). - `type`: The type of transformation to use (see Details). ## Returns A vector of radian transformed times. ## Details If double anchoring is requested (i.e. `type` is equinoctial or average), the `anchor` argument requires a two-column matrix, otherwise a vector. The argument `mnanchor` can usually be left at its default `NULL` value. In this case, the mean anchors are set to `c(pi/2, pi*3/2)` when `type`=="equinoctial", otherwise the `anchor` mean(s). Although the anchors for transformation are usually likely to be solar events (e.g. sun rise and/or sunset), they could be other celestial (e.g. lunar) or human-related (e.g. timing of artificial lighting) events. ## Examples ```r data(BCItime) subdat <- subset(BCItime, species=="ocelot") suntimes <- pi/12 * get_suntimes(subdat$date, 9.156335, -79.847682, -5)[, -3] rawtimes <- subdat$time*2*pi avgtimes <- transtime(rawtimes, suntimes) eqntimes <- transtime(rawtimes, suntimes, type="equinoctial") sngtimes <- transtime(rawtimes, suntimes[,1], type="single") rawAct <- fitact(rawtimes) avgAct <- fitact(avgtimes) eqnAct <- fitact(eqntimes) sngAct <- fitact(sngtimes) plot(rawAct) plot(avgAct, add=TRUE, data="n", tline=list(col="magenta")) plot(eqnAct, add=TRUE, data="n", tline=list(col="orange")) plot(sngAct, add=TRUE, data="n", tline=list(col="cyan")) ``` ## References Vazquez, C., Rowcliffe, J.M., Spoelstra, K. and Jansen, P.A. in press. Comparing diel activity patterns of wildlife across latitudes and seasons: time transformation using day length. Methods in Ecology and Evolution. Nouvellet, P., Rasmussen, G.S.A., Macdonald, D.W. and Courchamp, F. 2012. Noisy clocks and silent sunrises: measurement methods of daily activity pattern. Journal of Zoology 286: 179-184.

transtime function