add date conversion

NAMESPACE

@@ -5,6 +5,7 @@ export(bioclim_vars)
 export(clean_data_path)
 export(climate_for_locations)
 export(climate_for_time_slice)
+export(date2ybp)
 export(df_from_region_series)
 export(df_from_region_slice)
 export(distance_from_sea)
@@ -36,6 +37,7 @@ export(time_series_for_locations)
 export(update_dataset_list)
 export(validate_nc)
 export(var_labels)
+export(ybp2date)
 exportMethods("time_bp<-")
 exportMethods(bioclim_vars)
 exportMethods(time_bp)

R/download_etopo.R

@@ -27,7 +27,7 @@ download_etopo <- function(path = NULL, resolution = 60) {
   } else if (resolution == 60) {
     etopo_url <- "https://www.ngdc.noaa.gov/thredds/fileServer/global/ETOPO2022/60s/60s_bed_elev_netcdf/ETOPO_2022_v1_60s_N90W180_bed.nc"
   } else {
-    stop("resolution should be one of 30 or 60 arcsecs")
+    stop("resolution should be one of 30 or 60 arc-secs")
   }
 
   # download the files

R/ybp2date.R

@@ -0,0 +1,32 @@
+#' Convert years BP from pastclim to lubridate date, or vice versa
+#'
+#' These functions convert between years BP as used by pastclim (negative
+#' numbers going into
+#' the past, positive into the future) and standard
+#' `POSIXct` date objects.
+#' @param x a time in years BP using the `pastclim` convention of
+#'  negative numbers indicating years into the past, or a `POSIXct` date object
+#' @returns a `POSIXct` date object, or a vector
+#' @examples
+#' ybp2date(-10000)
+#' ybp2date(0)
+#' # back and forth
+#' date2ybp(ybp2date(-10000))
+#'
+#' @export
+
+ybp2date <- function(x) {
+  if (!is.numeric(x)) {
+    stop("x should be numeric")
+  }
+  lubridate::date_decimal(x + 1950)
+}
+
+#' @rdname ybp2date
+#' @export
+date2ybp <- function(x) {
+  if (!inherits(x, "POSIXct")) {
+    stop("x should be a POSIXct object")
+  }
+  lubridate::year(x) - 1950
+}

inst/WORDLIST

@@ -78,6 +78,7 @@ kyr
 lai
 landmask
 longname
+lubridate
 mis
 nc
 netcdf