Update documentation to CF-1.13

Author: pvanlaake

DESCRIPTION

@@ -11,7 +11,7 @@ Description: Support for all calendars as specified in the Climate and Forecast
     Climate Change (IPCC). This package specifically allows the user to work 
     with any of the CF-compliant calendars (many of which are not compliant with 
     POSIXt). The CF time coordinate is formally defined in the CF Metadata 
-    Conventions document available at <https://cfconventions.org/Data/cf-conventions/cf-conventions-1.12/cf-conventions.html#time-coordinate>.
+    Conventions document available at <https://cfconventions.org/Data/cf-conventions/cf-conventions-1.13/cf-conventions.html#time-coordinate>.
 License: MIT + file LICENSE
 Encoding: UTF-8
 Roxygen: list(markdown = TRUE)

NEWS.md

@@ -1,3 +1,10 @@
+# CFtime (development version)
+
+Maintenance release
+
+* Support for CF-1.13.
+* Documentation updated.
+
 # CFtime 1.7.2
 
 Maintenance release

R/CFCalendar.R

@@ -24,7 +24,7 @@ NULL
 #'   \item [`360_day`][CFCalendar360], all years have 360 days, divided over 12 months of 30 days.
 #' }
 #' @references
-#'   https://cfconventions.org/Data/cf-conventions/cf-conventions-1.12/cf-conventions.html#calendar
+#'   https://cfconventions.org/Data/cf-conventions/cf-conventions-1.13/cf-conventions.html#calendar
 #' @docType class
 CFCalendar <- R6::R6Class("CFCalendar",
   private = list(

R/CFClimatology.R

@@ -10,7 +10,7 @@
 #'
 #' @export
 #' @references
-#'   https://cfconventions.org/Data/cf-conventions/cf-conventions-1.12/cf-conventions.html#climatological-statistics
+#'   https://cfconventions.org/Data/cf-conventions/cf-conventions-1.13/cf-conventions.html#climatological-statistics
 #' @docType class
 CFClimatology <- R6::R6Class("CFClimatology",
   inherit = CFTime,

R/CFtime-package.R

@@ -8,10 +8,10 @@
 #' Climate Change (IPCC). This package specifically allows the user to work
 #' with any of the CF-compliant calendars (many of which are not compliant with
 #' POSIXt). The CF time coordinate is formally defined in the
-#' [CF Metadata Conventions document](https://cfconventions.org/Data/cf-conventions/cf-conventions-1.12/cf-conventions.html#time-coordinate).
+#' [CF Metadata Conventions document](https://cfconventions.org/Data/cf-conventions/cf-conventions-1.13/cf-conventions.html#time-coordinate).
 #'
 #' This package also supports the creation of a "time" dimension, using class
-#' `CFClimatology`, for climatological statistics as defined [here](https://cfconventions.org/Data/cf-conventions/cf-conventions-1.12/cf-conventions.html#climatological-statistics).
+#' `CFClimatology`, for climatological statistics as defined [here](https://cfconventions.org/Data/cf-conventions/cf-conventions-1.13/cf-conventions.html#climatological-statistics).
 #'
 #' The package can create a [CFTime] or [CFClimatology] instance from scratch or, more commonly, it
 #' can use the dimension attributes and dimension variable values from a netCDF

R/CFtime.R

@@ -16,7 +16,7 @@
 #'
 #' @export
 #' @references
-#'   https://cfconventions.org/Data/cf-conventions/cf-conventions-1.12/cf-conventions.html#time-coordinate
+#'   https://cfconventions.org/Data/cf-conventions/cf-conventions-1.13/cf-conventions.html#time-coordinate
 #' @docType class
 CFTime <- R6::R6Class("CFTime",
   private = list(

README.Rmd

@@ -21,7 +21,7 @@ knitr::opts_chunk$set(
 
 <!-- badges: end -->
 
-CFtime is an R package that supports working with [CF Metadata Conventions](http://cfconventions.org) time coordinates, specifically geared to time-referencing data sets of climate projections such as those produced under the [World Climate Research Programme](https://www.wcrp-climate.org) and re-analysis data such as ERA5 from the European Centre for Medium-range Weather Forecasts (ECMWF).
+CFtime is an R package that supports working with [CF Metadata Conventions](https://cfconventions.org) time coordinates, specifically geared to time-referencing data sets of climate projections such as those produced under the [World Climate Research Programme](https://www.wcrp-climate.org) and re-analysis data such as ERA5 from the European Centre for Medium-range Weather Forecasts (ECMWF).
 
 The data sets include in their metadata an epoch, or origin, a point in time from which other points in time are calculated. This epoch takes the form of `days since 1949-12-01`, with each data collection (Coupled Model Intercomparison Project (CMIP) generation, model, etc) having its own epoch. The data itself has a temporal dimension if a coordinate variable in the netCDF file has an attribute `units` with a string value describing an epoch. The coordinate variable, say "time", has data values such as 43289, which are offsets from the epoch in units of the epoch string ("days" in this case). To convert this offset to a date, using a specific calendar, is what this package does. Given that the calendars supported by the CF Metadata Conventions are not compatible with `POSIXt`, this conversion is not trivial because the standard R date-time operations do not give correct results. That it is important to account for these differences is easily demonstrated:
 
@@ -39,10 +39,10 @@ That's a difference of nearly 21 months! (And yes, 30 February is a valid date o
 
 All defined calendars of the CF Metadata Conventions are supported:
 
--   `standard` or `gregorian`: This calendar is valid for the Common Era only; it starts at 0001-01-01 00:00:00, i.e. 1 January of year 1. Time periods prior to the introduction of the Gregorian calendar (1582-10-15) use the `julian` calendar that was in common use then. The 10-day gap between the Julian and Gregorian calendars is observed, so dates in the range 5 to 14 October 1582 are invalid.
+-   `standard` (or the deprecated `gregorian`): This calendar is valid for the Common Era only; it starts at `0001-01-01T00:00:00`, i.e. 1 January of year 1. Time periods prior to the introduction of the Gregorian calendar (`1582-10-15`) use the `julian` calendar that was in common use then. The 10-day gap between the Julian and Gregorian calendars is observed, so dates in the range 5 to 14 October 1582 are invalid.
 -   `proleptic_gregorian`: This calendar uses the Gregorian calendar for periods prior to the introduction of that calendar as well, and it extends to periods before the Common Era, e.g. year 0 and negative years.
--   `tai`: International Atomic Time, a global standard for linear time based on multiple atomic clocks: it counts seconds since its start at 1958-01-01 00:00:00. For presentation it uses the Gregorian calendar. Timestamps prior to its start are not allowed.
--   `utc`: Coordinated Universal Time, the standard for civil timekeeping all over the world. It is based on International Atomic Time but it uses occasional leap seconds to remain synchronous with Earth's rotation around the Sun; at the end of 2024 it is 37 seconds behind `tai`. It uses the Gregorian calendar with a start at 1972-01-01 00:00:00; earlier timestamps are not allowed. Future timestamps are also not allowed because the insertion of leap seconds is unpredictable. Most computer clocks synchronize against UTC but calculations of periods do not consider leap seconds.
+-   `tai`: International Atomic Time, a global standard for linear time based on multiple atomic clocks: it counts seconds since its start at `1958-01-01T00:00:00`. For presentation it uses the Gregorian calendar. Timestamps prior to its start are not allowed.
+-   `utc`: Coordinated Universal Time, the standard for civil timekeeping all over the world. It is based on International Atomic Time but it uses occasional leap seconds to remain synchronous with Earth's rotation around the Sun; at the end of 2025 it is 37 seconds behind `tai`. It uses the Gregorian calendar with a start at `1972-01-01T00:00:00`; earlier timestamps are not allowed. Future timestamps are also not allowed because the insertion of leap seconds is unpredictable. Most computer clocks synchronize against UTC but calculations of periods do not consider leap seconds (but `CFtime` does).
 -   `julian`: The `julian` calendar has a leap year every four years, including centennial years. Otherwise it is the same as the `standard` calendar.
 -   `365_day` or `noleap`: This is a "model time" calendar in which no leap years occur. Year 0 exists, as well as years prior to that.
 -   `366_day` or `all_leap`: This is a "model time" calendar in which all years are leap years. Year 0 exists, as well as years prior to that.

README.md

@@ -23,7 +23,7 @@ commit](https://img.shields.io/github/last-commit/R-CF/CFtime)](https://github.c
 <!-- badges: end -->
 
 CFtime is an R package that supports working with [CF Metadata
-Conventions](http://cfconventions.org) time coordinates, specifically
+Conventions](https://cfconventions.org) time coordinates, specifically
 geared to time-referencing data sets of climate projections such as
 those produced under the [World Climate Research
 Programme](https://www.wcrp-climate.org) and re-analysis data such as
@@ -62,29 +62,31 @@ valid date on a `360_day` calendar.)
 
 All defined calendars of the CF Metadata Conventions are supported:
 
-- `standard` or `gregorian`: This calendar is valid for the Common Era
-  only; it starts at 0001-01-01 00:00:00, i.e. 1 January of year 1. Time
-  periods prior to the introduction of the Gregorian calendar
-  (1582-10-15) use the `julian` calendar that was in common use then.
-  The 10-day gap between the Julian and Gregorian calendars is observed,
-  so dates in the range 5 to 14 October 1582 are invalid.
+- `standard` (or the deprecated `gregorian`): This calendar is valid for
+  the Common Era only; it starts at `0001-01-01T00:00:00`, i.e. 1
+  January of year 1. Time periods prior to the introduction of the
+  Gregorian calendar (`1582-10-15`) use the `julian` calendar that was
+  in common use then. The 10-day gap between the Julian and Gregorian
+  calendars is observed, so dates in the range 5 to 14 October 1582 are
+  invalid.
 - `proleptic_gregorian`: This calendar uses the Gregorian calendar for
   periods prior to the introduction of that calendar as well, and it
   extends to periods before the Common Era, e.g. year 0 and negative
   years.
 - `tai`: International Atomic Time, a global standard for linear time
   based on multiple atomic clocks: it counts seconds since its start at
-  1958-01-01 00:00:00. For presentation it uses the Gregorian calendar.
-  Timestamps prior to its start are not allowed.
+  `1958-01-01T00:00:00`. For presentation it uses the Gregorian
+  calendar. Timestamps prior to its start are not allowed.
 - `utc`: Coordinated Universal Time, the standard for civil timekeeping
   all over the world. It is based on International Atomic Time but it
   uses occasional leap seconds to remain synchronous with Earth’s
-  rotation around the Sun; at the end of 2024 it is 37 seconds behind
-  `tai`. It uses the Gregorian calendar with a start at 1972-01-01
-  00:00:00; earlier timestamps are not allowed. Future timestamps are
-  also not allowed because the insertion of leap seconds is
-  unpredictable. Most computer clocks synchronize against UTC but
-  calculations of periods do not consider leap seconds.
+  rotation around the Sun; at the end of 2025 it is 37 seconds behind
+  `tai`. It uses the Gregorian calendar with a start at
+  `1972-01-01T00:00:00`; earlier timestamps are not allowed. Future
+  timestamps are also not allowed because the insertion of leap seconds
+  is unpredictable. Most computer clocks synchronize against UTC but
+  calculations of periods do not consider leap seconds (but `CFtime`
+  does).
 - `julian`: The `julian` calendar has a leap year every four years,
   including centennial years. Otherwise it is the same as the `standard`
   calendar.