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Select time steps from a wind_series

subset_series.Rd

Selects time steps from a wind_series by month, hour of day, date range, or index, keeping the u and v layers of each step together. Use it to build wind roses for the times that matter for dispersal, such as a flowering season or the hours when propagules are released.

Usage

subset_series(
  x,
  months = NULL,
  hours = NULL,
  start = NULL,
  end = NULL,
  steps = NULL
)

Arguments

x

A wind_series, with times in its layer names (see wind_times()) if selecting by months, hours, start, or end.

months

Integer vector of months (1-12) to keep.

hours

Integer vector of hours of the day (0-23, UTC) to keep.

start, end

Keep time steps from start to end, inclusive. Each can be a Date, a POSIXct time, or a character string like "2000-06-01" or "2000-06-01 12:00:00" (interpreted as UTC). A date without a time includes that whole day, so end = "2000-06-30" keeps all of June 30.

steps

Time steps to keep, as integer indices or a logical vector with one element per time step, for selections the other arguments don't cover. Can be combined with them, e.g. steps = speed > 10, given a vector speed.

Value

A wind_series containing the selected time steps, in their original order.

Details

Criteria are combined: a time step is kept only if it meets all of them. Times are in UTC. For hours of the day in local solar time, note that local time is about UTC plus longitude / 15 hours (e.g. UTC - 7 hours at 105 degrees west), so hours for a large region selects different local times in different places.

See also

wind_times()

Examples

series <- windscape_example("wind_series")

# summer only
summer <- subset_series(series, months = 6:8)
range(wind_times(summer))
#> [1] "2000-06-01 00:00:00 UTC" "2000-08-15 18:00:00 UTC"

# afternoons in the first half of the year
subset_series(series, hours = 18:23, end = "2000-06-30")
#> class       : SpatRaster
#> size        : 64, 96, 24  (nrow, ncol, nlyr)
#> resolution  : 0.3157895, 0.3174603  (x, y)
#> extent      : -120.1579, -89.84211, 29.84127, 50.15873  (xmin, xmax, ymin, ymax)
#> coord. ref. : lon/lat WGS 84 (EPSG:4326)
#> sources     : wind_usa.tif
#> names       : u 200~00:00, u 200~00:00, u 200~00:00, u 200~00:00, u 200~00:00, u 200~00:00, ...
#> min values  :        -0.6,        -0.4,        -0.6,        -0.5,        -0.5,        -0.7, ...
#> max values  :           1,         0.8,         1.1,         1.4,         0.7,         0.8, ...