prism_archive_subset: Subsets PRISM folders on the disk

Description

prism_archive_subset() subsets the PRISM folders stored on disk by type, temporal period, and date. It looks through all of the PRISM data that have been downloaded in the prism archive (prism_get_dl_dir()) and returns the subset based on the specified type, temp_period, and dates.

Usage

prism_archive_subset(
  type,
  temp_period,
  years = NULL,
  mon = NULL,
  minDate = NULL,
  maxDate = NULL,
  dates = NULL,
  resolution = NULL
)

Value

A character vector of the folders that meet the type and temporal period specified. character(0) is returned if no folders are found that meet the specifications.

Arguments

type: The type of data you want to subset. Must be "ppt", "tmean", "tmin", "tmax", "tdmean", "vpdmin", or "vpdmax".
temp_period: The temporal period to subset. Must be "annual", "monthly", "daily", "monthly normals", or "annual normals".
years: Valid numeric year, or vector of years.
mon: Valid numeric month, or vector of months.
minDate: Date to start subsetting daily data. Must be specified in a valid iso-8601 (e.g. YYYY-MM-DD) format. May be provided as either a character or base::Date class.
maxDate: Date to end subsetting daily data. Must be specified in a valid iso-8601 (e.g. YYYY-MM-DD) format. May be provided as either a character or base::Date class.
dates: A vector of daily dates to subset. Must be specified in a valid iso-8601 (e.g. YYYY-MM-DD) format. May be provided as either a character or base::Date class.
resolution: The spatial resolution of the data, must be either "4km" or "800m". Should only be specified for temp_period of "normals".

Details

temp_period must be specified so the function can distinguish between wanting annual data or wanting monthly data for a specified year. For example prism_archive_subset("tmean", "annual", years = 2012) would provide only one folder: the annual average temperature for 2012. However, prism_archive_subset("tmean", "monthly", years = 2012) would provide 12 folders: each monthly tmean folder for 2012.

temp_period, years, and mon can be combined in various different ways to obtain different groupings of data. years, mon, and the daily specifiers (minDate/maxDate or dates) are optional. Not specifying any of those would result in getting all annual, monthly, or daily data.

minDate/maxDate or dates should only be specified for a temp_period of "daily". Additionally, only dates, or minDate and maxDate, should be specified, but all three should not be specified. Nor should the daily arguments be combined with years and/or mon. For example, if daily folders are desired, then specify years and/or mon to get all days for those years and months or specify the specific dates using minDate/maxDate or dates

Examples

Run this code

if (FALSE) {
# get all annual tmin
prism_archive_subset("tmin", "annual")
# get only 2000-2015 annual tmin
prism_subset_folder("tmin", "annual", years = 2000-2015)

# get monthly precipitation for 2000-2010
prism_archive_subset("ppt", "monthly", years = 2000-2010)
# get only June-August monthly precip data for 2000-2010
prism_archive_subset("ppt", "monthly", years = 2000-2010, mon = 6:8)

# get all daily tmax for July-August in 2010
prism_archive_subset("tmax", "daily", years = 2010, mon = 7:8)
# same as:
prism_archive_subset(
  "tmax", 
  "daily", 
  minDate = "2010-07-01", 
  maxDate = "2010-08-31"
)

# get the 4km 30-year average precip for January and February
prism_archive_subset("ppt", "monthly normals", mon = 1:2, resolution = "4km")
}