Download WaPOR Rasters Once for Local or Offline Analysis

Saves one GeoTIFF per time step for an area, in the layout wapor_run_seasonal_analysis() reads with data_source = "local": <folder>/<variable>/<provider>.<variable>.<date>.tif. Files that are already there are not downloaded again, so the call can be repeated to complete or extend a period, and it works without internet once the files exist.

Usage

wapor_download(
  variable,
  region,
  period,
  folder,
  l3_region = NULL,
  mask = FALSE,
  overwrite = FALSE
)

Arguments

variable: Character vector of variable codes (for example c("L3-AETI-D", "L1-RET-D")).
region: Area to download: a vector file path, an sf object, a bounding box c(xmin, ymin, xmax, ymax) in WGS84, or an L3 region code.
period: c(start_date, end_date) in "YYYY-MM-DD" format.
folder: Folder that holds one sub-folder per variable. Created if needed.
l3_region: Optional L3 region code for Level 3 variables.
mask: Logical. FALSE (default) keeps every pixel of the bounding box of region. TRUE sets pixels outside a polygon region to NA; do not use it for coarse Level 1 variables, where one pixel covers many fields.
overwrite: Logical. Download the files of period again and replace them (for the same area). Default FALSE.

Value

Invisibly, the paths of the files for the period: a character vector for one variable, a named list for several. Each vector carries an attribute "wapor_status" with the number of files downloaded, already present, and whether the server was reachable.

Details

Since version 1.0.6 streaming from the server is about as fast as reading local files, so this is for work without a connection (field work, training rooms) and for analyses that are repeated many times on the same area.

Values are stored in the unit of the source (for example mm/day for dekadal evapotranspiration): the scale factor of the WaPOR files is applied exactly once and no temporal conversion is made, which is what the seasonal analysis expects from local files. AgERA5 temperatures are converted to degrees Celsius.

Each file is written under a temporary name and renamed when complete, so an interrupted download never leaves a partial file that a later call would skip.

A folder belongs to one area. The first download writes the area into <folder>/<variable>/.wapor_download.json; a later call for an area that is not inside it (or with a different mask) stops instead of mixing extents, also with overwrite = TRUE. Use another folder for another area.

Without a connection the function returns the files already saved for the period and warns that it could not check whether the period is complete. It stops when there are none.

Examples

if (FALSE) { # \dontrun{
files <- wapor_download(
  variable = c("L3-AETI-D", "L1-RET-D"),
  region   = "citrus_fields.geojson",
  period   = c("2024-03-01", "2025-02-28"),
  folder   = "wapor_data",
  l3_region = "JVA"
)
attr(files[["L3-AETI-D"]], "wapor_status")
} # }