A single-date MODIS worker for parallelization

The function operates at MODIS/VIIRS products on a daily basis. Given that the raw hdf files are downloaded from NASA, standard file names include a data retrieval date flag starting with letter "A". Leveraging that piece of information, the function will select files of scope on the date of interest. Please note that this function does not provide a function to filter swaths or tiles, so it is strongly recommended to check and pre-filter the file names at users' discretion.

Usage

calc_modis_daily(
  from = NULL,
  locs = NULL,
  locs_id = "site_id",
  radius = 0L,
  date = NULL,
  name_extracted = NULL,
  fun_summary = "mean",
  max_cells = 3e+07,
  geom = FALSE,
  ...
)

Arguments

from

SpatRaster. Preprocessed objects.

locs

SpatVector/sf/sftime object. Locations where MODIS values are summarized.

locs_id

character(1). Field name where unique site identifiers are stored. Default is "site_id"

radius

numeric. Radius to generate circular buffers.

date

Date(1). date to query.

name_extracted

character. Names of calculated covariates.

fun_summary

function. Summary function for multilayer rasters. Passed to foo. See exactextractr::exact_extract for details.

max_cells

integer(1). Maximum number of cells to be read at once. Higher values will expedite processing, but will increase memory usage. Maximum possible value is 2^31 - 1.

geom

logical(1). Should the function return a SpatVector? Default is FALSE. The coordinate reference system of the SpatVector is that of from. See exactextractr::exact_extract for details.

...

Placeholders.

Value

a data.frame or SpatVector object.

See also

• Preprocessing: process_modis_merge(), process_modis_swath(), process_blackmarble()

• Parallelization: calc_modis_par()

Author

Insang Song

Examples

## NOTE: Example is wrapped in `\dontrun{}` as function requires a large
##       amount of data which is not included in the package.
if (FALSE) { # \dontrun{
locs <- data.frame(lon = -78.8277, lat = 35.95013, id = "001")
calc_modis_daily(
  from = mod06l2_warp, # dervied from process_modis() example
  locs = locs,
  locs_id = "id",
  radius = 0,
  date = "2024-01-01",
  name_extracted = "cloud_fraction_0",
  fun_summary = "mean",
  max_cells = 3e7
)
} # }