Handle Sentinel Imagery in Original Copernicus SAFE Format

Use this function to prepares vegetation index and SWIR Transformed Reflectance (STR) rasters when you have already downloaded Sentinel 2 image files in advance. Unzip the downloaded Sentinel 2 files and do not change the folder structure. This function assumes that atmospheric correction has been applied. i.e. by downloading Level L2A product or using the SNAP L2A_Process,

Usage

optram_safe(
  safe_dir,
  aoi,
  S2_output_dir = tempdir(),
  overwrite = TRUE,
  data_output_dir = tempdir()
)

Arguments

safe_dir,

string, full path to containing folder of downloaded (unzipped) Sentinel 2 data in original SAFE format, after atmospheric correction (L2A)

aoi,

sf object, a POLYGON or MULTIPOLYGON of the AOI boundary

S2_output_dir,

string, directory to save the derived products, defaults to tempdir()

overwrite,

boolean, overwrite derived products that already were created, defaults to TRUE

data_output_dir,

string, path to save coeffs_file and STR-VI data.frame, default is tempdir()

Value

rmse_df, data.frame, RMSE values of fitted trapezoid lines

Note

Use the max_tbl_size parameter to limit the total number of rows in the VI-STR data.frame. When the area of interest is large, or the time range of datasets is long, the total size of the data.frame can grow beyond the capacity of computation resources. This parameter limits the size of the table by sampling a number of data points from each time slot. The sample size is determined based on max_tbl_size and the total number of time slots in the full time range.

Two SWIR bands are available in Sentinel-2: 1610 nanometer (nm) and 2190 nm. Set which band to use with optram_options.

Examples

if (FALSE) {
aoi <- sf::st_read(system.file("extdata",
                  "lachish.gpkg", package = "rOPTRAM"))
safe_dir  <- "...enter directory containing downloaded SAFE folders..."
rmse <- optram_safe(safe_dir, aoi_file)
}