senDownload: Download Sentinel images from a search list

In spatialstatisticsupna/RGISTools: Handling Multiplatform Satellite Images

Download Sentinel images from a search list

Description

senDownload downloads the images from a list of uniform resource locators (URLs) generated by the senSearch function from ESA’s ‘SciHub’ web service. The images are saved as GTiff files in the AppRoot directory.

Usage

senDownload(
  searchres,
  AppRoot,
  username = NULL,
  password = NULL,
  nattempts = 5,
  unzip = FALSE,
  overwrite = FALSE,
  omit.md5.error = TRUE,
  ...
)

Arguments

searchres	the output from the senSearch function.
AppRoot	the directory where the outcoming time series are saved.
username	ESA’s ‘SciHub’ username.
password	ESA’s ‘SciHub’ password.
nattempts	the number of attempts to download an image in case it becomes corrupted.
unzip	logical argument. If TRUE, unzips the images.
overwrite	logical argument. If TRUE, overwrites the existing images with the same name.
omit.md5.error	logical argument. If TRUE, omits md5 errors and do not removes the downloaded image.
...	arguments for nested functions. dates a vector with the capturing dates being considered for downloading. bFilter a vector with the bands to be extracted when unzip=TRUE. If not supplied, all bands are extracted.

Details

senDownload downloads the list of URLs provided by senSearch. In case the process is interrupted, the image file could be corrupted. The function detects the corrupted files and restarts the process. To prevent the computer from crashing, there is a maximum number of attempts to try to donwnload the image (nattempts). The default number of attempts is set to 3. The function requires an ESA’s ‘SciHub’ account, which can be obtained here.

When unzip = TRUE, the function decompresses the imagery. If only a subset of bands is required, band names can be provided through the bFilter argument. The band names are specified by “B”, followed by the two-digit band number, and the resolution of the band (either 10m, 20m, or 60m) (e.g, "B01_10m"). Image decompression duplicates the information due to the presence of both, compressed and decompressed images. Set raw.rm = TRUE to remove former ones.

Value

this function does not return anything. It saves the imagery as 'zip’ (and JP2 files) in a folder called 'raw’ ('unzip’) in the AppRoot directory.

Examples

## Not run: 
# load a spatial polygon object of Navarre
data(ex.navarre)
# download S2MSI1C products sensed by Sentinel-2
# in July-August 2018
sres <- senSearch(startDate = as.Date("2018-07-29","%Y-%m-%d"),
                       endDate = as.Date("2018-08-06","%Y-%m-%d"),
                       platform = "Sentinel-2",
                       extent = ex.navarre,
                       product = "S2MSI1C",
                       username = "username",
                       password = "password")

# filtering the path R094 where Navarre is located
names(sres)
sres.sen.R094 <- sres[grepl("R094", names(sres))]
names(sres.sen.R094)
# list the dates in sres
senGetDates(names(sres.sen.R094),format="%Y%j")
wdir <- file.path(tempdir(),"Path_for_downloading_folder")
# donwload the imagery
senDownload(searchres = sres,
            username = "username",
            password = "password",
            AppRoot = wdir,
            unzip = TRUE)
wdir.sen.unzip <- file.path(wdir,"Sentinel","unzip")
files.sen.unzip<-list.files(wdir.sen.unzip,
                            pattern = "\\TCI.jp2$",
                            full.names = TRUE,
                            recursive = TRUE)
img.sen.rgb<-stack(files.sen.unzip[1])
plotRGB(img.sen.rgb)

## End(Not run)

spatialstatisticsupna/RGISTools documentation built on Feb. 21, 2023, 12:01 a.m.