modDownload: Download MODIS images from a search list
In RGISTools: Handling Multiplatform Satellite Images

Description Usage Arguments Details Value Examples

modDownload downloads the images from a list of uniform resource locators (URLs) generated by the modSearch function from NASA’s ‘EartData’ plataform. The images are saved as GTiff files in the AppRoot directory.

modDownload(
  searchres,
  AppRoot,
  username = NULL,
  password = NULL,
  nattempts = 5,
  verbose = FALSE,
  extract.tif = FALSE,
  overwrite = FALSE,
  raw.rm = FALSE,
  ...
)

`searchres`	the output from the `modSearch` function.
`AppRoot`	the directory where the images will be saved.
`username`	NASA’s ‘EarthData’ username.
`password`	NASA’s ‘EarthData’ password.
`nattempts`	the number of attempts to download an image in case it becomes corrupted.
`verbose`	logical argument. If `TRUE`, the function prints running stages and warnings.
`extract.tif`	logical argument. If `TRUE`, extracts all the layers from hdf files and saves them as GTiff.
`overwrite`	logical argument. If `TRUE`, overwrites the existing images with the same name.
`raw.rm`	logical argument. If `TRUE`, removes the raw images.
`...`	argument for nested functions: `dates` a vector with the capturing dates being considered for downloading. `bFilter` a vector with the bands to be extracted when `extract.tif=TRUE`. If not supplied, all bands are extracted.

modDownload is able to download MODIS Terra and Aqua products. These products are published in the ‘EarthData’ Platform. The platform is supported by the Earth Observing System Data and Information System (EODIS) and managed NASA’s Earth Science Data Systems (ESDS). modDownload requires credentianls from an ‘EarthData’ account to access the NASA’s web data service, which can be obtained here.

When extract.tif = 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” and the two-digit band number (e.g., “B01”). Image decompression duplicates the information due to the presence of both, compressed and decompressed images. Set raw.rm = TRUE to remove former ones.

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

## Not run: 
# load a spatial polygon object of Navarre
data(ex.navarre)
sres <- modSearch(product = "MYD13A2",
                  startDate = as.Date("01-01-2011", "%d-%m-%Y"),
                  endDate = as.Date("31-12-2013", "%d-%m-%Y"),
                  collection = 6,
                  extent = ex.navarre)
head(sres)
# download the first image in sres
wdir <- file.path(tempdir(),"Path_for_downloading_folder")
print(wdir)
wdir.mod <- file.path(wdir,"Modis","MYD13A2")
wdir.mod.hdf <- file.path(wdir.mod,"hdf")
modDownload(mList[1], 
            username = "username", 
            password = "password",
            AppRoot = wdir.mod.hdf)
# download all images in mList
modDownload(sres, 
            username = "username", 
            password = "password",
            AppRoot = wdir.mod.hdf)

## End(Not run)