RGISTools (version 0.9.7)

modCloudMask: Create cloud masks for MODIS images

Description

modCloudMask creates cloud masks derived from the "MOD35_L2" product.

Usage

modCloudMask(startDate, endDate, AppRoot, extent, out.name = "outname",
  raw.rm = FALSE, overwrite = FALSE, verbose = FALSE, ...)

Arguments

startDate

a Date class object with the starting date of the study period.

endDate

a Date class object with the ending date of the study period.

AppRoot

the directory where cloud masks are saved.

extent

An extent, Raster*, or Spatial* object representing the region of interest with longitude/latitude coordinates.

out.name

he name of the folder that stores the outputs. By default, <U+201C>outfile<U+201D> is assigned.

raw.rm

logical argument. If TRUE, raw images are removed.

overwrite

logical argument. If TRUE, overwrites the existing images with the same name.

verbose

logical argument. If TRUE, the function prints the running steps and warnings.

...

arguments for nested functions.

Details

This function, downloads and processes the "MOD35_L2" products to create cloud masks composed of NA's (cloud) and 1's (clear). The resulting cloud mask layers need to be reprojected because resolution and projection differences with other MODIS products. This function requires `GDAL' and the `gdalUtils' library properly installed.

Examples

# NOT RUN {
# load a spatial polygon object of Navarre
data(ex.navarre)
src <- paste0(tempdir(),"/Path_for_downloading_folder")
print(src)

# search and download images from MODIS between
# 01-01-2018 and 03-01-2018 for the region of Navarre
modDownload(product = "MOD09GA",
            startDate = as.Date("01-01-2018", "%d-%m-%Y"),
            endDate = as.Date("03-01-2018", "%d-%m-%Y"),
            username = "username",
            password = "password",
            AppRoot = src,
            extract.tif = TRUE,
            collection = 6,
            extent = ex.navarre)
            
# assign src1 as the output folder for modMosaic
src.mod <- file.path(src, "Modis")
src.tiles <- file.path(src.mod, "MOD09GA")
tif.src.tiles <- file.path(src.tiles, "tif")
# mosaic the MODIS images
modMosaic(tif.src.tiles, # the input folder 
          AppRoot = src.tiles, # the output folder 
          out.name = "Navarre", # creates Navarre folder in AppRoot
          gutils = TRUE,
          extent = ex.navarre)
          
# generate the cloud masks      
modCloudMask(startDate = as.Date("01-01-2018", "%d-%m-%Y"),
             endDate = as.Date("04-01-2018", "%d-%m-%Y"),
             extent = ex.navarre,
             AppRoot = src,
             out.name = "Navarre")
             
src.cloud <- file.path(src.mod,"CloudMask")
# the cloud mask may have different extent, resolution...  
src.cloud.navarre <- file.path(src.cloud,"Navarre")
cmask <- list.files(src.cloud.navarre, full.names = TRUE, pattern = "\\.tif$")
cmask.ras <- lapply(cmask, raster)

navarre.path <- file.path(src.tiles, "Navarre")
navarre.img <- list.files(navarre.path,
                          full.names = TRUE,
                          recursive = TRUE,
                          pattern = "\\.tif$")
# select b01
navarre.img <- navarre.img[grepl("b01_1",navarre.img)]
navarre.b01.ras <- lapply(navarre.img,raster)
navarre.b01.stack <- stack(lapply(navarre.b01.ras, projectRaster, navarre.b01.ras[[1]]))

# reproject the cloud mask to the projection of navarre.b01.stack
cmask.stack <- stack(lapply(cmask.ras, projectRaster, navarre.b01.stack))

# plot the cloud free b01 layer
spplot(navarre.b01.stack*cmask.stack)
# }