03_download_modis_data_spatial.R

# Download all remote sensing data using
# appeears, takes about 8h to complete

library(appeears)
library(dplyr)
library(rnaturalearth)

# grab country polygons from world map
# restrict to selected country
country <- ne_countries(
  scale = 110,
  returnclass = "sf"
  ) |>
  dplyr::filter(
    sovereignt %in%  c("Switzerland","Germany","Austria")
  ) |>
  sf::st_union() |>
  sf::st_as_sf()

# list products to download
product_subset <- c(
  "MOD09GA.061",
  "MOD11A1.061",
  "MYD11A1.061",
  "MCD43A4.061"
  )

# list appeears meta-data and subset
# only the above products
products <- appeears::rs_products() |>
  filter(
    ProductAndVersion %in% product_subset
  )

# loop over all products and create
# basic query data
full_queries <- lapply(
  products$ProductAndVersion,
  function(product){

  # specify the products / bands required
  # grab all non-QA bands
  bands <- rs_layers(product) |>
    filter(
      IsQA == FALSE
    )

  if(product != "MOD11A1.061" ) {
    bands <- bands |>
      filter(
        grepl("refl", Layer, ignore.case = TRUE)
      )
  } else {
    bands <- bands |>
      filter(
        grepl("LST_Day", Layer)
      )
  }

  bands <- bands |>
    select(
      Layer
    )

  base_query <- bands |>
    rowwise() |>
    do({
      data.frame(
        subtask = product,
        task = "spatial",
        start = "2018-05-01",
        end = "2018-11-01",
        product = product,
        layer = as.character(.$Layer)
      )
    })
})

tasks <- full_queries |>
  bind_rows() |>
  group_by(task, subtask) |>
  group_split()

tasks <- lapply(
  tasks, function(task){
    appeears::rs_build_task(
      task,
      roi = country
    )
})

# request the task to be executed
# don't download, just return
# the task ID / request calls
requests <- rs_request_batch(
    request = tasks,
    user = "khufkens",
    workers = 10,
    path = "data-raw/modis_data_spatial/"
  )

# clean up the files which are not required
# first list all files, then select the
# ones to remove (kick those out)
downloaded_files <- list.files(
  "data-raw/modis_data_spatial/",
  "*",
  full.names = TRUE,
  recursive = TRUE
  )

# files_to_remove <- downloaded_files[!grepl("results", downloaded_files)]
#
# # remove files
# file.remove(files_to_remove)