R/s2_tiles.R

In pobsteta/theia2r: An R toolbox to find, download and preprocess Sentinel-2 data

#' @title Load Sentinel-2 tiles
#' @description Load the vector object of the Sentinel-2 tiles.
#' @return An sf spatial object containing the extent of the tiles.
#' @export
#' @importFrom sf st_read
#' @importFrom utils unzip
#' @author Luigi Ranghetti, phD (2018) \email{ranghetti.l@@irea.cnr.it}
#' @note License: GPL 3.0
#' @examples 
#' s2tiles <- s2_tiles()
#' 
#' \dontrun{
#' s2tiles_it <- s2tiles[grep('^3[23]T', s2tiles$tile_id),]
#' mapview::mapview(s2tiles_it)}

s2_tiles <- function() {
    
    # extract and import tiles kml
    s2tiles_kmz <- system.file("extdata", "vector", "s2_tiles.kmz", package = "theia2r")
    s2tiles_kml <- gsub("\\.kmz$", ".kml", s2tiles_kmz)
    if (!file.exists(s2tiles_kml)) {
        unzip(zipfile = s2tiles_kmz, files = basename(s2tiles_kml), exdir = dirname(s2tiles_kml), unzip = "internal")
    }
    s2tiles <- st_read(s2tiles_kml, stringsAsFactors = FALSE, quiet = TRUE)
    s2tiles[, !names(s2tiles) %in% c("Name", "geometry")] <- NULL
    names(s2tiles) <- gsub("^Name$", "tile_id", names(s2tiles))
    s2tiles
    
}