Download British Columbia Digital Elevation Model data

Download BC DEM data in gridded Canadian Digital Elevation Data (CDED) format.

WARNING: this function is still unstable, and will cause your R Session to abort if you download a large number of tiles. But do not despair! If you download many tiles and your R Session aborts while attempting to stitch your rasters together, the downloaded and unzipped .dem files are somewhere on your machine - R just ran out of memory when actually trying to stitch them together. If you open a new R Session and enter tempdir() into the console, your raster data is somewhere in that vicinity, in one of the Rtmp*/DEM_ZIP/DEM directories on your computer. No need go through the time consuming step of re-downloading all your rasters.

Usage

BC_DEM(
  letterblock,
  save_output = TRUE,
  overwrite = FALSE,
  output_dir = NA,
  filename = NA
)

Arguments

letterblock: Map tiles of DEM data to download, e.g. '92b'. See the BC Maps & Orthos Base Map Online Store here for a visual: https://a100.gov.bc.ca/ext/mtec/public/products/mapsheet
save_output: Logical (T/F). Should the downloaded DEM be saved to your local disk? Default TRUE.
overwrite: Logical (T/F). Should the downloaded DEM overwrite any existing BC DEM data on the disk, if already present? Default FALSE.
output_dir: Output directory to save downloaded DEM to. Defaults to current working directory.
filename: Filename of saved DEM. By default, the filename is either 1) the letterblock names, seperated by underscores (e.g., "92b_92g.dem"), if there are fewer than 5 letterblocks were downloaded; or 2) simply "BC_DEM.dem", if greater than 5 letterblocks were downloaded.

Value

A RasterSpat object.

Examples

if (FALSE) {
BC_DEM("92b", save_output = F) # download Victoria area DEM, don't save it
BC_DEM("103f", output_dir = "temp/bc_dem", filename = "haida_gwaii.dem") # download one tile of Haida Gwaii DEM and save output to "temp/bc_dem/haida_gwaii.dem"
}