Download IGN scanned maps (SCAN25, SCAN100, OACI or IGN maps)

Downloads a scanned map layer from the IGN WMS service for the area covering x, expanded with a buffer. The result is returned as a SpatRaster with a fixed spatial resolution.

Usage

get_scan(
  x,
  type = c("scan25", "scan100", "oaci", "carte_ign"),
  buffer = 1000,
  res = 0.8,
  crs = 2154,
  overwrite = FALSE,
  verbose = TRUE
)

Arguments

x

sf or sfc; Geometry located in France.

type

character; Type of scanned map to download. Must be one of:

• "scan25": SCAN25 topographic map

• "scan100": SCAN100 topographic map

• "oaci": OACI aeronautical chart

• "carte_ign": standard IGN map background

buffer

numeric; Buffer around x (in meters) used to enlarge the download area.

res

numeric; Spatial resolution of the output raster (in map units, usually meters).

crs

numeric or character; CRS of the returned raster.

overwrite

logical; If TRUE, the cached file is overwritten.

verbose

logical; If TRUE, display GDAL messages during download.

Value

A SpatRaster object from the terra package.

Details

Supported layers include SCAN25, SCAN100, OACI aeronautical charts and standard IGN maps.

The scanned map is retrieved for the full bounding box (bbox) of x expanded with the specified buffer.

To improve performance and avoid repeated downloads, the raster is cached in a temporary directory. The cache key depends on the bounding box, resolution and CRS. Set overwrite = TRUE to force a new download.

See also

sf::gdal_utils()

Examples

if (FALSE) { # \dontrun{
p <- sf::st_sfc(
  sf::st_point(c(-4.3727, 47.7982)),
  crs = 4326
)

scan25 <- get_scan(p, type = "scan25", buffer = 500)
scan100 <- get_scan(p, type = "scan100", buffer = 500)

terra::plotRGB(scan25)
} # }