Download camera images to disk — download

Lists available images for a camera and downloads them to a local directory. Images are fetched directly from USGS S3 storage; no API key is required for the downloads themselves.

Usage

download_images(
  cam_id = NULL,
  dest_dir,
  size = "small",
  limit = 1000L,
  time = NULL,
  overwrite = FALSE,
  site_id = NULL
)

Arguments

cam_id: Character. Camera identifier. Use find_cameras() to look up valid IDs. Cannot be used together with site_id.
dest_dir: Character. Path to an existing local directory where images will be saved.
size: Image size passed to build_image_url(). One of "small" (default), "overlay", or "thumb".
limit: Integer between 1 and 50000. Page size for the internal list_images() call. Default is 1000. All images in the requested time range are downloaded via automatic pagination.
time: POSIXct, Date, or character vector of length 1 or 2 used to filter images by capture time. A length-1 value is treated as a start (on or after). A length-2 vector sets the start and end; use NA for an open bound. See list_images() for full details.
overwrite: Logical. If FALSE (default), skip files that already exist in dest_dir (resume behaviour).
site_id: Character. NWIS site number (e.g. "05366800" or "USGS-05366800"). Cannot be used together with cam_id. If the site has more than one camera, supply cam_id directly.

Value

A character vector of local file paths, invisibly. Failed downloads are represented as NA.

Details

Identify the camera with either cam_id or site_id — provide exactly one. site_id accepts both bare NWIS numbers ("05366800") and the USGS- prefixed form ("USGS-05366800"). When a site has multiple cameras, specify the desired camera via cam_id instead.

Examples

if (FALSE) { # \dontrun{
# By cam_id
paths <- download_images(
  "WI_Chippewa_River_at_Grand_Ave_at_Eau_Claire",
  dest_dir = tempdir(),
  limit    = 5
)

# By USGS site ID
paths <- download_images(
  site_id  = "USGS-05366800",
  dest_dir = tempdir(),
  limit    = 5
)
} # }