Discover BlueTopo tiles intersecting an AOI — bluertopo

Returns selected NOAA BlueTopo tile footprints and standardized metadata without downloading raster assets.

Usage

bluertopo_tiles(
  aoi,
  resolution = "native",
  coverage = "warn",
  min_coverage = 1,
  cache_dir = bluertopo_cache_dir(),
  refresh = "if_stale",
  quiet = FALSE
)

Arguments

aoi: A polygonal area of interest in one of the formats listed in AOI inputs below.
resolution: A native source-tile selection policy. Supply a shortcut such as "native", "finest", "coarsest", "best_available", "coarsest_available", or "dominant"; a positive numeric meter value for an exact match; or a bluertopo_resolution() object.
coverage: A character scalar controlling incomplete selected coverage: "ignore", "warn", "error", or "fill". "fill" adds fallback native resolutions in policy order until the target is met when possible.
min_coverage: A numeric value from 0 through 1 giving the target share of published tile-index coverage. This is geometric catalog coverage, not a data-quality measure.
cache_dir: A non-empty character path for the package cache. The session-temporary default avoids writing to the user's home directory. Set an explicit path to reuse catalogs, source files, and VRTs across sessions.
refresh: A character scalar controlling catalog access: "if_stale", "never", or "always". "never" requires an existing cached catalog and performs no catalog request.
quiet: A length-one logical suppressing routine informational messages.

Value

A terra::SpatVector with selected tile metadata. Coverage diagnostics are attached as the "coverage" attribute and the normalized native-resolution policy as "resolution_spec". Important fields include tile ID, native resolution, UTM zone, delivery date, intersection area and fraction, source URLs, expected SHA-256 checksums, selection rank/reason, and whether the tile was added as a coverage fallback.

AOI inputs

aoi must resolve to polygon or multipolygon geometry with a known coordinate reference system (CRS). Accepted inputs are:

a terra::SpatVector;
an sf::sf data frame or sf::sfc geometry vector;
a terra::SpatRaster, whose extent and CRS define the AOI;
a terra::SpatExtent, interpreted as longitude/latitude in EPSG:4326;
a numeric c(xmin, ymin, xmax, ymax) bounding box in EPSG:4326;
a local vector-file path readable by terra::vect(); or
a WKT or GeoJSON character string, interpreted as EPSG:4326.

Remote AOI URLs are refused. Numeric bounding boxes must be ordered and fall within valid longitude/latitude bounds. Point and line geometries are not accepted as areas of interest.

Examples

aoi <- c(xmin = -74.045, ymin = 40.675, xmax = -73.995, ymax = 40.715)

# \donttest{
tiles <- bluertopo_tiles(aoi)
# }