Mixed grids and output grid

In CRAN or offline builds, network-dependent chunks are not evaluated.

New York Harbor is the primary public AOI for the examples, but its current small plan is a compatible 4 m grid. This example uses BlueTopo tiles covering Key West and Boca Chica Channel because the documented secondary AOI currently intersects 4 m and 8 m source grids and therefore demonstrates mixed native-grid behavior.

Mixed native grids are preserved unless the user asks for a single output grid. combine = "single" needs an explicit output grid when native grids are incompatible. Resampled uncertainty values are not original source cells, and contributor resampling must be nearest-neighbor.

Example area

Native mixed-grid extraction

native <- bluertopo(
  real_aoi,
  resolution = "native",
  coverage = "fill",
  combine = "auto",
  details = TRUE,
  progress = FALSE,
  quiet = TRUE
)

if (!inherits(native$data, "SpatRasterCollection")) {
  stop("The documented real AOI no longer produces mixed native grids.", call. = FALSE)
}

Native grid footprints

Explicit single output grid

single <- suppressWarnings(bluertopo(
  real_aoi,
  layers = "elevation",
  resolution = "native",
  coverage = "fill",
  output_crs = "EPSG:26917",
  output_resolution = 100,
  combine = "single",
  details = TRUE,
  progress = FALSE,
  quiet = TRUE
))

The explicit grid is useful for workflows that require one raster, but it is a resampling operation. Native source-resolution selection remains separate from output-grid creation.