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Two strategies: "centers" assigns every non-NA raster cell centre to an H3 cell at res and averages (right when hexagons are larger than raster cells); "centroids" samples the raster at each requested hexagon's centroid (right when hexagons are smaller). "auto" picks centres when the mean hexagon area is at least ratio times the raster cell area.

Usage

h3_raster_to_cells(
  r,
  res,
  cells = NULL,
  method = c("auto", "centers", "centroids"),
  ratio = 3
)

Arguments

r

a terra::SpatRaster (single layer, lon/lat).

res

H3 resolution.

cells

optional hex strings to restrict/sample to (required for "centroids").

method

"auto", "centers" or "centroids".

ratio

hexagon-to-raster-cell area ratio above which "auto" uses centres (default 3).

Value

data frame with cell, value (mean), n_px (raster cells averaged; 1 for centroid sampling).