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Map an output-chunk window on out_grid to the minimal input window required on in_grid.

cross_grid_window.Rd

Same CRS: exact affine math (north-up grids, so window corners are extremal). Different CRS: bounds are transformed with gdalraster::transform_bounds(), which densifies the boundary so curved edges (e.g. parallels in a transverse Mercator zone) cannot shrink the window; a safety margin of garry_opt("window_margin") input cells is then added.

Usage

cross_grid_window(
  out_grid,
  in_grid,
  x_off,
  y_off,
  x_size,
  y_size,
  margin = NULL
)

Arguments

out_grid, in_grid

GridSpecs of the consumer and producer.

x_off, y_off, x_size, y_size

0-based output window on out_grid.

margin

Safety margin in input cells; defaults to 0 for same-CRS windows and garry_opt("window_margin") across CRS.

Value

A list with the 0-based input window.

Details

Returns a list (x_off, y_off, x_size, y_size), 0-based, clipped to in_grid. A window fully outside in_grid returns zero sizes.