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Focal (stencil) op. radius is the halo in pixels; boundary is "nodata", the only policy: cells beyond the raster edge are NaN. Created by focal_map() and focal_kernel().

FocalNode.Rd

Focal (stencil) op. radius is the halo in pixels; boundary is "nodata", the only policy: cells beyond the raster edge are NaN. Created by focal_map() and focal_kernel().

Usage

FocalNode(
  id = integer(0),
  parents = integer(0),
  grid = GridSpec(),
  role = character(0),
  fn = function() NULL,
  radius = integer(0),
  boundary = character(0),
  weights = integer(0)
)

Arguments

id

Integer node id (assigned by graph_add()).

parents

Integer ids of parent nodes (may be empty).

grid

Output GridSpec of this node.

role

Optional semantic role tag (e.g. "mask", set by apply_mask()). Pure metadata: never read by the planner or executors; surfaced by plan_draw() and plan_view().

fn

Neighbourhood function (over the list of shifted arrays).

radius

Halo radius in pixels.

boundary

Boundary policy: "nodata".

weights

Optional linear kernel, flattened row-major over (dy, dx), length (2*radius+1)^2. When present the op is the weighted sum and is differentiable wrt the weights.

Value

A FocalNode.