A GDAL-readable source: path + band + optional nodata sentinel.

Created by lazy_source(). A declared nodata on an integer source promotes the source's output dtype to f32 so NaN can carry nodata downstream; the executor rewrites value == nodata to NaN at read time.

Usage

SourceNode(
  id = integer(0),
  parents = integer(0),
  grid = GridSpec(),
  role = character(0),
  path = character(0),
  band = integer(0),
  nodata = integer(0),
  block_dim = integer(0),
  open_options = character(0),
  resampling = "near",
  scale = numeric(0),
  offset = numeric(0),
  name = character(0),
  collapsed = integer(0),
  decode = list()
)

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().

path

Path or VSI URL readable by GDAL.

band

1-based band index.

nodata

Length-0 (absent) or length-1 nodata sentinel value.

block_dim

Native GDAL block size (length 2), or length 0 if unknown; the chunking pass snaps chunk sizes to it.

open_options

GDAL open options ("KEY=VALUE"), e.g. GTI FILTER.

resampling

GDAL resampling used when a read reprojects/rescales the source onto the analysis grid (default "near").

scale, offset

Length-0 (absent) or length-1 band affine applied inside the read kernel after sentinel -> NaN (see lazy_source()).

name

Optional display name (the asset or band name). Pure metadata, shown by plan_view(); set by lazy_dataset().

collapsed

Node ids of the single-band sources a band-stack collapse folded into this multi-band read, in band order. Length 0 for an ordinary source.

decode

For a source whose 8-bit codes are decoded at read (see lazy_dataset()): the codes file (src), its first code (lo) and the table of decoded values (table); path is then the lookup-table VRT. Empty for an ordinary source.

Value

A SourceNode.