Build a QA-bitmask predicate.

Returns a predicate \(f) ... for mask()'s where argument that flags a pixel bad when any of the given bits is set. Nodata pixels are treated as clear (matching the QA-fill convention). Use for packed-flag QA bands (HLS Fmask, Landsat QA_PIXEL) where a value list cannot express the test; categorical bands (Sentinel-2 SCL) use a plain value vector instead.

Usage

qa_bits(bits)

Arguments

bits

Integer bit positions (0-based) that mark a pixel as bad.

Value

A predicate function of one array, returning a 0/1 mask: pass it as mask()'s where, or apply it directly with lazy_map().