Changes in version 0.1.3                        

Iteration extending controlledburn from polygon-only to a unified
geometry rasterizer over polygon, line, and point input. Output schema
gains type-pure tables; the unification follows the geometric structure
of measure-on-a-grid as one operation parameterised by Hausdorff
dimension. Design philosophy and decisions are recorded in
inst/docs-design/unified-geometry-rasterization.md.

Breaking changes

  - Polygon boundary cells: $edges$weight renamed to $edges$fraction to
    reflect what the column carries (a dimensionless fraction in
    [0, 1]). [materialise_chunk()] reads either name for forward
    compatibility with cached results, but new code should use
    $edges$fraction.

  - burn_sparse() now errors on line and point input. Previously it fell
    through to a path that produced silent-empty (points) or
    silently-mistyped (lines) output. The error message redirects to
    burn_scanline().

What's new

  - burn_scanline() accepts LINESTRING, MULTILINESTRING, POINT, and
    MULTIPOINT alongside the existing POLYGON / MULTIPOLYGON support.
    Output schema gains $lines (row, col, length, id; absolute length in
    CRS units) and $points (row, col, id; no measure column — implicit
    weight = 1).

  - materialise_chunk() handles all four tables. Line cells contribute
    length, point cells contribute count, polygon cells contribute
    fraction. Mixed-kind input errors rather than silently combining
    units; filter to one kind via id = first.

  - print.controlledburn reports $lines and $points counts when present.

  - GeometryCollection input is rejected with a warning. Mixed-dimension
    input would produce a sparse table where rows from different kinds
    carry different units — caller must split into homogeneous groups
    and run separate burns. Curved types (CircularString, CompoundCurve,
    etc.) must be linearised by the caller before passing in.

Internals

  - walk_polyline(): cell-stepping walker extracted from walk_ring().
    Geometry-agnostic; takes a closed parameter that selects whether to
    push back coords for the start-cell-reentry case (true for rings,
    false for open lines). The polygon path runs the existing
    winding-sweep post-processing on the walker's output; the line path
    sums per-cell segment lengths from the same CellMap.

  - process_line(): walks lines on the full grid (no shrink_to_fit),
    because horizontal/vertical lines have a degenerate bbox that
    Box::empty() reports as true. Walker cost is O(cells touched), so
    the bbox-shrinking optimisation is dead weight for lines anyway.

  - process_point(): trivial. Computes cell index via Grid::get_row /
    get_column, drops out-of-extent silently.

  - Edge zoo (tests/testthat/test-edge-zoo.R) pins canonical rasterizer
    edge cases by category (Horizontal, Sub-pixel, Alignment, Precision,
    Topology, Collinear, CRS-boundary). Each test pins a convention, not
    just a numerical expectation, so the test surface doubles as API
    contract documentation.

                        Changes in version 0.1.0                        

Complete rewrite of controlledburn using the exactextract algorithm
(Daniel Baston, vendored from exactextractr) for exact polygon-grid
coverage fractions.

What's new

  - burn_scanline(): O(perimeter) scanline sweep with winding-number
    interior classification and exact boundary coverage fractions. No
    dense matrix allocation — output is sparse runs + edges tables.

  - burn_sparse(): Reference implementation using the exactextract dense
    algorithm, compressed to the same sparse output format.

  - materialise_chunk(): Opt-in expansion to dense matrix or vector,
    with per-polygon-id filtering.

  - Default grid parameters: extent derived from geometry bbox via
    wk::wk_bbox(), dimension auto-fitted to 256 cells on the long axis
    preserving aspect ratio, or specified as resolution.

  - Geometry input via wk::wkb(), geos_geometry, sfc, blob, or raw WKB
    list (compatible with vapour/gdalraster output).

  - Moved from Rcpp to cpp11, using libgeos for GEOS access.

Internals

  - Scanline algorithm: lightweight walk using Box::crossing() directly
    (no Cell class allocation), winding-count interior classification,
    analytical single-traversal coverage via perimeter_distance().

  - Validated against burn_sparse across 52 test cases: simple shapes,
    NC counties, shared boundaries, edge cases (grid-aligned edges,
    slivers, extent clipping, degenerate shapes).

  - O(perimeter) scaling confirmed by benchmark: 17× faster than dense
    at 3200×3200 resolution for complex shapes. Memory: sparse output
    ~50 MB vs ~2 GB dense for real-world 32K×16K grids.

History

  - Derived from fasterize (Noam Ross, EcoHealth Alliance) — original
    scanline edge logic for polygon rasterization.

  - Previous controlledburn (0.0.2) returned binary in/out run-length
    indexes without coverage fractions. That code is archived at
    archive0-2026-02-13 branch.

                        Changes in version 0.0.2                        

  - Basic function working, return a list of triplets of zero-index
    start,end,line index.

  - Raster package objects and use removed.

  - Converted from fasterize edge scanline logic, to not materialize any
    raster data. Armadillo usage removed.