Changes in version 0.1.0 (2026-09-08)                  

Initial release of spatcovar, an R package providing a consistent,
pipeable interface for constructing commonly used spatial covariates
directly on sf polygon data frames.

Core Functions

  - spat_area(): Calculates polygon geometric areas with conversion
    across metric and customary area units ("m2", "km2", "ha", "mi2").
    Uses geodesic measurement on geographic coordinate reference systems
    (via sf/s2) and planar measurement on projected systems.
  - spat_distance(): Computes shortest geometry-to-geometry ("minimum"),
    centroid-to-feature ("centroid"), or interior point-on-surface
    ("point_on_surface") distances from target polygons to reference
    features. Employs indexed nearest-feature search to avoid computing
    full pairwise distance matrices. Supports output in "m", "km", and
    "mi".
  - spat_count(): Counts source points, lines, or polygons intersecting
    each target polygon using explicit topological intersection
    semantics (including boundary-touching features). Multi-geometry
    features count as single source features.
  - spat_length(): Clips line features to polygon boundaries and
    measures total linework length per polygon. Explicitly handles
    native linear units of the projected coordinate reference system
    before converting to the requested unit ("m", "km", "mi").
  - spat_overlap(): Evaluates spatial overlap between target and source
    polygon layers, returning total overlap area (measure = "area"),
    coverage fraction relative to target area (measure = "share"), or
    intersecting polygon counts (measure = "count"). Issues an
    informative warning when source polygons have positive-area
    duplicate coverage among themselves.
  - spat_raster(): Computes coverage-fraction-weighted zonal summary
    statistics ("mean", "median", "min", "max", "sum", "count", "stdev")
    from single-layer raster grids using the exactextractr engine.
    Preserves valid zero values and returns NA across all requested
    statistics when a polygon has zero valid non-NA raster cell support.
  - spat_diagnostics(): Retrieves structured operation metadata attached
    when diagnostics = TRUE is passed to any core function.

Synthetic Example Datasets

  - Provides five lightweight, self-contained synthetic fixtures in
    EPSG:32632 for examples, testing, and reproducible workflows without
    external file dependencies: example_polygons(), example_points(),
    example_lines(), example_grid(), and example_raster().

Design Guarantees & Semantics

  - Row and Geometry Preservation: Output data frames retain the exact
    row count, row order, and original geometry of the input target
    polygons.
  - Safe Geometry Repair: Invalid geometries are repaired on internal
    copies used for computation (repair = TRUE by default); the geometry
    column returned to the user is never altered.
  - Coordinate Reference System Policy: Enforces strict validation
    requiring known coordinate reference systems on all vector and
    raster inputs. spat_length() strictly requires a projected (planar)
    CRS.
  - Dynamic Output Column Naming: Derives deterministic, unit-aware
    column names by default (e.g. area_km2, dist_m, length_km,
    overlap_share), with user override via the name argument.
  - Collision Protection: Prevents accidental overwriting of existing
    data frame columns unless explicitly allowed with overwrite = TRUE.