Cells traced by a great-circle linestring

Returns the A5 cells at resolution whose pentagons are intersected by the great-circle polyline connecting the supplied waypoints. Output is uncompacted, in discovery order along the path, with duplicates removed first-seen. Multi-feature inputs (a MULTILINESTRING or an sfc of multiple linestrings) are handled natively: per-feature cell sequences are concatenated in feature order with first-seen deduplication.

Usage

a5_linestring_to_cells(x, resolution)

Arguments

x

A linestring-like geometry. One of:

• Any geometry handleable by wk::wk_handle() containing one or more LINESTRING / MULTILINESTRING features.

• A SpatVector of linestrings (requires the terra package).

• A two-column numeric matrix (cbind(lon, lat)) of waypoints.

• A data.frame with columns lon and lat.

resolution

Integer scalar target resolution (0–30).

Value

An a5_cell vector at resolution.

Details

Consecutive waypoints are connected by great-circle arcs (not rhumb lines or planar segments), so antimeridian-crossing paths work transparently when written in unwrapped lon/lat.

Matrix and data.frame inputs are treated as a single linestring; for multi-feature data, pass an sf, sfc, wk, or SpatVector geometry instead.

See also

a5_polygon_to_cells(), a5_grid_disk().

Examples

line <- wk::wkt("LINESTRING (2.35 48.86, -0.13 51.51)")
cells <- a5_linestring_to_cells(line, resolution = 6)
length(cells)
#> [1] 6