Test coverings

a5_contains() tests whether each cell is in a covering, and a5_overlaps() whether two coverings share any cell. Both work on the compacted cells, without expanding them, and element by element, recycling a length-one argument.

Usage

a5_contains(x, cell)

a5_overlaps(x, y)

Arguments

x

An a5_covering vector, or an object as_a5_covering() accepts.

cell

An a5_cell vector, each at the resolution of its covering.

y

An a5_covering vector, at the same resolution as x.

Value

A logical vector of the common size of the inputs. NA where either input is NA.

Details

a5_contains() is a point-in-polygon test once the point is indexed at the covering's resolution: a5_contains(covering, a5_lonlat_to_cell(lon, lat, a5_covering_resolution(covering))). The cell must be at the covering's resolution, or it is an error: A5 cells do not nest geometrically, so a finer cell is not guaranteed to lie inside the coarser cell that holds it in the index. An empty covering contains no cell.

See also

a5_set_operations.

Examples

poly <- wk::wkt("POLYGON ((-3.4 55.85, -3 55.85, -3 56.05, -3.4 56.05, -3.4 55.85))")
edinburgh <- a5_polygon_to_cells(poly, resolution = 12)

# point in polygon, at the covering's resolution
points <- a5_lonlat_to_cell(c(-3.19, -4.25), c(55.95, 55.86), resolution = 12)
a5_contains(edinburgh, points)
#> [1]  TRUE FALSE

cap <- a5_spherical_cap(points, radius = 5000)
a5_overlaps(edinburgh, cap)
#> [1]  TRUE FALSE