Find which rows of y are identical to each row of x within a tolerance

Returns the row numbers of y that have the same type and structure as each row of x, with every coordinate within tolerance of its counterpart. This is the sparse form of ga_equals_exact(), and matches sf::st_equals_exact().

Usage

ga_sparse_equals_exact(x, y, tolerance = 0)

Arguments

x

a GeoArrow geometry array

y

a GeoArrow geometry array

tolerance

the largest planar distance allowed between matching coordinates; length 1 or the same length as x

Value

a list array of 1 based row numbers into y, the same length as x

Details

ga_sparse_equals_exact() indexes y in a packed Hilbert R-tree and compares only the rows whose bounding boxes come within tolerance of the box of the row of x. It compares coordinates in order, so it does not match a line to its reverse; use ga_sparse_equals_topo() for that.

ga_sparse_equals_exact() returns a zero length element for a row of x that matches nothing. It returns a null element for a null or empty geometry in x, and for a tolerance that is NA or negative.

See also

Other topology: ga_contains(), ga_coordinate_position(), ga_dimension(), ga_equals_exact(), ga_filter(), ga_is_empty(), ga_join(), ga_relate(), ga_sparse_intersects(), ga_sparse_pairs()

Examples

nc <- as.data.frame(read_shapefile(
  system.file("shape/nc.shp", package = "sf")
))
shifted <- ga_translate(nc$geometry, 0.001, 0)

# each county matches its shifted copy once the tolerance covers the shift
as.vector(ga_sparse_equals_exact(nc$geometry, shifted, 0))[1:3]
#> <list_of<double>[3]>
#> [[1]]
#> numeric(0)
#> 
#> [[2]]
#> numeric(0)
#> 
#> [[3]]
#> numeric(0)
#> 
as.vector(ga_sparse_equals_exact(nc$geometry, shifted, 0.01))[1:3]
#> <list_of<double>[3]>
#> [[1]]
#> [1] 1
#> 
#> [[2]]
#> [1] 2
#> 
#> [[3]]
#> [1] 3
#>