a5R-package: a5R: A5 Pentagonal Geospatial Index for R

In a5R: 'A5' Discrete Global Grid System

a5R: A5 Pentagonal Geospatial Index for R

Description

R bindings for the A5 pentagonal geospatial index / discrete global grid system, powered by the a5 Rust crate via extendr.

Cell type

• a5_cell() — construct cell ID vectors

• is_a5_cell() / a5_is_valid() — type test and validation

• a5_u64_to_hex() / a5_hex_to_u64() — hex string conversion

Indexing

• a5_lonlat_to_cell() — coordinates to cell IDs

• a5_cell_to_lonlat() — cell IDs to centre coordinates

Geometry

• a5_cell_to_boundary() — cell boundary polygons (WKB or WKT)

• a5_cell_area() — cell area at a given resolution

• a5_cell_distance() — distance between cell centroids

• a5_get_num_cells() — total cell count at a resolution

• a5_get_num_children() — child count between resolutions

Hierarchy

• a5_get_resolution() — extract resolution from cell IDs

• a5_cell_to_parent() — navigate to coarser cells

• a5_cell_to_children() — navigate to finer cells

• a5_get_res0_cells() — the 12 root cells

• a5_compact() / a5_uncompact() — compress and expand cell sets

Traversal

• a5_grid_disk() — neighbours by hop count

• a5_spherical_cap() — neighbours by great-circle distance

Grid generation

• a5_grid() — fill a bbox or geometry with cells

Arrow & Parquet

• a5_cell_from_arrow() / a5_cell_to_arrow() — lossless conversion to/from Arrow uint64

Configuration

• a5_set_threads() / a5_get_threads() — multi-threading control

Vignettes

• vignette("a5R") — getting started

• vignette("multithreading") — parallel processing

• vignette("internal-cell-representation") — how cell IDs are stored

• vignette("arrow-parquet") — Arrow and Parquet interop

Author(s)

Maintainer: Hugh Graham [e-mail]

Other contributors:

• belian.earth [copyright holder]

See Also

Useful links:

• https://github.com/belian-earth/a5R

• https://belian-earth.github.io/a5R/

• Report bugs at https://github.com/belian-earth/a5R/issues

a5R documentation built on March 26, 2026, 5:10 p.m.