What's New

v1.0

v1 is the first stable release of A5. If you are upgrading from 0.x, see the Upgrade Guide.

Cell IDs

• New teohedral space-filling curve which does not self-intersect, greatly improving performance
• As a consequence, while cell geometry is unchanged, cell IDs change. Cell IDs are now frozen and will not change in future versions
• Resolution 1 cells are now also pentagons, so the system has a single cell topology throughout

Coverings

• Coverings: compacted sets of cells that record their resolution with a compaction marker, providing an efficient way to represent regions of cells
• Coverings have a suite of new operators which work with the compacted data directly, unlocking previously impossible workflows:
  • Set operations: union, intersect and difference
  • Predicates: contains and overlaps
  • Measures: count and area

See Coverings example for demo

Spatial hierarchy functions

• cellToSubcells returns the finer resolution cells that cover (by centroid) a given cell
• cellToSupercell is the inverse relation

See Hierarchy example for demo

Performance

Large performance gains across all APIs, in part thanks to the new teohedral curve, in part due to many targeted optimizations. Selected benchmarks are shown below; note in particular the performance of polygonToCells for high resolutions.

API	Benchmark	v0.10	v1.0	Speedup
polygonToCells	Brazil res 6	2.66 ms	1.55 ms	1.72×
polygonToCells	Brazil res 8	14.29 ms	4.86 ms	2.94×
polygonToCells	Brazil res 10	131.26 ms	15.00 ms	8.75×
polygonToCells	Brazil res 12	1.96 s	49.84 ms	39.40×
lineStringToCells	London–Paris res 9	590.70 µs	47.00 µs	12.57×
lineStringToCells	round-the-world res 6	5.11 ms	472.90 µs	10.81×
compact	UK res 10	320.32 µs	29.37 µs	10.91×
gridDisk	k=1	1.55 µs	1.16 µs	1.34×
gridDisk	k=5	71.22 µs	19.83 µs	3.59×
gridDisk	k=20	1.64 ms	397.75 µs	4.12×
gridDiskVertex	k=5	143.27 µs	35.79 µs	4.00×
sphericalCap	res 12, 5 km	201.07 µs	54.09 µs	3.72×
lonLatToCell	res 5	1.87 µs	848.5 ns	2.20×
lonLatToCell	res 15	2.37 µs	966.1 ns	2.46×
lonLatToCell	res 30	5.50 µs	1.15 µs	4.77×
cellToLonLat	res 5	290.8 ns	228.2 ns	1.27×
cellToLonLat	res 15	348.5 ns	283.8 ns	1.23×
cellToLonLat	res 30	524.0 ns	337.1 ns	1.55×

Website

• New landing page
• All documentation reviewed and rewritten
• Code examples now render in 5 languages (DuckDB, Python, R, JavaScript & Rust)
• Visual examples refreshed