H3 grid ring
The cells exactly k steps from a cell (gridRing), the hollow ring.
The ring at k = 2 has 12 cells.
| Cell |
|---|
| 892a847322fffff |
| 892a8471493ffff |
| 892a847149bffff |
| 892a847148bffff |
| 892a8471413ffff |
| 892a8471417ffff |
| 892a84714abffff |
| 892a84714a3ffff |
| 892a84714b7ffff |
| 892a847334fffff |
| 892a8473343ffff |
| 892a847335bffff |
Provenance
- Computed by
- indexing.h3.grid-ring 1.0.0, core 0.1.0
- Model
- H3 v4 gridRing (h3o 0.11)
- Accuracy
- Identical to H3 C
- Notes
- None
- Cites
- Uber Technologies and the H3 contributors, H3: A Hexagonal Hierarchical Geospatial Indexing System (API reference v4); Hydronium Labs, h3o: a Rust implementation of H3
Something look off?
How we got thisFormula, worked example, sources, and proof
Model: H3 v4 gridRing (h3o 0.11)
Accuracy: Identical to H3 C
When to use this: Use this when you want a hollow ring rather than a filled disk: the cells exactly k steps out. It is how a band at a given distance is selected, how a disk is built up one ring at a time, and how a search expands outward without repeating the cells it has already seen. Rings are how an expanding search is done without rework: take ring one, then ring two, stopping as soon as enough is found, instead of taking a large disk and discarding most of it.
Limitations: Like the disk, a ring is measured in grid steps rather than meters, and it is distorted near the twelve pentagons, where a ring can be incomplete. Rings at the same k have different ground radii at different resolutions. Near a pentagon a ring can come back incomplete or fail, so a search that relies on rings alone should handle that rather than assume six times k cells.
Worked example: Ring 2 around 892a8471487ffff. Source: H3 gridRing: 6k cells away from pentagons.
You enter
- Center cell
- 892a8471487ffff
- k (rings)
- 2
You get
- Cells
- 12
Review: Not yet independently reviewed by a GIS professional.
Last verified: 2026-09-18, when a maintainer last confirmed this tool's sources at the issuer. See the sources ledger.
Status: version 1.0.0, core 0.1.0. See this tool in the verification report.
Changes
- 2026-09-19, changed: Eight more H3 tools are stable: the cell inspector, grid ring, grid path, parent, children, compact, uncompact, and edges. On 300 cells at every resolution, one in eight a pentagon, they match H3 C exactly, including every path H3 C refuses; cell areas agree to 2e-8 relative even at resolution 15. Results are unchanged. Changelog
Checked against: 20 golden test vectors (download the test vectors, each with its source and tolerance). See how results are checked and every source.
Sources
- H3: A Hexagonal Hierarchical Geospatial Indexing System (API reference v4), Uber Technologies and the H3 contributors, H3 4.x documentation. Indexing, inspection, traversal, hierarchy, directed edges, vertexes, and resolution tables. Read free.
- h3o: a Rust implementation of H3, Hydronium Labs, 0.11.0 (tested against H3 C). CellIndex, LatLng, Resolution. Read free.
Terms
- H3: H3 hexagonal hierarchical index
- A global grid of hexagons (and 12 pentagons) at 16 resolutions, each cell about one-seventh the area of its parent, named by a 15-character index. Source: H3 hexagonal index
H3 — H3 hexagonal hierarchical index
A global grid of hexagons (and 12 pentagons) at 16 resolutions, each cell about one-seventh the area of its parent, named by a 15-character index.
Source: H3 hexagonal index