geoprimsField-grade geospatial math

H3 cell at local IJ (localIjToCell)

The cell at local IJ coordinates around an origin cell, undoing cellToLocalIj.

Go the other way: H3 local IJ for a cell (cellToLocalIj) →

892a847148fffff

That is 892a847148fffff.

Latitude
Longitude
Provenance
Computed by
indexing.h3.local-ij-to-cell 1.0.0, core 0.1.0
Model
H3 C localIjToCell (h3o 0.11): the IJ plane around the origin folded back onto the icosahedron
Accuracy
The same cells as H3 C 4.4.1, which are exact indexes, and a round trip through cellToLocalIj returns the cell it started from
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

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How we got thisFormula, worked example, sources, and proof

Model: H3 C localIjToCell (h3o 0.11): the IJ plane around the origin folded back onto the icosahedron

Accuracy: The same cells as H3 C 4.4.1, which are exact indexes, and a round trip through cellToLocalIj returns the cell it started from

When to use this: Use this to turn grid arithmetic back into cells: having moved by a vector in local IJ around an origin, this says which cell you landed on. It is the other half of working on the H3 grid as a plane. A regular pattern is laid out this way one cell at a time — a lattice of sample sites at a fixed spacing, a block of cells offset from a reference point, or the neighbour two steps along one axis — by naming the coordinates you want rather than by walking the grid to find them.

Limitations: The coordinates only mean something with the origin they were measured from, so the same pair around a different anchor gives a different cell. Coordinates far from the origin, or across one of the twelve pentagons, have no cell, and H3 refuses rather than answering wrongly. The cell comes back at the origin's resolution.

Worked example: Back to the cell east of downtown Pittsburgh. Source: H3 localIjToCell.

You enter

I
309
J
2470
Origin
892a8471487ffff

You get

Cell
892a847148fffff
Latitude
40.44453123°
Longitude
-79.986067854°

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.

Checked against: 22 golden test vectors (download the test vectors, each with its source and tolerance). See how results are checked and every source.

Sources

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