EA-Quad grid

Equal-Area Quadtree — square cells in a single global equal-area projection (EPSG:6933, EASE-Grid 2.0). Cell edges are powers of two kilometres (~1 m up to 1024 km) with exact hierarchical containment, so every cell of a given size covers the same ground area worldwide. Ids are S2-style hex tokens: a 64-bit Hilbert-curve index whose prefix is shared with every ancestor cell.

The interactive explorer below is rendered with deck.gl and behaves like the h3geo.org map: the EA-Quad precision follows the zoom level and cells are generated in the browser for whatever is in view. Two neighbouring precisions are shown at once — the current level with a darker, heavier border and the next finer level with a lighter, thinner one — so the aperture-4 nesting stays visible. Cell geometry is produced by the shared m3s_core WASM build (EPSG:6933 projection, power-of-two km grid, Hilbert-curve hex-token ids), so the browser and the Python package produce identical cells. GIS-native (lon, lat) order is used throughout.

Why EA-Quad?

Pick EA-Quad when cells must compare fairly across the globe: an 8 km cell covers the same ground area in Norway as in Kenya, so counts and densities aggregate without latitude bias. Sizes are plain powers of two (~1 m up to 1024 km), not abstract levels, which makes resolutions easy to reason about. The tradeoff: the squares are square in the EASE-Grid projection, so they look slightly stretched on a Web-Mercator basemap, and the ids mean nothing to tile servers. If you are feeding a web-map stack and equal area does not matter, use Quadkey grid or Slippy map tiles instead; if you want equal area with hexagonal adjacency, see H3 grid (approximate) or A5 grid (exact).

Usage

Encode a point and tile a small bounding box around Paris — same result in Python and JavaScript (both call the shared core):

Python

import m3s

cell = m3s.EAQuad.from_geometry((2.35, 48.86))            # (lon, lat)
cells = m3s.EAQuad.from_geometry((2.2, 48.8, 2.4, 48.9))  # bbox
print(cell.id, len(cells))

JavaScript

import * as m3s from "m3s";
await m3s.ready();

const cell = m3s.EAQuad.fromPoint(2.35, 48.86);            // (lon, lat)
const cells = m3s.EAQuad.fromBbox([2.2, 48.8, 2.4, 48.9]); // bbox
console.log(cell.id, cells.length);

from _deckmap import DeckExplorer, read_grid_js


DeckExplorer(
    center=(2.35, 48.86),
    zoom=12,
    grid_js=read_grid_js("eaquad"),
    hover="#ffeb3b",
    wasm=True,
)