s2js

s2js is a Javascript port of the s2 spherical geometry library.

| github | npm | documentation | demo |

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``bash
npm install s2js
`

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The library is available as both ESM & CJS modules:

ESM

`js
import { s2 } from 's2js'
`

CJS

`js
const { s2 } = require('s2js')
`

CDN

`html

`

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s2js is a full-featured JavaScript/TypeScript port of Google's S2 Geometry library. It supports:

| Feature | Supported? | Notes |
| ----------------------------------- | :--------: | :----------------------------------------- |
| CellId, Cell | ✅ | Encoding, decoding, neighbors |
| Point, LatLng | ✅ | Spherical & Planar projections |
| Loop, Polygon | ✅ | Polygons, potentially with holes |
| Polyline | ✅ | Represents linear paths |
| RegionCoverer | ✅ | Cover regions (loops, polys) with S2 cells |
| GeoJSON <> S2 conversions | ✅ | Supports all GeoJSON geometry types |
| Polygon contains/intersects | ✅ | Point-in-polygon & shape intersection |
| Union, Intersection, Difference | ✅ | Basic boolean polygon operations |
| BigInt cell/token conversion | ✅ | Handles full 64-bit cell IDs |
| CellIndex, ClosestCellQuery | ✅ | Query a list of cells with various shapes |


TODO: ADD CLOSESTEDGEQUERY HERE

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The library is essentially feature compatible with the Golang library: https://github.com/golang/geo

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The library is written in Typescript and exports type definitions.

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The supplementary geojson module provides convenience functions for working with GeoJSON data in S2:

`js
import { geojson } from 's2js'

const s2Polyline = geojson.fromGeoJSON({
type: 'LineString',
coordinates: [
[102.0, 0.0],
[103.0, 1.0],
[104.0, 0.0],
[105.0, 1.0]
]
})
`

The RegionCoverer supports all geometry types including multi-geometries:

`js
const coverer = new geojson.RegionCoverer({ maxCells: 30 })

const union = coverer.covering({
type: 'Polygon',
coordinates: [
[
[100.0, 0.0],
[101.0, 0.0],
[101.0, 1.0],
[100.0, 1.0],
[100.0, 0.0]
]
]
})
``

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If you'd like to contribute a module please open an Issue to discuss.

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© 2024 Peter Johnson <github:missinglink>

This source code is published under the Apache-2.0 license.