LIFE.js

NAME

life-metric reads LIFE extinction-risk maps in browsers and Node.js.

SYNOPSIS

import { open } from "life-metric";

const life = await open();
const raster = await life.read("arable_0.25", {
  bounds: [43, -26, 51, -12],
  taxon: "AVES",
});
console.log(raster.data, raster.width, raster.height, raster.units);

DESCRIPTION

LIFE.js reads regions and samples points from LIFE Zarr v3 stores. It returns Float32Array or Float64Array values with plain metadata. Raster values are ordered by band, row, then column. One client reuses metadata and fetched data.

Scores measure the change in expected extinctions per square kilometre of land changed. Positive scores mean more extinctions, and negative scores mean fewer. Missing scores are NaN. Changed-area layers use square metres; zero scores and zero area are valid data.

INSTALLATION

npm install life-metric

Use Node.js 18 or newer, or a browser with an ESM bundler or import map.

USAGE

open() reads the published v1.01 store. Pass a URL to open another store. life.metadata describes its scenarios, curves, taxa, layers, and resolution levels. versions() lists the releases in the published catalogue.

Reads require bounds, a pixel window, or a GeoJSON polygon. Bounds use [west, south, east, north] in WGS84 degrees. Point samples use [longitude, latitude] pairs.

const scores = await life.sample("arable_0.25", [[47, -19.5]], { taxon: "AVES" });
console.log(JSON.stringify(Array.from(scores)));
const bytes = await life.download("arable_0.25", { bounds: [43, -26, 51, -12] });

Downloads return GeoTIFF bytes with CRS, units, citation, and data terms. They are uncompressed and limited to 16 million values. Use native resolution for calculations; coarser levels are intended for display. Requests accept an AbortSignal for cancellation.

The API guide explains masks, coordinate placement, version selection, and MapLibre. The numbered examples provide runnable scripts and browser pages. From a repository checkout, run npm ci and npm run example -- read to read a region.

TERMS OF USE

The code is MIT licensed. The data may not be used for commercial or revenue-generating purposes, nor redistributed in their original form, without written permission from IBAT (ibat@ibat-alliance.org). Read life.metadata.termsOfUse for the full terms.

SEE ALSO

The method is described by Eyres et al. (2025), LIFE: A metric for mapping the impact of land-cover change on global extinctions. The data of record and published stores are available separately. See LIFE.py for the Python client and quantifyearth/LIFE to regenerate LIFE from source data.