blistradius

Lightweight geospatial radius utilities for Node.js and the browser — great-circle distance, proximity checks, and circular bounding boxes.

Install

npm install blistradius

Usage

const {
  distance,
  isWithinRadius,
  boundingBox,
  filterWithinRadius,
} = require('blistradius');

const sf = { lat: 37.7749, lon: -122.4194 };
const la = { lat: 34.0522, lon: -118.2437 };

// Haversine distance in kilometers (default) or meters
distance(sf, la); // ~559
distance(sf, la, { unit: 'm' });

// Proximity check
isWithinRadius(sf, la, 600); // true

// Coarse geographic filter box for a 25 km radius
boundingBox(sf, 25);

// Keep only points inside the circle
filterWithinRadius(sf, [la, { lat: 37.78, lon: -122.41 }], 10);

API

| Function | Description | | --- | --- | | distance(a, b, options?) | Great-circle distance (unit: 'km' | 'm') | | isWithinRadius(center, target, radius, options?) | Whether target is inside the circle | | boundingBox(center, radiusKm) | Approximate lat/lon bounding box | | filterWithinRadius(center, points, radius, options?) | Filter an array of points | | toRadians(degrees) / toDegrees(radians) | Angle helpers |

License

MIT