bearing.js

Structural geology stereonet library in pure JavaScript. No dependencies.

Live demo

Features

• Equal-area (Schmidt) and equal-angle (Wulff) projections
• Planes, poles, lines, great circles, small circles
• Kernel-density contouring (Kamb method)
• Eigenvalue decomposition, Woodcock and Vollmer fabric parameters, Bingham statistics
• Attitude I/O: dip-direction/dip, strike/dip, quadrant notation
• SVG rendering with no DOM dependencies
• ~24 KB minified, ~8 KB gzipped

Install

npm install

Usage

As an ES module:

import { Stereonet } from './src/index.js';

const sn = new Stereonet();
sn.plane(120, 45);
sn.pole(120, 45);

document.body.innerHTML = sn.svg();

As a bundled IIFE (browser global):

npm run build

<script src="bearing.js"></script>
<script>
  const sn = new bearing.Stereonet();
  sn.plane(120, 45);
  document.body.innerHTML = sn.svg();
</script>

API

| Module | Description | |--------|-------------| | Stereonet | Main class — add planes, poles, lines, contours, render to SVG | | conversions | Attitude conversions (dip-direction, strike, direction cosines) | | statistics | Eigenvalues, mean vector, Fisher, Woodcock, Vollmer, Bingham | | io | Parse attitude strings and text blocks | | equalArea / equalAngle | Projection functions | | vec3 / mat3 | 3D vector and matrix operations | | curves | Small circles, great circles as point sequences | | computeContours | Kernel-density contouring | | SvgBuilder | Low-level SVG path/element builder |

Tests

npm test

222 tests using Node.js built-in test runner.

License

MIT

GCU Classification

WA — Works in an Airplane. Fully offline, single HTML file, zero network calls. Deployable on air-gapped mine site laptops, field camp tablets, or opened from a USB stick.